diff --git a/api/controllers/inner_api/__init__.py b/api/controllers/inner_api/__init__.py
index f47861cf274..277e0f5ec0e 100644
--- a/api/controllers/inner_api/__init__.py
+++ b/api/controllers/inner_api/__init__.py
@@ -17,6 +17,7 @@ inner_api_ns = Namespace("inner_api", description="Internal API operations", pat
 
 from . import mail as _mail
 from . import runtime_credentials as _runtime_credentials
+from .agent import files as _agent_files
 from .agent import tools as _agent_tools
 from .app import dsl as _app_dsl
 from .knowledge import retrieval as _knowledge_retrieval
@@ -30,6 +31,7 @@ api.add_namespace(inner_api_ns)
 __all__ = [
     "_agent_config",
     "_agent_drive",
+    "_agent_files",
     "_agent_tools",
     "_app_dsl",
     "_knowledge_retrieval",
diff --git a/api/controllers/inner_api/agent/files.py b/api/controllers/inner_api/agent/files.py
new file mode 100644
index 00000000000..7a5cad76440
--- /dev/null
+++ b/api/controllers/inner_api/agent/files.py
@@ -0,0 +1,198 @@
+"""Agent-owned inner endpoints for CLI file URL allocation."""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from flask_restx import Resource
+from pydantic import BaseModel, ConfigDict, ValidationError
+from sqlalchemy.orm import Session
+
+from configs import dify_config
+from controllers.common.schema import register_response_schema_models, register_schema_models
+from controllers.common.session import with_session
+from controllers.console.wraps import setup_required
+from controllers.inner_api import inner_api_ns
+from controllers.inner_api.plugin.wraps import get_user
+from controllers.inner_api.wraps import plugin_inner_api_only
+from core.plugin.entities.request import RequestDownloadFileMapping, RequestRequestUploadFile
+from core.tools.signature import bind_file_uri, get_signed_file_uri_for_plugin
+from fields.base import ResponseModel
+from libs.exception import BaseHTTPException
+from services.account_service import TenantService
+from services.file_request_service import FileRequestService
+
+
+class AgentFileRequestHttpError(BaseHTTPException):
+    error_code = "agent_file_request_failed"
+    description = "Agent file request failed."
+    code = 500
+
+    def __init__(self, *, error_code: str, description: str, status_code: int) -> None:
+        self.error_code = error_code
+        self.description = description
+        self.code = status_code
+        super().__init__(description)
+
+
+class AgentFileUploadRequestPayload(RequestRequestUploadFile):
+    tenant_id: str
+    user_id: str
+
+    model_config = ConfigDict(extra="forbid")
+
+
+class AgentFileDownloadRequestPayload(BaseModel):
+    tenant_id: str
+    user_id: str
+    user_from: Literal["account", "end-user"]
+    invoke_from: Literal[
+        "service-api",
+        "openapi",
+        "web-app",
+        "trigger",
+        "explore",
+        "debugger",
+        "published",
+        "validation",
+    ]
+    file: RequestDownloadFileMapping
+    for_frontend: bool = True
+
+    model_config = ConfigDict(extra="forbid")
+
+
+class AgentFileUploadRequestResponse(ResponseModel):
+    upload_uri: str
+
+
+class AgentFileDownloadRequestResponse(ResponseModel):
+    filename: str
+    mime_type: str | None = None
+    size: int
+    download_uri: str
+
+
+register_schema_models(inner_api_ns, AgentFileUploadRequestPayload, AgentFileDownloadRequestPayload)
+register_response_schema_models(
+    inner_api_ns,
+    AgentFileUploadRequestResponse,
+    AgentFileDownloadRequestResponse,
+)
+
+
+@inner_api_ns.route("/agent/files/upload-request")
+class AgentFileUploadRequestApi(Resource):
+    """Allocate an origin-free signed upload URI for the Agent CLI."""
+
+    @setup_required
+    @plugin_inner_api_only
+    @inner_api_ns.doc("inner_agent_file_upload_request")
+    @inner_api_ns.expect(inner_api_ns.models[AgentFileUploadRequestPayload.__name__])
+    @inner_api_ns.response(
+        200,
+        "Upload URI allocated",
+        inner_api_ns.models[AgentFileUploadRequestResponse.__name__],
+    )
+    @with_session(write=False)
+    def post(self, session: Session) -> dict[str, object]:
+        try:
+            payload = AgentFileUploadRequestPayload.model_validate(inner_api_ns.payload or {})
+        except ValidationError as exc:
+            raise AgentFileRequestHttpError(
+                error_code="invalid_request",
+                description=str(exc),
+                status_code=400,
+            ) from exc
+
+        tenant = TenantService.get_tenant_by_id(payload.tenant_id, session=session)
+        if tenant is None:
+            raise AgentFileRequestHttpError(
+                error_code="tenant_not_found",
+                description="tenant not found",
+                status_code=404,
+            )
+        try:
+            user = get_user(tenant.id, payload.user_id)
+            upload_uri = get_signed_file_uri_for_plugin(
+                filename=payload.filename,
+                mimetype=payload.mimetype,
+                tenant_id=tenant.id,
+                user_id=user.id,
+                conversation_id=payload.conversation_id,
+            )
+        except ValueError as exc:
+            raise AgentFileRequestHttpError(
+                error_code="user_not_found",
+                description=str(exc),
+                status_code=404,
+            ) from exc
+
+        return AgentFileUploadRequestResponse(upload_uri=upload_uri).model_dump(mode="json")
+
+
+@inner_api_ns.route("/agent/files/download-request")
+class AgentFileDownloadRequestApi(Resource):
+    """Allocate a transfer URI or frontend URL for one Agent CLI file."""
+
+    @setup_required
+    @plugin_inner_api_only
+    @inner_api_ns.doc("inner_agent_file_download_request")
+    @inner_api_ns.expect(inner_api_ns.models[AgentFileDownloadRequestPayload.__name__])
+    @inner_api_ns.response(
+        200,
+        "Download URI allocated",
+        inner_api_ns.models[AgentFileDownloadRequestResponse.__name__],
+    )
+    @with_session(write=False)
+    def post(self, session: Session) -> dict[str, object]:
+        try:
+            payload = AgentFileDownloadRequestPayload.model_validate(inner_api_ns.payload or {})
+        except ValidationError as exc:
+            raise AgentFileRequestHttpError(
+                error_code="invalid_request",
+                description=str(exc),
+                status_code=400,
+            ) from exc
+
+        if TenantService.get_tenant_by_id(payload.tenant_id, session=session) is None:
+            raise AgentFileRequestHttpError(
+                error_code="tenant_not_found",
+                description="tenant not found",
+                status_code=404,
+            )
+        try:
+            result = FileRequestService().request_download(
+                tenant_id=payload.tenant_id,
+                user_id=payload.user_id,
+                user_from=payload.user_from,
+                invoke_from=payload.invoke_from,
+                file_mapping=payload.file.model_dump(mode="python", exclude_none=True),
+            )
+        except ValueError as exc:
+            raise AgentFileRequestHttpError(
+                error_code="file_not_accessible",
+                description=str(exc),
+                status_code=404,
+            ) from exc
+
+        download_uri = result.download_uri
+        if payload.for_frontend:
+            download_uri = bind_file_uri(download_uri, dify_config.FILES_URL)
+
+        return AgentFileDownloadRequestResponse(
+            filename=result.filename,
+            mime_type=result.mime_type,
+            size=result.size,
+            download_uri=download_uri,
+        ).model_dump(mode="json")
+
+
+__all__ = [
+    "AgentFileDownloadRequestApi",
+    "AgentFileDownloadRequestPayload",
+    "AgentFileDownloadRequestResponse",
+    "AgentFileUploadRequestApi",
+    "AgentFileUploadRequestPayload",
+    "AgentFileUploadRequestResponse",
+]
diff --git a/api/controllers/inner_api/plugin/plugin.py b/api/controllers/inner_api/plugin/plugin.py
index 1171761fc53..221887f73c7 100644
--- a/api/controllers/inner_api/plugin/plugin.py
+++ b/api/controllers/inner_api/plugin/plugin.py
@@ -1,6 +1,7 @@
 from flask_restx import Resource
 from sqlalchemy.orm import Session
 
+from configs import dify_config
 from controllers.console.app.wraps import with_session
 from controllers.console.wraps import setup_required
 from controllers.inner_api import inner_api_ns
@@ -31,7 +32,7 @@ from core.plugin.entities.request import (
     RequestRequestUploadFile,
 )
 from core.tools.entities.tool_entities import ToolProviderType
-from core.tools.signature import get_signed_file_url_for_plugin
+from core.tools.signature import bind_file_uri, get_signed_file_uri_for_plugin
 from extensions.ext_database import db
 from graphon.model_runtime.utils.encoders import jsonable_encoder
 from libs.helper import length_prefixed_response
@@ -429,13 +430,14 @@ class PluginUploadFileRequestApi(Resource):
     )
     def post(self, user_model: Account | EndUser, tenant_model: Tenant, payload: RequestRequestUploadFile):
         # generate signed url
-        url = get_signed_file_url_for_plugin(
+        uri = get_signed_file_uri_for_plugin(
             filename=payload.filename,
             mimetype=payload.mimetype,
             tenant_id=tenant_model.id,
             user_id=user_model.id,
             conversation_id=payload.conversation_id,
         )
+        url = bind_file_uri(uri, dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
         return BaseBackwardsInvocationResponse(data={"url": url}).model_dump()
 
 
@@ -454,36 +456,33 @@ class PluginDownloadFileRequestApi(Resource):
         }
     )
     def post(self, payload: RequestRequestDownloadFile):
-        """Resolve signed download metadata for trusted external runtimes.
+        """Adapt a shared file request result to the Plugin backward contract.
 
-        Unlike end-user-facing upload/download APIs, this inner endpoint serves
-        trusted callers such as the ``dify-agent`` back proxy. The caller sends
-        flattened ``tenant_id`` / ``user_id`` / ``user_from`` / ``invoke_from``
-        context explicitly in the body, and ``FileRequestService`` rebuilds the
-        corresponding ``FileAccessScope`` before resolving the signed URL.
-
-        The response is control-plane metadata only: filename, mime type, size,
-        and the signed download URL. File bytes still flow through the existing
-        signed file endpoints rather than through this inner API.
+        ``FileRequestService`` rebuilds the caller's ``FileAccessScope`` and
+        resolves one origin-free signed URI. This controller binds that URI to
+        the Plugin-selected external or internal files base URL, then returns
+        the existing backward-invocation envelope.
         """
         tenant_model = db.session.get(Tenant, payload.tenant_id)
         if tenant_model is None:
             raise ValueError("tenant not found")
 
-        result = FileRequestService().request_download_url(
+        result = FileRequestService().request_download(
             tenant_id=tenant_model.id,
             user_id=payload.user_id,
             user_from=payload.user_from,
             invoke_from=payload.invoke_from,
             file_mapping=payload.file.model_dump(mode="python", exclude_none=True),
-            for_external=payload.for_external,
+        )
+        base_url = (
+            dify_config.FILES_URL if payload.for_external else (dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
         )
         return BaseBackwardsInvocationResponse(
             data={
                 "filename": result.filename,
                 "mime_type": result.mime_type,
                 "size": result.size,
-                "download_url": result.download_url,
+                "download_url": bind_file_uri(result.download_uri, base_url),
             }
         ).model_dump()
 
diff --git a/api/core/app/workflow/file_runtime.py b/api/core/app/workflow/file_runtime.py
index dec92c03b61..7bdabd93717 100644
--- a/api/core/app/workflow/file_runtime.py
+++ b/api/core/app/workflow/file_runtime.py
@@ -13,7 +13,7 @@ from configs import dify_config
 from core.app.file_access import DatabaseFileAccessController, FileAccessControllerProtocol
 from core.db.session_factory import session_factory
 from core.file import remote_fetcher
-from core.tools.signature import sign_tool_file
+from core.tools.signature import bind_file_uri, sign_tool_file_uri
 from core.workflow.file_reference import parse_file_reference
 from extensions.ext_storage import storage
 from graphon.file import FileTransferMethod
@@ -62,32 +62,42 @@ class DifyWorkflowFileRuntime(WorkflowFileRuntimeProtocol):
 
     @override
     def resolve_file_url(self, *, file: File, for_external: bool = True) -> str | None:
+        uri = self.resolve_file_uri(file=file)
+        if uri is None or file.transfer_method == FileTransferMethod.REMOTE_URL:
+            return uri
+        return bind_file_uri(uri, self._base_url(for_external=for_external))
+
+    def resolve_file_uri(self, *, file: File) -> str | None:
+        """Resolve a signed file URI without binding Dify-owned files to an origin.
+
+        Remote URLs retain their external absolute URL. Dify-owned files return
+        a signed ``/files/...`` URI that callers can bind to their own network
+        audience without exposing ``FILES_URL`` or ``INTERNAL_FILES_URL``.
+        """
+
         if file.transfer_method == FileTransferMethod.REMOTE_URL:
             return file.remote_url
         parsed_reference = parse_file_reference(file.reference)
         if parsed_reference is None:
             raise ValueError("Missing file reference")
         if file.transfer_method == FileTransferMethod.LOCAL_FILE:
-            return self.resolve_upload_file_url(
+            return self.resolve_upload_file_uri(
                 upload_file_id=parsed_reference.record_id,
-                for_external=for_external,
             )
         if file.transfer_method == FileTransferMethod.DATASOURCE_FILE:
             if file.extension is None:
                 raise ValueError("Missing file extension")
             self._assert_upload_file_access(upload_file_id=parsed_reference.record_id)
-            return sign_tool_file(
+            return sign_tool_file_uri(
                 tool_file_id=parsed_reference.record_id,
                 extension=file.extension,
-                for_external=for_external,
             )
         if file.transfer_method == FileTransferMethod.TOOL_FILE:
             if file.extension is None:
                 raise ValueError("Missing file extension")
-            return self.resolve_tool_file_url(
+            return self.resolve_tool_file_uri(
                 tool_file_id=parsed_reference.record_id,
                 extension=file.extension,
-                for_external=for_external,
             )
         return None
 
@@ -99,18 +109,34 @@ class DifyWorkflowFileRuntime(WorkflowFileRuntimeProtocol):
         as_attachment: bool = False,
         for_external: bool = True,
     ) -> str:
+        uri = self.resolve_upload_file_uri(upload_file_id=upload_file_id, as_attachment=as_attachment)
+        return bind_file_uri(uri, self._base_url(for_external=for_external))
+
+    def resolve_upload_file_uri(
+        self,
+        *,
+        upload_file_id: str,
+        as_attachment: bool = False,
+    ) -> str:
+        """Resolve a signed UploadFile URI without selecting an origin."""
+
         self._assert_upload_file_access(upload_file_id=upload_file_id)
-        base_url = self._base_url(for_external=for_external)
-        url = f"{base_url}/files/{upload_file_id}/file-preview"
+        uri = f"/files/{upload_file_id}/file-preview"
         query = self._sign_query(payload=f"file-preview|{upload_file_id}")
         if as_attachment:
             query["as_attachment"] = "true"
-        return f"{url}?{urllib.parse.urlencode(query)}"
+        return f"{uri}?{urllib.parse.urlencode(query)}"
 
     @override
     def resolve_tool_file_url(self, *, tool_file_id: str, extension: str, for_external: bool = True) -> str:
+        uri = self.resolve_tool_file_uri(tool_file_id=tool_file_id, extension=extension)
+        return bind_file_uri(uri, self._base_url(for_external=for_external))
+
+    def resolve_tool_file_uri(self, *, tool_file_id: str, extension: str) -> str:
+        """Resolve a signed ToolFile URI without selecting an origin."""
+
         self._assert_tool_file_access(tool_file_id=tool_file_id)
-        return sign_tool_file(tool_file_id=tool_file_id, extension=extension, for_external=for_external)
+        return sign_tool_file_uri(tool_file_id=tool_file_id, extension=extension)
 
     @override
     def verify_preview_signature(
diff --git a/api/core/tools/signature.py b/api/core/tools/signature.py
index 77d81bafbc1..02291bd2611 100644
--- a/api/core/tools/signature.py
+++ b/api/core/tools/signature.py
@@ -4,29 +4,52 @@ import hmac
 import os
 import time
 import urllib.parse
+from urllib.parse import urlsplit
 
 from configs import dify_config
 
 
+def bind_file_uri(uri: str, base_url: str) -> str:
+    """Bind a Dify-owned file URI to one caller-selected origin.
+
+    Explicit remote HTTP(S) URLs are already complete and pass through. Other
+    values must be origin-free ``/files/...`` URIs.
+    """
+
+    parsed = urlsplit(uri)
+    if parsed.scheme in {"http", "https"} and parsed.netloc:
+        return uri
+    if (
+        parsed.scheme
+        or parsed.netloc
+        or parsed.fragment
+        or uri.startswith("//")
+        or not parsed.path.startswith("/files/")
+    ):
+        raise ValueError("file URI must be an absolute HTTP(S) URL or a /files/ URI")
+    return f"{base_url}{uri}"
+
+
 def _secret_key() -> bytes:
     return dify_config.SECRET_KEY.encode()
 
 
-def sign_tool_file(tool_file_id: str, extension: str, for_external: bool = True) -> str:
-    """
-    sign file to get a temporary url for plugin access
-    """
-    # Use internal URL for plugin/tool file access in Docker environments, unless for_external is True
-    base_url = dify_config.FILES_URL if for_external else (dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
-    file_preview_url = f"{base_url}/files/tools/{tool_file_id}{extension}"
-
+def sign_tool_file_uri(tool_file_id: str, extension: str) -> str:
+    """Sign a ToolFile path without selecting a network origin."""
     timestamp = str(int(time.time()))
     nonce = os.urandom(16).hex()
     data_to_sign = f"file-preview|{tool_file_id}|{timestamp}|{nonce}"
     sign = hmac.new(_secret_key(), data_to_sign.encode(), hashlib.sha256).digest()
     encoded_sign = base64.urlsafe_b64encode(sign).decode()
 
-    return f"{file_preview_url}?timestamp={timestamp}&nonce={nonce}&sign={encoded_sign}"
+    return f"/files/tools/{tool_file_id}{extension}?timestamp={timestamp}&nonce={nonce}&sign={encoded_sign}"
+
+
+def sign_tool_file(tool_file_id: str, extension: str, for_external: bool = True) -> str:
+    """Sign a ToolFile URL for the browser or an internal Dify service."""
+
+    base_url = dify_config.FILES_URL if for_external else (dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
+    return bind_file_uri(sign_tool_file_uri(tool_file_id, extension), base_url)
 
 
 def sign_upload_file_preview_url(upload_file_id: str, extension: str) -> str:
@@ -64,13 +87,11 @@ def verify_tool_file_signature(file_id: str, timestamp: str, nonce: str, sign: s
     return current_time - int(timestamp) <= dify_config.FILES_ACCESS_TIMEOUT
 
 
-def get_signed_file_url_for_plugin(
+def get_signed_file_uri_for_plugin(
     filename: str, mimetype: str, tenant_id: str, user_id: str, conversation_id: str | None = None
 ) -> str:
-    """Build the signed upload URL used by the plugin-facing file upload endpoint."""
+    """Build a signed plugin-upload URI without selecting a network origin."""
 
-    base_url = dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL
-    upload_url = f"{base_url}/files/upload/for-plugin"
     timestamp = str(int(time.time()))
     nonce = os.urandom(16).hex()
     data_to_sign = f"upload|{filename}|{mimetype}|{tenant_id}|{user_id}|{conversation_id or ''}|{timestamp}|{nonce}"
@@ -86,7 +107,7 @@ def get_signed_file_url_for_plugin(
     if conversation_id:
         query_params["conversation_id"] = conversation_id
     query = urllib.parse.urlencode(query_params)
-    return f"{upload_url}?{query}"
+    return f"/files/upload/for-plugin?{query}"
 
 
 def verify_plugin_file_signature(
diff --git a/api/core/workflow/nodes/agent_v2/runtime_request_builder.py b/api/core/workflow/nodes/agent_v2/runtime_request_builder.py
index 09860998c89..126ce503f81 100644
--- a/api/core/workflow/nodes/agent_v2/runtime_request_builder.py
+++ b/api/core/workflow/nodes/agent_v2/runtime_request_builder.py
@@ -701,7 +701,7 @@ class WorkflowAgentRuntimeRequestBuilder:
                 "only the accepted file-mapping shape and the returned `reference`; never invent the `reference` "
                 "value.",
                 "If you are replying to the user in natural language and want them to open or download the produced "
-                "file, include the returned `download_url` in that reply instead of copying it into structured "
+                "file, include the returned `public_download_url` in that reply instead of copying it into structured "
                 "`final_output` unless the schema explicitly asks for it.",
                 *file_output_lines,
             ]
diff --git a/api/services/agent/prompt_mentions.py b/api/services/agent/prompt_mentions.py
index 5f42bffe3ff..a3690f4093a 100644
--- a/api/services/agent/prompt_mentions.py
+++ b/api/services/agent/prompt_mentions.py
@@ -320,7 +320,7 @@ def _format_output_mention(output: DeclaredOutputConfig) -> str:
             f"{output.name} (file output; create the file locally, run "
             f"`dify-agent file upload <path>`, then set final_output.{output.name} to a `tool_file` mapping "
             f"using the returned `reference`; if replying to the user in natural language, use the returned "
-            f"`download_url`; do not call final_output before upload succeeds, and do not use the local path, "
+            f"`public_download_url`; do not call final_output before upload succeeds, and do not use the local path, "
             "filename, URL, or a synthesized dify-file-ref as the reference)"
         )
     if (
@@ -332,7 +332,7 @@ def _format_output_mention(output: DeclaredOutputConfig) -> str:
             f"{output.name} (array[file] output; upload each produced file with "
             f"`dify-agent file upload <path>`, then set final_output.{output.name} to `tool_file` mappings "
             f"using the returned `reference` values; if replying to the user in natural language, use the returned "
-            f"`download_url`; do not call final_output before all uploads succeed, and do not use local paths, "
+            f"`public_download_url`; do not call final_output before all uploads succeed, and do not use local paths, "
             "filenames, URLs, or synthesized dify-file-ref values as references)"
         )
     return f"{output.name} ({output.type.value})"
diff --git a/api/services/agent_file_request_service.py b/api/services/agent_file_request_service.py
deleted file mode 100644
index 091fc9fc59b..00000000000
--- a/api/services/agent_file_request_service.py
+++ /dev/null
@@ -1,93 +0,0 @@
-"""Resolve a download request for a workflow file ref to a signed URL (Agent Files §3.1.1/§4.5).
-
-The dify-agent server calls this on behalf of a sandbox that needs to pull a
-``File`` / ``Array[File]`` workflow input. It binds the flattened file-access
-context as a ``FileAccessScope``, rebuilds the graphon ``File`` from the mapping
-(reusing tenant/user access checks), and returns an internal signed download URL
-plus metadata — never the file bytes. The dify-agent server / sandbox then GETs
-the URL directly from Dify API.
-"""
-
-from __future__ import annotations
-
-from collections.abc import Mapping
-from typing import Any
-
-from core.app.entities.app_invoke_entities import InvokeFrom, UserFrom
-from core.app.file_access.controller import DatabaseFileAccessController
-from core.app.file_access.scope import FileAccessScope, bind_file_access_scope
-from core.app.workflow.file_runtime import DifyWorkflowFileRuntime
-from factories import file_factory
-
-
-class FileDownloadRequestError(Exception):
-    """A download-request failure mapped to an HTTP status by the controller."""
-
-    code: str
-    message: str
-    status_code: int
-
-    def __init__(self, code: str, message: str, *, status_code: int = 400) -> None:
-        super().__init__(message)
-        self.code = code
-        self.message = message
-        self.status_code = status_code
-
-
-class AgentFileDownloadRequestService:
-    """Resolve a workflow file ref to a sandbox-accessible internal signed download URL."""
-
-    @classmethod
-    def resolve(
-        cls,
-        *,
-        tenant_id: str,
-        user_id: str,
-        user_from: str,
-        invoke_from: str,
-        file_mapping: Mapping[str, Any],
-    ) -> dict[str, Any]:
-        try:
-            scope_user_from = UserFrom(user_from)
-            scope_invoke_from = InvokeFrom(invoke_from)
-        except ValueError as exc:
-            raise FileDownloadRequestError("invalid_access_context", str(exc), status_code=400) from exc
-
-        if not isinstance(file_mapping, Mapping) or not file_mapping.get("transfer_method"):
-            raise FileDownloadRequestError("invalid_file_mapping", "file.transfer_method is required", status_code=400)
-
-        scope = FileAccessScope(
-            tenant_id=tenant_id,
-            user_id=user_id,
-            user_from=scope_user_from,
-            invoke_from=scope_invoke_from,
-        )
-        controller = DatabaseFileAccessController()
-        runtime = DifyWorkflowFileRuntime(file_access_controller=controller)
-        try:
-            with bind_file_access_scope(scope):
-                file = file_factory.build_from_mapping(
-                    mapping=file_mapping,
-                    tenant_id=tenant_id,
-                    access_controller=controller,
-                )
-                # Internal URL (for_external=False): the consumer is the agent backend /
-                # sandbox, not a browser. Resolves against INTERNAL_FILES_URL, falling
-                # back to FILES_URL when not configured.
-                download_url = runtime.resolve_file_url(file=file, for_external=False)
-        except ValueError as exc:
-            raise FileDownloadRequestError("file_not_accessible", str(exc), status_code=404) from exc
-
-        if not download_url:
-            raise FileDownloadRequestError(
-                "download_url_unavailable", "could not resolve a download URL for the file", status_code=502
-            )
-        return {
-            "filename": file.filename,
-            "mime_type": file.mime_type,
-            "size": file.size,
-            "download_url": download_url,
-        }
-
-
-__all__ = ["AgentFileDownloadRequestService", "FileDownloadRequestError"]
diff --git a/api/services/file_request_service.py b/api/services/file_request_service.py
index a795595d095..66b56684073 100644
--- a/api/services/file_request_service.py
+++ b/api/services/file_request_service.py
@@ -1,9 +1,9 @@
 """Service helpers for trusted file request control-plane endpoints.
 
-These helpers are used by inner APIs that return signed upload/download URLs to
-trusted external runtimes such as ``dify-agent``. They do not transfer file
-bytes themselves; they only rebuild access-scoped ``graphon.file.File`` values
-and resolve the signed URL that the caller should use directly.
+These helpers are used by inner APIs that allocate file access for trusted
+external runtimes. They rebuild access-scoped ``graphon.file.File`` values and
+return origin-free signed URIs so each transport adapter can select its own
+network origin without signing the file twice.
 """
 
 from __future__ import annotations
@@ -14,30 +14,32 @@ from typing import Any
 
 from core.app.entities.app_invoke_entities import InvokeFrom, UserFrom
 from core.app.file_access import DatabaseFileAccessController, FileAccessScope, bind_file_access_scope
+from core.app.workflow.file_runtime import DifyWorkflowFileRuntime
 from factories.file_factory.builders import build_from_mapping
 from graphon.file import File
-from graphon.file import helpers as file_helpers
 
 
 @dataclass(frozen=True, slots=True)
 class DownloadFileRequestResult:
-    """Resolved metadata and signed URL returned to trusted download callers."""
+    """Resolved metadata and signed URI returned to trusted download callers."""
 
     filename: str
     mime_type: str | None
     size: int
-    download_url: str
+    download_uri: str
 
 
 class FileRequestService:
-    """Resolve signed download URLs for trusted external file consumers."""
+    """Resolve signed download URIs for trusted external file consumers."""
 
     _access_controller: DatabaseFileAccessController
+    _runtime: DifyWorkflowFileRuntime
 
     def __init__(self, access_controller: DatabaseFileAccessController | None = None) -> None:
         self._access_controller = access_controller or DatabaseFileAccessController()
+        self._runtime = DifyWorkflowFileRuntime(file_access_controller=self._access_controller)
 
-    def request_download_url(
+    def request_download(
         self,
         *,
         tenant_id: str,
@@ -45,7 +47,6 @@ class FileRequestService:
         user_from: UserFrom | str,
         invoke_from: InvokeFrom | str,
         file_mapping: Mapping[str, Any],
-        for_external: bool = True,
     ) -> DownloadFileRequestResult:
         """Resolve one file mapping into signed download metadata.
 
@@ -62,15 +63,15 @@ class FileRequestService:
         )
         with bind_file_access_scope(scope):
             file = self._build_file(mapping=file_mapping, tenant_id=tenant_id)
-            download_url = file_helpers.resolve_file_url(file, for_external=for_external)
+            download_uri = self._runtime.resolve_file_uri(file=file)
 
-        if not download_url:
+        if not download_uri:
             raise ValueError("file does not support signed download")
         return DownloadFileRequestResult(
             filename=file.filename or "download.bin",
             mime_type=file.mime_type,
             size=file.size,
-            download_url=download_url,
+            download_uri=download_uri,
         )
 
     def _build_file(self, *, mapping: Mapping[str, Any], tenant_id: str) -> File:
diff --git a/api/tests/unit_tests/configs/test_dify_config.py b/api/tests/unit_tests/configs/test_dify_config.py
index f8e6e890eef..ce81057f006 100644
--- a/api/tests/unit_tests/configs/test_dify_config.py
+++ b/api/tests/unit_tests/configs/test_dify_config.py
@@ -202,6 +202,16 @@ def test_internal_files_url_prefers_explicit_value(monkeypatch: pytest.MonkeyPat
     assert config.INTERNAL_FILES_URL == "http://files-internal:5001"
 
 
+def test_empty_files_url_overrides_console_api_url_for_relative_browser_uris(monkeypatch: pytest.MonkeyPatch):
+    _clear_environment(monkeypatch)
+    monkeypatch.setenv("FILES_URL", "")
+    monkeypatch.setenv("CONSOLE_API_URL", "http://api:5001")
+
+    config = DifyConfig(_env_file=None)
+
+    assert config.FILES_URL == ""
+
+
 # NOTE: If there is a `.env` file in your Workspace, this test might not succeed as expected.
 # This is due to `pymilvus` loading all the variables from the `.env` file into `os.environ`.
 def test_flask_configs(monkeypatch: pytest.MonkeyPatch):
diff --git a/api/tests/unit_tests/controllers/inner_api/plugin/test_plugin.py b/api/tests/unit_tests/controllers/inner_api/plugin/test_plugin.py
index 249d8926124..c67e622ae51 100644
--- a/api/tests/unit_tests/controllers/inner_api/plugin/test_plugin.py
+++ b/api/tests/unit_tests/controllers/inner_api/plugin/test_plugin.py
@@ -263,11 +263,12 @@ class TestPluginUploadFileRequestApi:
         assert hasattr(api_instance, "post")
         assert callable(api_instance.post)
 
-    @patch("controllers.inner_api.plugin.plugin.get_signed_file_url_for_plugin")
-    def test_post_returns_signed_url(self, mock_get_url, api_instance, app: Flask):
+    @patch("controllers.inner_api.plugin.plugin.get_signed_file_uri_for_plugin")
+    def test_post_returns_signed_url(self, mock_get_uri, api_instance, app: Flask, monkeypatch: pytest.MonkeyPatch):
         """Test that post() generates a signed URL and returns it"""
         # Arrange
-        mock_get_url.return_value = "https://storage.example.com/signed-upload-url"
+        mock_get_uri.return_value = "/files/upload/for-plugin?sign=1"
+        monkeypatch.setattr(plugin_module.dify_config, "INTERNAL_FILES_URL", "http://api:5001")
         mock_tenant = MagicMock()
         mock_tenant.id = "tenant-id"
         mock_user = MagicMock()
@@ -282,14 +283,14 @@ class TestPluginUploadFileRequestApi:
         result = raw_post(api_instance, user_model=mock_user, tenant_model=mock_tenant, payload=mock_payload)
 
         # Assert
-        mock_get_url.assert_called_once_with(
+        mock_get_uri.assert_called_once_with(
             filename="test.pdf",
             mimetype="application/pdf",
             tenant_id="tenant-id",
             user_id="user-id",
             conversation_id="conversation-id",
         )
-        assert result["data"]["url"] == "https://storage.example.com/signed-upload-url"
+        assert result["data"]["url"] == "http://api:5001/files/upload/for-plugin?sign=1"
 
 
 class TestPluginDownloadFileRequestApi:
@@ -304,6 +305,13 @@ class TestPluginDownloadFileRequestApi:
         assert callable(api_instance.post)
 
     @pytest.mark.parametrize("sqlite_session", [(Tenant,)], indirect=True)
+    @pytest.mark.parametrize(
+        ("for_external", "expected_url"),
+        [
+            (True, "https://files.example.com/files/tools/report.pdf?sign=1"),
+            (False, "http://api:5001/files/tools/report.pdf?sign=1"),
+        ],
+    )
     @patch("controllers.inner_api.plugin.plugin.FileRequestService")
     def test_post_returns_signed_download_url(
         self,
@@ -312,6 +320,8 @@ class TestPluginDownloadFileRequestApi:
         app: Flask,
         monkeypatch: pytest.MonkeyPatch,
         sqlite_session: Session,
+        for_external: bool,
+        expected_url: str,
     ):
         tenant = Tenant(
             name="Plugin Tenant",
@@ -324,18 +334,20 @@ class TestPluginDownloadFileRequestApi:
         sqlite_session.commit()
         monkeypatch.setattr(plugin_module.db, "session", sqlite_session)
         mock_service = mock_service_cls.return_value
-        mock_service.request_download_url.return_value = MagicMock(
+        mock_service.request_download.return_value = MagicMock(
             filename="report.pdf",
             mime_type="application/pdf",
             size=123,
-            download_url="https://files.example.com/download",
+            download_uri="/files/tools/report.pdf?sign=1",
         )
+        monkeypatch.setattr(plugin_module.dify_config, "FILES_URL", "https://files.example.com")
+        monkeypatch.setattr(plugin_module.dify_config, "INTERNAL_FILES_URL", "http://api:5001")
         mock_payload = MagicMock()
         mock_payload.tenant_id = tenant.id
         mock_payload.user_id = "user-id"
         mock_payload.user_from = "account"
         mock_payload.invoke_from = "debugger"
-        mock_payload.for_external = False
+        mock_payload.for_external = for_external
         reference = build_file_reference(record_id="tool-file-1")
         mock_payload.file.model_dump.return_value = {
             "transfer_method": "tool_file",
@@ -345,19 +357,18 @@ class TestPluginDownloadFileRequestApi:
         raw_post = _extract_raw_post(PluginDownloadFileRequestApi)
         result = raw_post(api_instance, payload=mock_payload)
 
-        mock_service.request_download_url.assert_called_once_with(
+        mock_service.request_download.assert_called_once_with(
             tenant_id=tenant.id,
             user_id="user-id",
             user_from="account",
             invoke_from="debugger",
             file_mapping={"transfer_method": "tool_file", "reference": reference},
-            for_external=False,
         )
         assert result["data"] == {
             "filename": "report.pdf",
             "mime_type": "application/pdf",
             "size": 123,
-            "download_url": "https://files.example.com/download",
+            "download_url": expected_url,
         }
 
 
diff --git a/api/tests/unit_tests/controllers/inner_api/test_agent_files.py b/api/tests/unit_tests/controllers/inner_api/test_agent_files.py
new file mode 100644
index 00000000000..d01f9b5512f
--- /dev/null
+++ b/api/tests/unit_tests/controllers/inner_api/test_agent_files.py
@@ -0,0 +1,118 @@
+import inspect
+from collections.abc import Callable
+from types import SimpleNamespace
+from typing import cast
+from unittest.mock import MagicMock, patch
+
+import pytest
+from flask import Flask
+
+from controllers.inner_api.agent.files import AgentFileDownloadRequestApi, AgentFileUploadRequestApi
+from core.workflow.file_reference import build_file_reference
+from services.file_request_service import DownloadFileRequestResult
+
+MODULE = "controllers.inner_api.agent.files"
+
+
+def _raw[R](method: Callable[..., R]) -> Callable[..., R]:
+    return cast(Callable[..., R], inspect.unwrap(method))
+
+
+def test_upload_request_returns_origin_free_uri(app: Flask) -> None:
+    payload = {
+        "tenant_id": "tenant-1",
+        "user_id": "execution-user-1",
+        "filename": "report.pdf",
+        "mimetype": "application/pdf",
+        "conversation_id": "conversation-1",
+    }
+    tenant = SimpleNamespace(id="tenant-1")
+    user = SimpleNamespace(id="canonical-end-user-1")
+    session = MagicMock()
+    with app.test_request_context("/", method="POST", json=payload):
+        with (
+            patch(f"{MODULE}.TenantService") as tenant_service,
+            patch(f"{MODULE}.get_user", return_value=user),
+            patch(f"{MODULE}.get_signed_file_uri_for_plugin", return_value="/files/upload/for-plugin?sign=1") as sign,
+        ):
+            tenant_service.get_tenant_by_id.return_value = tenant
+            response = _raw(AgentFileUploadRequestApi.post)(AgentFileUploadRequestApi(), session)
+
+    assert response == {"upload_uri": "/files/upload/for-plugin?sign=1"}
+    tenant_service.get_tenant_by_id.assert_called_once_with("tenant-1", session=session)
+    sign.assert_called_once_with(
+        filename="report.pdf",
+        mimetype="application/pdf",
+        tenant_id="tenant-1",
+        user_id="canonical-end-user-1",
+        conversation_id="conversation-1",
+    )
+
+
+def test_download_request_returns_origin_free_uri_for_sandbox(app: Flask) -> None:
+    reference = build_file_reference(record_id="tool-file-1")
+    payload = {
+        "tenant_id": "tenant-1",
+        "user_id": "user-1",
+        "user_from": "account",
+        "invoke_from": "debugger",
+        "file": {"transfer_method": "tool_file", "reference": reference},
+        "for_frontend": False,
+    }
+    session = MagicMock()
+    with app.test_request_context("/", method="POST", json=payload):
+        with (
+            patch(f"{MODULE}.TenantService") as tenant_service,
+            patch(f"{MODULE}.FileRequestService") as service,
+        ):
+            tenant_service.get_tenant_by_id.return_value = MagicMock()
+            service.return_value.request_download.return_value = DownloadFileRequestResult(
+                filename="report.pdf",
+                mime_type="application/pdf",
+                size=123,
+                download_uri="/files/tools/tool-file-1.pdf?sign=1",
+            )
+            response = _raw(AgentFileDownloadRequestApi.post)(AgentFileDownloadRequestApi(), session)
+
+    assert response == {
+        "filename": "report.pdf",
+        "mime_type": "application/pdf",
+        "size": 123,
+        "download_uri": "/files/tools/tool-file-1.pdf?sign=1",
+    }
+    service.return_value.request_download.assert_called_once_with(
+        tenant_id="tenant-1",
+        user_id="user-1",
+        user_from="account",
+        invoke_from="debugger",
+        file_mapping={"transfer_method": "tool_file", "reference": reference},
+    )
+
+
+def test_download_request_binds_frontend_url(app: Flask, monkeypatch: pytest.MonkeyPatch) -> None:
+    reference = build_file_reference(record_id="tool-file-1")
+    payload = {
+        "tenant_id": "tenant-1",
+        "user_id": "user-1",
+        "user_from": "account",
+        "invoke_from": "debugger",
+        "file": {"transfer_method": "tool_file", "reference": reference},
+        "for_frontend": True,
+    }
+    monkeypatch.setattr(f"{MODULE}.dify_config.FILES_URL", "https://files.example.com")
+    session = MagicMock()
+    with app.test_request_context("/", method="POST", json=payload):
+        with (
+            patch(f"{MODULE}.TenantService") as tenant_service,
+            patch(f"{MODULE}.FileRequestService") as service,
+        ):
+            tenant_service.get_tenant_by_id.return_value = MagicMock()
+            service.return_value.request_download.return_value = DownloadFileRequestResult(
+                filename="report.pdf",
+                mime_type="application/pdf",
+                size=123,
+                download_uri="/files/tools/tool-file-1.pdf?sign=1",
+            )
+            response = _raw(AgentFileDownloadRequestApi.post)(AgentFileDownloadRequestApi(), session)
+
+    assert response["download_uri"] == "https://files.example.com/files/tools/tool-file-1.pdf?sign=1"
diff --git a/api/tests/unit_tests/core/app/workflow/test_file_runtime.py b/api/tests/unit_tests/core/app/workflow/test_file_runtime.py
index 22b6f0c72bf..02b4ad362ec 100644
--- a/api/tests/unit_tests/core/app/workflow/test_file_runtime.py
+++ b/api/tests/unit_tests/core/app/workflow/test_file_runtime.py
@@ -141,8 +141,9 @@ def test_resolve_file_url_requires_extension_for_tool_files() -> None:
 def test_resolve_file_url_uses_tool_signatures_for_tool_and_datasource_files(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    sign_tool_file = MagicMock(return_value="https://signed.example.com/file")
-    monkeypatch.setattr(file_runtime, "sign_tool_file", sign_tool_file)
+    sign_tool_file_uri = MagicMock(return_value="/files/signed")
+    monkeypatch.setattr(file_runtime, "sign_tool_file_uri", sign_tool_file_uri)
+    monkeypatch.setattr(file_runtime.dify_config, "FILES_URL", "https://files.example.com")
     runtime = _build_runtime()
 
     tool_file = _build_file(
@@ -156,9 +157,35 @@ def test_resolve_file_url_uses_tool_signatures_for_tool_and_datasource_files(
         extension=".png",
     )
 
-    assert runtime.resolve_file_url(file=tool_file) == "https://signed.example.com/file"
-    assert runtime.resolve_file_url(file=datasource_file) == "https://signed.example.com/file"
-    assert sign_tool_file.call_count == 2
+    assert runtime.resolve_file_url(file=tool_file) == "https://files.example.com/files/signed"
+    assert runtime.resolve_file_url(file=datasource_file) == "https://files.example.com/files/signed"
+    assert sign_tool_file_uri.call_count == 2
+
+
+def test_resolve_file_uri_keeps_dify_owned_file_origin_free(monkeypatch: pytest.MonkeyPatch) -> None:
+    sign_tool_file_uri = MagicMock(return_value="/files/tools/tool-file-id.png?sign=1")
+    monkeypatch.setattr(file_runtime, "sign_tool_file_uri", sign_tool_file_uri)
+    runtime = _build_runtime()
+    file = _build_file(
+        transfer_method=FileTransferMethod.TOOL_FILE,
+        reference=build_file_reference(record_id="tool-file-id"),
+        extension=".png",
+    )
+
+    assert runtime.resolve_file_uri(file=file) == "/files/tools/tool-file-id.png?sign=1"
+
+
+def test_resolve_file_url_returns_relative_uri_when_files_url_is_empty(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(file_runtime, "sign_tool_file_uri", lambda **_: "/files/tools/tool-file-id.png?sign=1")
+    monkeypatch.setattr(file_runtime.dify_config, "FILES_URL", "")
+    runtime = _build_runtime()
+    file = _build_file(
+        transfer_method=FileTransferMethod.TOOL_FILE,
+        reference=build_file_reference(record_id="tool-file-id"),
+        extension=".png",
+    )
+
+    assert runtime.resolve_file_url(file=file, for_external=True) == "/files/tools/tool-file-id.png?sign=1"
 
 
 def test_resolve_upload_file_url_signs_internal_urls_and_supports_attachments(
diff --git a/api/tests/unit_tests/core/tools/test_signature.py b/api/tests/unit_tests/core/tools/test_signature.py
index ee80cedd499..369c61455f8 100644
--- a/api/tests/unit_tests/core/tools/test_signature.py
+++ b/api/tests/unit_tests/core/tools/test_signature.py
@@ -7,14 +7,40 @@ from urllib.parse import parse_qs, urlparse
 import pytest
 
 from core.tools.signature import (
-    get_signed_file_url_for_plugin,
+    bind_file_uri,
+    get_signed_file_uri_for_plugin,
     sign_tool_file,
+    sign_tool_file_uri,
     sign_upload_file_preview_url,
     verify_plugin_file_signature,
     verify_tool_file_signature,
 )
 
 
+def test_bind_file_uri_uses_selected_base_and_preserves_remote_url() -> None:
+    uri = "/files/tools/tool-file-id.png?sign=1"
+
+    assert bind_file_uri(uri, "https://files.example.com") == f"https://files.example.com{uri}"
+    assert bind_file_uri(uri, "") == uri
+    assert bind_file_uri("https://remote.example.com/report.pdf", "https://files.example.com") == (
+        "https://remote.example.com/report.pdf"
+    )
+
+
+def test_sign_tool_file_uri_has_no_origin(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("core.tools.signature.time.time", lambda: 1700000000)
+    monkeypatch.setattr("core.tools.signature.os.urandom", lambda _: b"\x08" * 16)
+    monkeypatch.setattr("core.tools.signature.dify_config.SECRET_KEY", "unit-secret")
+
+    uri = sign_tool_file_uri("tool-file-id", ".png")
+    parsed = urlparse(uri)
+
+    assert parsed.scheme == ""
+    assert parsed.netloc == ""
+    assert parsed.path == "/files/tools/tool-file-id.png"
+    assert parse_qs(parsed.query)["timestamp"] == ["1700000000"]
+
+
 def test_sign_tool_file_and_verify_roundtrip(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr("core.tools.signature.time.time", lambda: 1700000000)
     monkeypatch.setattr("core.tools.signature.os.urandom", lambda _: b"\x01" * 16)
@@ -125,25 +151,23 @@ def test_sign_upload_file_preview_url_ignores_internal_files_url(monkeypatch: py
     assert query["sign"][0]
 
 
-def test_get_signed_file_url_for_plugin_and_verify_roundtrip(monkeypatch: pytest.MonkeyPatch) -> None:
+def test_get_signed_file_uri_for_plugin_and_verify_roundtrip(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr("core.tools.signature.time.time", lambda: 1700000000)
     monkeypatch.setattr("core.tools.signature.os.urandom", lambda _: b"\x06" * 16)
     monkeypatch.setattr("core.tools.signature.dify_config.SECRET_KEY", "unit-secret")
-    monkeypatch.setattr("core.tools.signature.dify_config.FILES_URL", "https://files.example.com")
-    monkeypatch.setattr("core.tools.signature.dify_config.INTERNAL_FILES_URL", "https://internal.example.com")
     monkeypatch.setattr("core.tools.signature.dify_config.FILES_ACCESS_TIMEOUT", 60)
 
-    url = get_signed_file_url_for_plugin(
+    uri = get_signed_file_uri_for_plugin(
         filename="report.pdf",
         mimetype="application/pdf",
         tenant_id="tenant-id",
         user_id="user-id",
         conversation_id="conversation-id",
     )
-    parsed = urlparse(url)
+    parsed = urlparse(uri)
     query = parse_qs(parsed.query)
 
-    assert parsed.netloc == "internal.example.com"
+    assert parsed.netloc == ""
     assert parsed.path == "/files/upload/for-plugin"
     assert query["tenant_id"] == ["tenant-id"]
     assert query["user_id"] == ["user-id"]
@@ -167,17 +191,15 @@ def test_verify_plugin_file_signature_rejects_invalid_signatures(monkeypatch: py
     monkeypatch.setattr("core.tools.signature.time.time", lambda: 1700000000)
     monkeypatch.setattr("core.tools.signature.os.urandom", lambda _: b"\x07" * 16)
     monkeypatch.setattr("core.tools.signature.dify_config.SECRET_KEY", "unit-secret")
-    monkeypatch.setattr("core.tools.signature.dify_config.FILES_URL", "https://files.example.com")
-    monkeypatch.setattr("core.tools.signature.dify_config.INTERNAL_FILES_URL", "")
     monkeypatch.setattr("core.tools.signature.dify_config.FILES_ACCESS_TIMEOUT", 30)
 
-    url = get_signed_file_url_for_plugin(
+    uri = get_signed_file_uri_for_plugin(
         filename="report.pdf",
         mimetype="application/pdf",
         tenant_id="tenant-id",
         user_id="user-id",
     )
-    query = parse_qs(urlparse(url).query)
+    query = parse_qs(urlparse(uri).query)
 
     assert (
         verify_plugin_file_signature(
diff --git a/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_runtime_request_builder.py b/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_runtime_request_builder.py
index f52bc63bdc1..36a4e9a5ee9 100644
--- a/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_runtime_request_builder.py
+++ b/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_runtime_request_builder.py
@@ -432,7 +432,7 @@ def test_builds_workflow_run_request_with_file_output_schema_and_reserved_metada
     assert "never invent the `reference` value" in output_description
     assert "Do not call `final_output` before the upload command succeeds" in output_description
     assert "accepted file-mapping shape and the returned `reference`" in output_description
-    assert "include the returned `download_url` in that reply" in output_description
+    assert "include the returned `public_download_url` in that reply" in output_description
     assert output_schema["properties"]["confidence"]["type"] == "number"
     assert output_schema["required"] == ["report"]
     assert layers[DIFY_AGENT_MODEL_LAYER_ID]["config"]["model_settings"] == {"temperature": 0.2}
diff --git a/api/tests/unit_tests/pyrefly.toml b/api/tests/unit_tests/pyrefly.toml
index 4a2f4e0e0da..d5db248382f 100644
--- a/api/tests/unit_tests/pyrefly.toml
+++ b/api/tests/unit_tests/pyrefly.toml
@@ -820,7 +820,6 @@ project-excludes = [
   "services/test_agent_app_sandbox_service.py",
   "services/test_agent_config_service.py",
   "services/test_agent_drive_service.py",
-  "services/test_agent_file_request_service.py",
   "services/test_annotation_service.py",
   "services/test_api_token_service.py",
   "services/test_app_generate_service.py",
diff --git a/api/tests/unit_tests/services/agent/test_prompt_mentions.py b/api/tests/unit_tests/services/agent/test_prompt_mentions.py
index 82c42a5bd86..48e4978a3bc 100644
--- a/api/tests/unit_tests/services/agent/test_prompt_mentions.py
+++ b/api/tests/unit_tests/services/agent/test_prompt_mentions.py
@@ -246,7 +246,7 @@ def test_node_job_resolver_resolves_each_kind(node_job: WorkflowNodeJobConfig):
         "Read START/tenders and produce qna_report (file output; create the file locally, run "
         "`dify-agent file upload <path>`, then set final_output.qna_report to a `tool_file` mapping "
         "using the returned `reference`; if replying to the user in natural language, use the returned "
-        "`download_url`; do not call final_output before upload succeeds, and do not use the local path, "
+        "`public_download_url`; do not call final_output before upload succeeds, and do not use the local path, "
         "filename, URL, or a synthesized dify-file-ref as the reference); "
         "if unsure contact EMAIL · David Hayes."
     )
diff --git a/api/tests/unit_tests/services/test_agent_file_request_service.py b/api/tests/unit_tests/services/test_agent_file_request_service.py
deleted file mode 100644
index c39e3f82558..00000000000
--- a/api/tests/unit_tests/services/test_agent_file_request_service.py
+++ /dev/null
@@ -1,105 +0,0 @@
-"""Unit tests for the Agent Files download-request service (ENG-592)."""
-
-from __future__ import annotations
-
-from types import SimpleNamespace
-from unittest.mock import patch
-
-import pytest
-
-from services.agent_file_request_service import AgentFileDownloadRequestService, FileDownloadRequestError
-
-_MOD = "services.agent_file_request_service"
-
-
-def _fake_file() -> SimpleNamespace:
-    return SimpleNamespace(filename="report.pdf", mime_type="application/pdf", size=12)
-
-
-def test_resolve_returns_metadata_and_internal_url():
-    with (
-        patch(f"{_MOD}.file_factory.build_from_mapping", return_value=_fake_file()) as build,
-        patch(f"{_MOD}.DifyWorkflowFileRuntime") as runtime_cls,
-    ):
-        runtime_cls.return_value.resolve_file_url.return_value = "http://internal/files/x?sign=1"
-        data = AgentFileDownloadRequestService.resolve(
-            tenant_id="tenant-1",
-            user_id="user-1",
-            user_from="account",
-            invoke_from="service-api",
-            file_mapping={"transfer_method": "tool_file", "reference": "tool-file-1"},
-        )
-
-    assert data == {
-        "filename": "report.pdf",
-        "mime_type": "application/pdf",
-        "size": 12,
-        "download_url": "http://internal/files/x?sign=1",
-    }
-    assert build.call_args.kwargs["tenant_id"] == "tenant-1"
-    # Sandbox/agent backend consumes the URL -> must be internal, not external.
-    assert runtime_cls.return_value.resolve_file_url.call_args.kwargs["for_external"] is False
-
-
-@pytest.mark.parametrize(
-    ("user_from", "invoke_from", "code"),
-    [
-        ("bogus", "service-api", "invalid_access_context"),
-        ("account", "not-a-source", "invalid_access_context"),
-    ],
-)
-def test_invalid_access_context_rejected(user_from: str, invoke_from: str, code: str):
-    with pytest.raises(FileDownloadRequestError) as exc_info:
-        AgentFileDownloadRequestService.resolve(
-            tenant_id="t",
-            user_id="u",
-            user_from=user_from,
-            invoke_from=invoke_from,
-            file_mapping={"transfer_method": "tool_file", "reference": "x"},
-        )
-    assert exc_info.value.status_code == 400
-    assert exc_info.value.code == code
-
-
-def test_missing_transfer_method_rejected():
-    with pytest.raises(FileDownloadRequestError) as exc_info:
-        AgentFileDownloadRequestService.resolve(
-            tenant_id="t",
-            user_id="u",
-            user_from="account",
-            invoke_from="service-api",
-            file_mapping={},
-        )
-    assert exc_info.value.status_code == 400
-    assert exc_info.value.code == "invalid_file_mapping"
-
-
-def test_inaccessible_file_maps_to_404():
-    with patch(f"{_MOD}.file_factory.build_from_mapping", side_effect=ValueError("ToolFile x not found")):
-        with pytest.raises(FileDownloadRequestError) as exc_info:
-            AgentFileDownloadRequestService.resolve(
-                tenant_id="t",
-                user_id="u",
-                user_from="end-user",
-                invoke_from="web-app",
-                file_mapping={"transfer_method": "tool_file", "reference": "x"},
-            )
-    assert exc_info.value.status_code == 404
-    assert exc_info.value.code == "file_not_accessible"
-
-
-def test_unresolved_url_maps_to_502():
-    with (
-        patch(f"{_MOD}.file_factory.build_from_mapping", return_value=_fake_file()),
-        patch(f"{_MOD}.DifyWorkflowFileRuntime") as runtime_cls,
-    ):
-        runtime_cls.return_value.resolve_file_url.return_value = None
-        with pytest.raises(FileDownloadRequestError) as exc_info:
-            AgentFileDownloadRequestService.resolve(
-                tenant_id="t",
-                user_id="u",
-                user_from="account",
-                invoke_from="service-api",
-                file_mapping={"transfer_method": "tool_file", "reference": "x"},
-            )
-    assert exc_info.value.status_code == 502
diff --git a/api/tests/unit_tests/services/test_file_request_service.py b/api/tests/unit_tests/services/test_file_request_service.py
index 3e2ea0a258a..9acfa38a026 100644
--- a/api/tests/unit_tests/services/test_file_request_service.py
+++ b/api/tests/unit_tests/services/test_file_request_service.py
@@ -15,7 +15,7 @@ from services.file_request_service import FileRequestService
         ("end-user", "service-api", UserFrom.END_USER, InvokeFrom.SERVICE_API),
     ],
 )
-def test_request_download_url_builds_file_under_bound_scope(
+def test_request_download_builds_file_under_bound_scope(
     user_from: UserFrom | str,
     invoke_from: InvokeFrom | str,
     expected_user_from: UserFrom,
@@ -29,12 +29,9 @@ def test_request_download_url_builds_file_under_bound_scope(
     with (
         patch("services.file_request_service.bind_file_access_scope", return_value=nullcontext()) as bind_scope,
         patch.object(service, "_build_file", return_value=fake_file) as build_file,
-        patch(
-            "services.file_request_service.file_helpers.resolve_file_url",
-            return_value="https://files.example.com/x",
-        ) as resolve_file_url,
+        patch.object(service._runtime, "resolve_file_uri", return_value="/files/tools/x?sign=1") as resolve_file_uri,
     ):
-        result = service.request_download_url(
+        result = service.request_download(
             tenant_id="tenant-1",
             user_id="user-1",
             user_from=user_from,
@@ -52,48 +49,23 @@ def test_request_download_url_builds_file_under_bound_scope(
     build_file.assert_called_once_with(
         mapping={"transfer_method": "tool_file", "reference": reference}, tenant_id="tenant-1"
     )
-    resolve_file_url.assert_called_once_with(fake_file, for_external=True)
+    resolve_file_uri.assert_called_once_with(file=fake_file)
     assert result.filename == "report.pdf"
     assert result.mime_type == "application/pdf"
     assert result.size == 123
-    assert result.download_url == "https://files.example.com/x"
+    assert result.download_uri == "/files/tools/x?sign=1"
 
 
-def test_request_download_url_supports_internal_download_urls() -> None:
-    fake_file = MagicMock(filename="report.pdf", mime_type="application/pdf", size=123)
-    service = FileRequestService(access_controller=MagicMock())
-
-    with (
-        patch("services.file_request_service.bind_file_access_scope", return_value=nullcontext()),
-        patch.object(service, "_build_file", return_value=fake_file),
-        patch(
-            "services.file_request_service.file_helpers.resolve_file_url",
-            return_value="http://internal-files/report.pdf",
-        ) as resolve_file_url,
-    ):
-        result = service.request_download_url(
-            tenant_id="tenant-1",
-            user_id="user-1",
-            user_from="account",
-            invoke_from="debugger",
-            file_mapping={"transfer_method": "tool_file", "reference": "dify-file-ref:tool-file-1"},
-            for_external=False,
-        )
-
-    resolve_file_url.assert_called_once_with(fake_file, for_external=False)
-    assert result.download_url == "http://internal-files/report.pdf"
-
-
-def test_request_download_url_rejects_unsupported_files() -> None:
+def test_request_download_rejects_unsupported_files() -> None:
     service = FileRequestService(access_controller=MagicMock())
 
     with (
         patch("services.file_request_service.bind_file_access_scope", return_value=nullcontext()),
         patch.object(service, "_build_file", return_value=MagicMock(filename="report.pdf", mime_type=None, size=1)),
-        patch("services.file_request_service.file_helpers.resolve_file_url", return_value=None),
+        patch.object(service._runtime, "resolve_file_uri", return_value=None),
     ):
         with pytest.raises(ValueError, match="file does not support signed download"):
-            service.request_download_url(
+            service.request_download(
                 tenant_id="tenant-1",
                 user_id="user-1",
                 user_from="account",
diff --git a/dify-agent-runtime/gen/dify/agent/stub/v1/agent_stub.pb.go b/dify-agent-runtime/gen/dify/agent/stub/v1/agent_stub.pb.go
index 4cfc11903d8..1d67854634a 100644
--- a/dify-agent-runtime/gen/dify/agent/stub/v1/agent_stub.pb.go
+++ b/dify-agent-runtime/gen/dify/agent/stub/v1/agent_stub.pb.go
@@ -292,7 +292,7 @@ func (x *FileMapping) GetUrl() string {
 type FileDownloadRequest struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	File          *FileMapping           `protobuf:"bytes,1,opt,name=file,proto3" json:"file,omitempty"`
-	ForExternal   *bool                  `protobuf:"varint,2,opt,name=for_external,json=forExternal,proto3,oneof" json:"for_external,omitempty"`
+	ForFrontend   *bool                  `protobuf:"varint,2,opt,name=for_frontend,json=forFrontend,proto3,oneof" json:"for_frontend,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
@@ -334,9 +334,9 @@ func (x *FileDownloadRequest) GetFile() *FileMapping {
 	return nil
 }
 
-func (x *FileDownloadRequest) GetForExternal() bool {
-	if x != nil && x.ForExternal != nil {
-		return *x.ForExternal
+func (x *FileDownloadRequest) GetForFrontend() bool {
+	if x != nil && x.ForFrontend != nil {
+		return *x.ForFrontend
 	}
 	return false
 }
@@ -436,8 +436,8 @@ const file_dify_agent_stub_v1_agent_stub_proto_rawDesc = "" +
 	"\x04_url\"\x83\x01\n" +
 	"\x13FileDownloadRequest\x123\n" +
 	"\x04file\x18\x01 \x01(\v2\x1f.dify.agent.stub.v1.FileMappingR\x04file\x12&\n" +
-	"\ffor_external\x18\x02 \x01(\bH\x00R\vforExternal\x88\x01\x01B\x0f\n" +
-	"\r_for_external\"\x99\x01\n" +
+	"\ffor_frontend\x18\x02 \x01(\bH\x00R\vforFrontend\x88\x01\x01B\x0f\n" +
+	"\r_for_frontend\"\x99\x01\n" +
 	"\x14FileDownloadResponse\x12\x1a\n" +
 	"\bfilename\x18\x01 \x01(\tR\bfilename\x12 \n" +
 	"\tmime_type\x18\x02 \x01(\tH\x00R\bmimeType\x88\x01\x01\x12\x12\n" +
diff --git a/dify-agent-runtime/internal/agentcli/client.go b/dify-agent-runtime/internal/agentcli/client.go
index 328386cdac1..ecc5feb94d9 100644
--- a/dify-agent-runtime/internal/agentcli/client.go
+++ b/dify-agent-runtime/internal/agentcli/client.go
@@ -8,7 +8,7 @@ type StubClient interface {
 	// Control-plane: available via gRPC or HTTP
 	Connect(ctx context.Context, argv []string, metadataJSON string) (*ConnectResponse, error)
 	CreateFileUploadURL(ctx context.Context, filename, mimetype string) (string, error)
-	CreateFileDownloadURL(ctx context.Context, transferMethod string, reference, url *string, forExternal bool) (*FileDownloadResponse, error)
+	CreateFileDownloadURL(ctx context.Context, transferMethod string, reference, url *string, forFrontend bool) (*FileDownloadResponse, error)
 
 	// Drive operations (HTTP-only control-plane)
 	GetDriveManifest(ctx context.Context, prefix string, includeDownloadURL bool) (*DriveManifestResponse, error)
diff --git a/dify-agent-runtime/internal/agentcli/client_grpc.go b/dify-agent-runtime/internal/agentcli/client_grpc.go
index 6a5f14b715d..ba6764b9d98 100644
--- a/dify-agent-runtime/internal/agentcli/client_grpc.go
+++ b/dify-agent-runtime/internal/agentcli/client_grpc.go
@@ -55,8 +55,8 @@ func (c *grpcStubClient) CreateFileUploadURL(ctx context.Context, filename, mime
 	return result.UploadURL, nil
 }
 
-func (c *grpcStubClient) CreateFileDownloadURL(ctx context.Context, transferMethod string, reference, url *string, forExternal bool) (*FileDownloadResponse, error) {
-	result, err := c.grpc.CreateFileDownload(ctx, transferMethod, reference, url, forExternal)
+func (c *grpcStubClient) CreateFileDownloadURL(ctx context.Context, transferMethod string, reference, url *string, forFrontend bool) (*FileDownloadResponse, error) {
+	result, err := c.grpc.CreateFileDownload(ctx, transferMethod, reference, url, forFrontend)
 	if err != nil {
 		return nil, err
 	}
diff --git a/dify-agent-runtime/internal/agentcli/client_http.go b/dify-agent-runtime/internal/agentcli/client_http.go
index 2a6031a54fd..c69c89b091a 100644
--- a/dify-agent-runtime/internal/agentcli/client_http.go
+++ b/dify-agent-runtime/internal/agentcli/client_http.go
@@ -72,7 +72,7 @@ func (c *httpStubClient) CreateFileUploadURL(_ context.Context, filename, mimety
 	return resp.UploadURL, nil
 }
 
-func (c *httpStubClient) CreateFileDownloadURL(_ context.Context, transferMethod string, reference, url *string, forExternal bool) (*FileDownloadResponse, error) {
+func (c *httpStubClient) CreateFileDownloadURL(_ context.Context, transferMethod string, reference, url *string, forFrontend bool) (*FileDownloadResponse, error) {
 	fileMapping := map[string]any{
 		"transfer_method": transferMethod,
 	}
@@ -85,7 +85,7 @@ func (c *httpStubClient) CreateFileDownloadURL(_ context.Context, transferMethod
 
 	payload := map[string]any{
 		"file":         fileMapping,
-		"for_external": forExternal,
+		"for_frontend": forFrontend,
 	}
 	body, statusCode, err := c.http.postJSON("/files/download-request", payload)
 	if err != nil {
diff --git a/dify-agent-runtime/internal/agentcli/file.go b/dify-agent-runtime/internal/agentcli/file.go
index d0f8ab75f1e..93dd3aabe83 100644
--- a/dify-agent-runtime/internal/agentcli/file.go
+++ b/dify-agent-runtime/internal/agentcli/file.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"mime"
 	"os"
 	"path/filepath"
@@ -12,9 +13,9 @@ import (
 
 // FileUploadResponse is the JSON output for `dify-agent file upload`.
 type FileUploadResponse struct {
-	TransferMethod string `json:"transfer_method"`
-	Reference      string `json:"reference"`
-	DownloadURL    string `json:"download_url"`
+	TransferMethod    string `json:"transfer_method"`
+	Reference         string `json:"reference"`
+	PublicDownloadURL string `json:"public_download_url"`
 }
 
 // FileDownloadResponse is the response from a file download request.
@@ -27,6 +28,27 @@ type FileDownloadResponse struct {
 
 // RunFileUpload executes the `file upload` command.
 func RunFileUpload(env *Environment, path string) error {
+	client, err := NewStubClient(env)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = client.Close() }()
+
+	return runFileUpload(client, path, os.Stdout)
+}
+
+type fileUploadClient interface {
+	CreateFileUploadURL(ctx context.Context, filename, mimetype string) (string, error)
+	UploadFileToURL(uploadURL, filePath, filename, mimetype string) ([]byte, error)
+	CreateFileDownloadURL(
+		ctx context.Context,
+		transferMethod string,
+		reference, url *string,
+		forFrontend bool,
+	) (*FileDownloadResponse, error)
+}
+
+func runFileUpload(client fileUploadClient, path string, output io.Writer) error {
 	absPath, err := filepath.Abs(path)
 	if err != nil {
 		return fmt.Errorf("resolve path: %w", err)
@@ -40,12 +62,6 @@ func RunFileUpload(env *Environment, path string) error {
 	mimetype := guessMIMEType(filename)
 	ctx := context.Background()
 
-	client, err := NewStubClient(env)
-	if err != nil {
-		return err
-	}
-	defer func() { _ = client.Close() }()
-
 	// Step 1: Request a signed upload URL
 	uploadURL, err := client.CreateFileUploadURL(ctx, filename, mimetype)
 	if err != nil {
@@ -70,18 +86,18 @@ func RunFileUpload(env *Environment, path string) error {
 
 	// Step 3: Request download URL for the uploaded file
 	ref := reference
-	dlResp, err := client.CreateFileDownloadURL(ctx, "tool_file", &ref, nil, false)
+	dlResp, err := client.CreateFileDownloadURL(ctx, "tool_file", &ref, nil, true)
 	if err != nil {
 		return err
 	}
 
 	result := FileUploadResponse{
-		TransferMethod: "tool_file",
-		Reference:      reference,
-		DownloadURL:    dlResp.DownloadURL,
+		TransferMethod:    "tool_file",
+		Reference:         reference,
+		PublicDownloadURL: dlResp.DownloadURL,
 	}
 	out, _ := json.Marshal(result)
-	fmt.Println(string(out))
+	_, _ = fmt.Fprintln(output, string(out))
 	return nil
 }
 
diff --git a/dify-agent-runtime/internal/agentcli/file_test.go b/dify-agent-runtime/internal/agentcli/file_test.go
new file mode 100644
index 00000000000..a76fcffb7f5
--- /dev/null
+++ b/dify-agent-runtime/internal/agentcli/file_test.go
@@ -0,0 +1,110 @@
+package agentcli
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+type fakeFileUploadClient struct {
+	forFrontend bool
+}
+
+func (f *fakeFileUploadClient) CreateFileUploadURL(_ context.Context, filename, mimetype string) (string, error) {
+	return "https://sandbox-files.example.com/files/upload/for-plugin?sign=1", nil
+}
+
+func (f *fakeFileUploadClient) UploadFileToURL(uploadURL, filePath, filename, mimetype string) ([]byte, error) {
+	return []byte(`{"reference":"dify-file-ref:canonical"}`), nil
+}
+
+func (f *fakeFileUploadClient) CreateFileDownloadURL(
+	_ context.Context,
+	_ string,
+	_, _ *string,
+	forFrontend bool,
+) (*FileDownloadResponse, error) {
+	f.forFrontend = forFrontend
+	return &FileDownloadResponse{
+		Filename:    "report.pdf",
+		MimeType:    "application/pdf",
+		Size:        123,
+		DownloadURL: "/files/tools/report.pdf?sign=2",
+	}, nil
+}
+
+func TestRunFileUploadReturnsFrontendDisplayURL(t *testing.T) {
+	filePath := t.TempDir() + "/report.pdf"
+	if err := os.WriteFile(filePath, []byte("report"), 0o600); err != nil {
+		t.Fatalf("write fixture: %v", err)
+	}
+
+	client := &fakeFileUploadClient{}
+	var output bytes.Buffer
+	if err := runFileUpload(client, filePath, &output); err != nil {
+		t.Fatalf("run file upload: %v", err)
+	}
+
+	if !client.forFrontend {
+		t.Fatal("download request did not select frontend display URL")
+	}
+	got := strings.TrimSpace(output.String())
+	want := `{"transfer_method":"tool_file","reference":"dify-file-ref:canonical","public_download_url":"/files/tools/report.pdf?sign=2"}`
+	if got != want {
+		t.Fatalf("output = %s, want %s", got, want)
+	}
+}
+
+func TestRunFileDownloadRequestsSandboxURLAndWritesFile(t *testing.T) {
+	var requestPayload map[string]json.RawMessage
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/agent-stub/files/download-request":
+			if err := json.NewDecoder(r.Body).Decode(&requestPayload); err != nil {
+				t.Errorf("decode download request: %v", err)
+				http.Error(w, "bad request", http.StatusBadRequest)
+				return
+			}
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = w.Write([]byte(`{"filename":"report.pdf","mime_type":"application/pdf","size":6,"download_url":"` + server.URL + `/files/report.pdf"}`))
+		case "/files/report.pdf":
+			_, _ = w.Write([]byte("report"))
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer server.Close()
+
+	targetDir := t.TempDir()
+	err := RunFileDownload(
+		&Environment{URL: server.URL + "/agent-stub", AuthJWE: "test-token"},
+		"tool_file",
+		"dify-file-ref:canonical",
+		targetDir,
+	)
+	if err != nil {
+		t.Fatalf("run file download: %v", err)
+	}
+
+	var forFrontend bool
+	if err := json.Unmarshal(requestPayload["for_frontend"], &forFrontend); err != nil {
+		t.Fatalf("decode for_frontend: %v", err)
+	}
+	if forFrontend {
+		t.Fatal("download request selected a frontend URL")
+	}
+	data, err := os.ReadFile(filepath.Join(targetDir, "report.pdf"))
+	if err != nil {
+		t.Fatalf("read downloaded file: %v", err)
+	}
+	if string(data) != "report" {
+		t.Fatalf("downloaded file = %q, want report", data)
+	}
+}
diff --git a/dify-agent-runtime/internal/stubclient/client.go b/dify-agent-runtime/internal/stubclient/client.go
index d9b6bdddc8a..9c3c0a659b1 100644
--- a/dify-agent-runtime/internal/stubclient/client.go
+++ b/dify-agent-runtime/internal/stubclient/client.go
@@ -113,7 +113,7 @@ type FileDownloadResult struct {
 }
 
 // CreateFileDownload requests a download URL from the Agent Stub server.
-func (c *Client) CreateFileDownload(ctx context.Context, transferMethod string, reference, url *string, forExternal bool) (*FileDownloadResult, error) {
+func (c *Client) CreateFileDownload(ctx context.Context, transferMethod string, reference, url *string, forFrontend bool) (*FileDownloadResult, error) {
 	ctx, cancel := context.WithTimeout(ctx, c.timeout)
 	defer cancel()
 
@@ -129,7 +129,7 @@ func (c *Client) CreateFileDownload(ctx context.Context, transferMethod string,
 
 	resp, err := c.stub.CreateFileDownloadRequest(ctx, &stubv1.FileDownloadRequest{
 		File:        fileMapping,
-		ForExternal: &forExternal,
+		ForFrontend: &forFrontend,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("stubclient: file download: %w", err)
diff --git a/dify-agent/docs/dify-agent/get-started/index.md b/dify-agent/docs/dify-agent/get-started/index.md
index bcad90cf144..b672c5fdb41 100644
--- a/dify-agent/docs/dify-agent/get-started/index.md
+++ b/dify-agent/docs/dify-agent/get-started/index.md
@@ -99,7 +99,8 @@ the request's product context;
 `DifyRuntimeLayerConfig.backend_binding_ref` carries only that opaque ref and
 opens a new operation-scoped `RuntimeLease` for the run. When shell jobs need to
 call back with the `dify-agent` command, also set
-`DIFY_AGENT_STUB_API_BASE_URL`. The supplied default configs include a
+`DIFY_AGENT_STUB_API_BASE_URL` and the Sandbox-reachable Dify API base
+`DIFY_AGENT_SANDBOX_FILES_BASE_URL`. The supplied default configs include a
 development `DIFY_AGENT_SERVER_SECRET_KEY`, but production deployments should
 override it with a unique 32-byte base64url value as documented in
 `.example.env`.
diff --git a/dify-agent/docs/dify-agent/guide/index.md b/dify-agent/docs/dify-agent/guide/index.md
index 129568a5643..3ff80e1e28f 100644
--- a/dify-agent/docs/dify-agent/guide/index.md
+++ b/dify-agent/docs/dify-agent/guide/index.md
@@ -56,7 +56,8 @@ also reads `.env` and `dify-agent/.env` when present.
 | `DIFY_AGENT_E2B_SHELLCTL_PORT` | `5004` | shellctl port exposed by the E2B template. |
 | `DIFY_AGENT_SANDBOX_FILE_UPLOAD_MAX_BYTES` | `52428800` | Standalone Dify Agent maximum for whole-file Workspace upload capture; 50 MiB by default. Docker Compose derives it from `PLUGIN_MAX_FILE_SIZE`. |
 | `DIFY_AGENT_SHELL_REDACT_PATTERNS` | empty | JSON array of additional regex patterns redacted from Shell output. |
-| `DIFY_AGENT_STUB_API_BASE_URL` | empty | Public Agent Stub API base URL reachable from shellctl-managed remote machines. HTTP may be the service root or `/agent-stub`; gRPC must be `grpc://host:port`. Enables `DIFY_AGENT_STUB_*` env injection for user `shell.run` jobs. |
+| `DIFY_AGENT_STUB_API_BASE_URL` | empty | Agent Stub API base URL reachable from the Sandbox. HTTP may be the service root or `/agent-stub`; gRPC must be `grpc://host:port`. Enables `DIFY_AGENT_STUB_*` env injection for user `shell.run` jobs. |
+| `DIFY_AGENT_SANDBOX_FILES_BASE_URL` | empty | Dify API base URL reachable from the Sandbox for signed `/files/*` upload/download bytes. Required when Agent Stub file operations are enabled. May include an ingress path prefix, but not a query or fragment. |
 | `DIFY_AGENT_STUB_GRPC_BIND_ADDRESS` | empty | Optional `host:port` bind override used only when `DIFY_AGENT_STUB_API_BASE_URL` uses `grpc://`. |
 | `DIFY_AGENT_SERVER_SECRET_KEY` | empty | Security-sensitive server-wide root secret used to derive the JWE encryption key for Agent Stub bearer tokens; required when `DIFY_AGENT_STUB_API_BASE_URL` is set. The supplied default config uses a development value; set a unique unpadded base64url 32-byte secret in production. |
 | `DIFY_AGENT_OUTBOUND_HTTP_CONNECT_TIMEOUT` | `10` | Shared outbound HTTP connect timeout in seconds. |
@@ -87,12 +88,30 @@ DIFY_AGENT_LOCAL_SANDBOX_WORKSPACE_ROOT=/tmp/dify-agent/workspaces
 DIFY_AGENT_LOCAL_SANDBOX_HOME_SNAPSHOT_ROOT=/tmp/dify-agent/home-snapshots
 DIFY_AGENT_SANDBOX_FILE_UPLOAD_MAX_BYTES=52428800
 DIFY_AGENT_STUB_API_BASE_URL=https://agent.example.com/agent-stub
+DIFY_AGENT_SANDBOX_FILES_BASE_URL=https://dify.example.com
 # This is security-sensitive: it derives the JWE encryption key for Agent Stub bearer tokens.
 # Replace this development default in production.
 # Generate one with: python -c 'import secrets; print(secrets.token_urlsafe(32))'
 DIFY_AGENT_SERVER_SECRET_KEY=MDEyMzQ1Njc4OWFiY2RlZjAxMjM0NTY3ODlhYmNkZWY
 ```
 
+The two Sandbox-facing base URLs have different owners. Agent Stub control
+requests use `DIFY_AGENT_STUB_API_BASE_URL`; signed file bytes use
+`DIFY_AGENT_SANDBOX_FILES_BASE_URL`. `DIFY_AGENT_INNER_API_URL` remains a
+trusted service-to-service URL and is never returned to the Sandbox.
+
+For a remote Sandbox, expose only `/agent-stub/*` from Agent Backend and the
+existing `/files/*` Dify API data plane. The `/files/*` ingress must preserve
+the complete signed query string, allow the configured upload body size, and
+use response streaming and timeouts suitable for large downloads. Do not expose
+Agent Backend `/runs`, Workspace, or Binding management routes through the
+Sandbox ingress.
+
+Browser presentation URLs are independent. Configure Dify API `FILES_URL` to a
+browser-reachable public origin, or leave it empty so responses use same-origin
+relative `/files/...` URIs. Never set `FILES_URL` to a Docker-only service name
+such as `http://api:5001`.
+
 `DIFY_AGENT_SHELLCTL_ENTRYPOINT` and `DIFY_AGENT_SHELLCTL_AUTH_TOKEN` remain
 accepted only as legacy aliases for the two Local settings. New deployments
 must use `DIFY_AGENT_LOCAL_SANDBOX_ENDPOINT` and
diff --git a/dify-agent/docs/dify-agent/user-manual/shell-layer/index.md b/dify-agent/docs/dify-agent/user-manual/shell-layer/index.md
index 188add6cfc3..0f1d923ffea 100644
--- a/dify-agent/docs/dify-agent/user-manual/shell-layer/index.md
+++ b/dify-agent/docs/dify-agent/user-manual/shell-layer/index.md
@@ -80,16 +80,40 @@ DIFY_AGENT_LOCAL_SANDBOX_AUTH_TOKEN=replace-with-shellctl-token
 The auth token may be empty when shellctl authentication is disabled. E2B uses
 `DIFY_AGENT_E2B_API_KEY`, the prepared template, and its shellctl settings.
 
-To let shell jobs call the Agent Stub with `dify-agent ...`, configure a public
-Agent Stub URL and a unique production secret:
+To let shell jobs call the Agent Stub with `dify-agent ...`, configure a
+Sandbox-reachable Agent Stub URL and a unique production secret. Remote
+deployments normally use a public Agent ingress. Local Compose uses
+`http://agent_backend:5050/agent-stub`, reached through the existing
+`agent_ssrf_proxy`; this configuration does not change the Compose network
+topology.
 
 ```env
 DIFY_AGENT_STUB_API_BASE_URL=https://agent.example.com/agent-stub
+DIFY_AGENT_SANDBOX_FILES_BASE_URL=https://dify.example.com
 DIFY_AGENT_SERVER_SECRET_KEY=replace-with-unpadded-base64url-for-32-random-bytes
 ```
 
 HTTP URLs may be either the service root or the explicit `/agent-stub` root.
-The server normalizes a service root and rejects unrelated paths.
+The server normalizes a service root and rejects unrelated paths. The separate
+Sandbox file base must point to the Dify API ingress serving `/files/*`; it is
+used for CLI upload/download bytes even when Agent Stub control calls use gRPC.
+
+After `dify-agent file upload <path>` succeeds, the CLI prints JSON such as:
+
+```json
+{
+  "transfer_method": "tool_file",
+  "reference": "dify-file-ref:...",
+  "public_download_url": "https://dify.example.com/files/tools/..."
+}
+```
+
+`reference` is the persistent canonical file identity and should be stored in
+structured output. `public_download_url` is a short-lived frontend presentation
+address: it is an absolute URL when Dify API `FILES_URL` has a public origin,
+or a same-origin `/files/...` relative URI when `FILES_URL` is empty. The CLI
+does not access this field. The former ambiguous `download_url` upload-output
+key is now named `public_download_url`.
 
 ## Request graph
 
diff --git a/dify-agent/proto/dify/agent/stub/v1/agent_stub.proto b/dify-agent/proto/dify/agent/stub/v1/agent_stub.proto
index 608d6d0006c..fddd165feba 100644
--- a/dify-agent/proto/dify/agent/stub/v1/agent_stub.proto
+++ b/dify-agent/proto/dify/agent/stub/v1/agent_stub.proto
@@ -38,7 +38,7 @@ message FileMapping {
 
 message FileDownloadRequest {
   FileMapping file = 1;
-  optional bool for_external = 2;
+  optional bool for_frontend = 2;
 }
 
 message FileDownloadResponse {
diff --git a/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.py b/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.py
index db940989607..3b43456bf94 100644
--- a/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.py
+++ b/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.py
@@ -20,14 +20,15 @@ _sym_db = _symbol_database.Default()
 
 
 DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(
-    b'\n#dify/agent/stub/v1/agent_stub.proto\x12\x12\x64ify.agent.stub.v1"O\n\x0e\x43onnectRequest\x12\x18\n\x10protocol_version\x18\x01 \x01(\x05\x12\x0c\n\x04\x61rgv\x18\x02 \x03(\t\x12\x15\n\rmetadata_json\x18\x03 \x01(\t"8\n\x0f\x43onnectResponse\x12\x15\n\rconnection_id\x18\x01 \x01(\t\x12\x0e\n\x06status\x18\x02 \x01(\t"7\n\x11\x46ileUploadRequest\x12\x10\n\x08\x66ilename\x18\x01 \x01(\t\x12\x10\n\x08mimetype\x18\x02 \x01(\t"(\n\x12\x46ileUploadResponse\x12\x12\n\nupload_url\x18\x01 \x01(\t"f\n\x0b\x46ileMapping\x12\x17\n\x0ftransfer_method\x18\x01 \x01(\t\x12\x16\n\treference\x18\x02 \x01(\tH\x00\x88\x01\x01\x12\x10\n\x03url\x18\x03 \x01(\tH\x01\x88\x01\x01\x42\x0c\n\n_referenceB\x06\n\x04_url"p\n\x13\x46ileDownloadRequest\x12-\n\x04\x66ile\x18\x01 \x01(\x0b\x32\x1f.dify.agent.stub.v1.FileMapping\x12\x19\n\x0c\x66or_external\x18\x02 \x01(\x08H\x00\x88\x01\x01\x42\x0f\n\r_for_external"r\n\x14\x46ileDownloadResponse\x12\x10\n\x08\x66ilename\x18\x01 \x01(\t\x12\x16\n\tmime_type\x18\x02 \x01(\tH\x00\x88\x01\x01\x12\x0c\n\x04size\x18\x03 \x01(\x03\x12\x14\n\x0c\x64ownload_url\x18\x04 \x01(\tB\x0c\n\n_mime_type2\xc0\x02\n\x10\x41gentStubService\x12R\n\x07\x43onnect\x12".dify.agent.stub.v1.ConnectRequest\x1a#.dify.agent.stub.v1.ConnectResponse\x12h\n\x17\x43reateFileUploadRequest\x12%.dify.agent.stub.v1.FileUploadRequest\x1a&.dify.agent.stub.v1.FileUploadResponse\x12n\n\x19\x43reateFileDownloadRequest\x12\'.dify.agent.stub.v1.FileDownloadRequest\x1a(.dify.agent.stub.v1.FileDownloadResponseb\x06proto3'
+    b'\n#dify/agent/stub/v1/agent_stub.proto\x12\x12\x64ify.agent.stub.v1"O\n\x0e\x43onnectRequest\x12\x18\n\x10protocol_version\x18\x01 \x01(\x05\x12\x0c\n\x04\x61rgv\x18\x02 \x03(\t\x12\x15\n\rmetadata_json\x18\x03 \x01(\t"8\n\x0f\x43onnectResponse\x12\x15\n\rconnection_id\x18\x01 \x01(\t\x12\x0e\n\x06status\x18\x02 \x01(\t"7\n\x11\x46ileUploadRequest\x12\x10\n\x08\x66ilename\x18\x01 \x01(\t\x12\x10\n\x08mimetype\x18\x02 \x01(\t"(\n\x12\x46ileUploadResponse\x12\x12\n\nupload_url\x18\x01 \x01(\t"f\n\x0b\x46ileMapping\x12\x17\n\x0ftransfer_method\x18\x01 \x01(\t\x12\x16\n\treference\x18\x02 \x01(\tH\x00\x88\x01\x01\x12\x10\n\x03url\x18\x03 \x01(\tH\x01\x88\x01\x01\x42\x0c\n\n_referenceB\x06\n\x04_url"p\n\x13\x46ileDownloadRequest\x12-\n\x04\x66ile\x18\x01 \x01(\x0b\x32\x1f.dify.agent.stub.v1.FileMapping\x12\x19\n\x0c\x66or_frontend\x18\x02 \x01(\x08H\x00\x88\x01\x01\x42\x0f\n\r_for_frontend"r\n\x14\x46ileDownloadResponse\x12\x10\n\x08\x66ilename\x18\x01 \x01(\t\x12\x16\n\tmime_type\x18\x02 \x01(\tH\x00\x88\x01\x01\x12\x0c\n\x04size\x18\x03 \x01(\x03\x12\x14\n\x0c\x64ownload_url\x18\x04 \x01(\tB\x0c\n\n_mime_type2\xc0\x02\n\x10\x41gentStubService\x12R\n\x07\x43onnect\x12".dify.agent.stub.v1.ConnectRequest\x1a#.dify.agent.stub.v1.ConnectResponse\x12h\n\x17\x43reateFileUploadRequest\x12%.dify.agent.stub.v1.FileUploadRequest\x1a&.dify.agent.stub.v1.FileUploadResponse\x12n\n\x19\x43reateFileDownloadRequest\x12\'.dify.agent.stub.v1.FileDownloadRequest\x1a(.dify.agent.stub.v1.FileDownloadResponseB\x1bZ\x19\x64ify/agent/stub/v1;stubv1b\x06proto3'
 )
 
 _globals = globals()
 _builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
 _builder.BuildTopDescriptorsAndMessages(DESCRIPTOR, "dify.agent.stub.v1.agent_stub_pb2", _globals)
 if not _descriptor._USE_C_DESCRIPTORS:
-    DESCRIPTOR._loaded_options = None
+    _globals["DESCRIPTOR"]._loaded_options = None
+    _globals["DESCRIPTOR"]._serialized_options = b"Z\031dify/agent/stub/v1;stubv1"
     _globals["_CONNECTREQUEST"]._serialized_start = 59
     _globals["_CONNECTREQUEST"]._serialized_end = 138
     _globals["_CONNECTRESPONSE"]._serialized_start = 140
diff --git a/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.pyi b/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.pyi
index 617956bd845..9f05ba759e5 100644
--- a/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.pyi
+++ b/dify-agent/src/dify_agent/agent_stub/grpc/_generated/agent_stub_pb2.pyi
@@ -49,12 +49,12 @@ class FileMapping(_message.Message):
     def __init__(self, transfer_method: _Optional[str] = ..., reference: _Optional[str] = ..., url: _Optional[str] = ...) -> None: ...
 
 class FileDownloadRequest(_message.Message):
-    __slots__ = ("file", "for_external")
+    __slots__ = ("file", "for_frontend")
     FILE_FIELD_NUMBER: _ClassVar[int]
-    FOR_EXTERNAL_FIELD_NUMBER: _ClassVar[int]
+    FOR_FRONTEND_FIELD_NUMBER: _ClassVar[int]
     file: FileMapping
-    for_external: bool
-    def __init__(self, file: _Optional[_Union[FileMapping, _Mapping]] = ..., for_external: _Optional[bool] = ...) -> None: ...
+    for_frontend: bool
+    def __init__(self, file: _Optional[_Union[FileMapping, _Mapping]] = ..., for_frontend: _Optional[bool] = ...) -> None: ...
 
 class FileDownloadResponse(_message.Message):
     __slots__ = ("filename", "mime_type", "size", "download_url")
diff --git a/dify-agent/src/dify_agent/agent_stub/grpc/conversions.py b/dify-agent/src/dify_agent/agent_stub/grpc/conversions.py
index a79e446c85e..72e5642c46e 100644
--- a/dify-agent/src/dify_agent/agent_stub/grpc/conversions.py
+++ b/dify-agent/src/dify_agent/agent_stub/grpc/conversions.py
@@ -101,7 +101,7 @@ def file_download_request_from_proto(message: agent_stub_pb2.FileDownloadRequest
     return AgentStubFileDownloadRequest.model_validate(
         {
             "file": file_mapping_kwargs,
-            "for_external": message.for_external if message.HasField("for_external") else True,
+            "for_frontend": message.for_frontend if message.HasField("for_frontend") else True,
         }
     )
 
@@ -110,7 +110,7 @@ def proto_file_download_request(
     pb2_module,
     *,
     file: AgentStubFileMapping,
-    for_external: bool = True,
+    for_frontend: bool = True,
 ) -> agent_stub_pb2.FileDownloadRequest:
     """Build one protobuf file-download request from the public DTO."""
     mapping = pb2_module.FileMapping(transfer_method=file.transfer_method)
@@ -119,7 +119,7 @@ def proto_file_download_request(
     if file.url is not None:
         mapping.url = file.url
     request = pb2_module.FileDownloadRequest(file=mapping)
-    request.for_external = for_external
+    request.for_frontend = for_frontend
     return request
 
 
diff --git a/dify-agent/src/dify_agent/agent_stub/protocol/agent_stub.py b/dify-agent/src/dify_agent/agent_stub/protocol/agent_stub.py
index 734ca50d53e..2287117bea3 100644
--- a/dify-agent/src/dify_agent/agent_stub/protocol/agent_stub.py
+++ b/dify-agent/src/dify_agent/agent_stub/protocol/agent_stub.py
@@ -15,7 +15,7 @@ from dataclasses import dataclass
 from typing import ClassVar, Final, Literal
 from urllib.parse import urlsplit, urlunsplit
 
-from pydantic import BaseModel, ConfigDict, Field, JsonValue, model_validator
+from pydantic import AliasChoices, BaseModel, ConfigDict, Field, JsonValue, model_validator
 
 from dify_agent.agent_stub._constants import AGENT_STUB_DRIVE_BASE_ENV_VAR, DEFAULT_AGENT_STUB_DRIVE_BASE
 
@@ -246,10 +246,19 @@ class AgentStubFileMapping(BaseModel):
 
 
 class AgentStubFileDownloadRequest(BaseModel):
-    """Request body for one signed download URL allocation."""
+    """Request one file URL for a specific consumer audience.
+
+    ``for_frontend=True`` allocates a frontend-display URL that the CLI only
+    returns to its caller. ``False`` allocates a Sandbox byte-transfer URL that
+    the CLI immediately fetches. The deprecated HTTP input name
+    ``for_external`` remains accepted for one compatibility cycle.
+    """
 
     file: AgentStubFileMapping
-    for_external: bool = True
+    for_frontend: bool = Field(
+        default=True,
+        validation_alias=AliasChoices("for_frontend", "for_external"),
+    )
 
     model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")
 
diff --git a/dify-agent/src/dify_agent/agent_stub/server/agent_stub_files.py b/dify-agent/src/dify_agent/agent_stub/server/agent_stub_files.py
index 59cd43b6bb5..541f5f62400 100644
--- a/dify-agent/src/dify_agent/agent_stub/server/agent_stub_files.py
+++ b/dify-agent/src/dify_agent/agent_stub/server/agent_stub_files.py
@@ -14,11 +14,12 @@ from __future__ import annotations
 
 from collections.abc import Mapping
 from dataclasses import dataclass
+import posixpath
 from typing import Any, Protocol
-from urllib.parse import urljoin
+from urllib.parse import unquote, urlsplit
 
 import httpx
-from pydantic import BaseModel, ConfigDict, ValidationError
+from pydantic import ValidationError
 
 from dify_agent.agent_stub.protocol.agent_stub import (
     AgentStubFileDownloadRequest,
@@ -71,36 +72,28 @@ class AgentStubFileRequestError(RuntimeError):
         super().__init__(str(detail))
 
 
-class _BackwardsInvocationEnvelope(BaseModel):
-    """Minimal parser for Dify API plugin-style inner API envelopes."""
-
-    data: object | None = None
-    error: str | None = None
-
-    model_config = ConfigDict(extra="ignore")
-
-
 @dataclass(slots=True)
 class DifyApiAgentStubFileRequestHandler:
     """Call Dify API inner file request endpoints on behalf of the sandbox.
 
-    The upload path calls ``/inner/api/upload/file/request`` and injects the
+    The upload path calls ``/inner/api/agent/files/upload-request`` and injects the
     authenticated execution context's ``tenant_id``, ``user_id``, and optional
     ``conversation_id`` along with the requested filename and mimetype. The download path calls
-    ``/inner/api/download/file/request`` and injects ``tenant_id``,
+    ``/inner/api/agent/files/download-request`` and injects ``tenant_id``,
     ``user_id``, ``user_from``, and ``invoke_from`` plus the validated public
     file mapping.
 
     ``user_id`` is mandatory for both operations. Missing user context is
     rejected before any network call with ``AgentStubFileRequestError(400, ...)``.
-    Timeouts, transport failures, non-2xx responses, invalid JSON, invalid
-    plugin-style envelopes, and invalid success schemas are all normalized into
+    Timeouts, transport failures, non-2xx responses, invalid JSON, and invalid
+    success schemas are all normalized into
     ``AgentStubFileRequestError`` so the stub routes can preserve a stable HTTP
     contract without exposing raw ``httpx`` or Pydantic exceptions.
     """
 
     inner_api_url: str
     inner_api_key: str
+    sandbox_files_base_url: str
     timeout: httpx.Timeout | float = 30.0
 
     async def create_upload_request(
@@ -119,7 +112,7 @@ class DifyApiAgentStubFileRequestHandler:
         Raises:
             AgentStubFileRequestError: when user context is incomplete, the
                 inner API times out or fails, the response is non-2xx, or the
-                success payload does not contain a non-empty ``url`` string.
+                success payload does not contain a valid ``upload_uri``.
         """
         execution_context = self._require_user_context(principal.execution_context)
         payload = {
@@ -129,12 +122,12 @@ class DifyApiAgentStubFileRequestHandler:
             "mimetype": request.mimetype,
             "conversation_id": execution_context.conversation_id,
         }
-        data = await self._post_inner_api("/inner/api/upload/file/request", payload)
-        upload_url = data.get("url")
-        if not isinstance(upload_url, str) or not upload_url:
-            raise AgentStubFileRequestError(502, "Dify API upload request response is missing url")
+        data = await self._post_inner_api("/inner/api/agent/files/upload-request", payload)
+        upload_uri = data.get("upload_uri")
+        if not isinstance(upload_uri, str) or not upload_uri:
+            raise AgentStubFileRequestError(502, "Dify API upload request response is missing upload_uri")
         return AgentStubFileUploadResponse(
-            upload_url=urljoin(f"{self.inner_api_url.rstrip('/')}/", upload_url),
+            upload_url=self._bind_sandbox_files_base_url(upload_uri),
         )
 
     async def create_download_request(
@@ -153,8 +146,7 @@ class DifyApiAgentStubFileRequestHandler:
         Raises:
             AgentStubFileRequestError: when user context is incomplete, the
                 inner API times out or fails, the response is non-2xx, the
-                plugin-style envelope is malformed, or the success payload does
-                not match ``AgentStubFileDownloadResponse``.
+                success payload does not contain safe download metadata.
         """
         execution_context = self._require_user_context(principal.execution_context)
         payload: dict[str, object] = {
@@ -164,11 +156,14 @@ class DifyApiAgentStubFileRequestHandler:
             "invoke_from": execution_context.invoke_from,
             "file": request.file.model_dump(mode="json", exclude_none=True),
         }
-        if request.for_external is False:
-            payload["for_external"] = False
-        data = await self._post_inner_api("/inner/api/download/file/request", payload)
+        payload["for_frontend"] = request.for_frontend
+        data = await self._post_inner_api("/inner/api/agent/files/download-request", payload)
+        download_uri = data.get("download_uri")
+        if not isinstance(download_uri, str) or not download_uri:
+            raise AgentStubFileRequestError(502, "Dify API download request response is missing download_uri")
+        download_url = self._resolve_download_url(request=request, download_uri=download_uri)
         try:
-            return AgentStubFileDownloadResponse.model_validate(data)
+            return AgentStubFileDownloadResponse.model_validate({**data, "download_url": download_url})
         except ValidationError as exc:
             raise AgentStubFileRequestError(502, "Dify API download request response is invalid") from exc
 
@@ -197,15 +192,46 @@ class DifyApiAgentStubFileRequestHandler:
         if response.is_error:
             detail = raw_payload.get("detail", raw_payload) if isinstance(raw_payload, dict) else raw_payload
             raise AgentStubFileRequestError(response.status_code, detail)
-        try:
-            envelope = _BackwardsInvocationEnvelope.model_validate(raw_payload)
-        except ValidationError as exc:
-            raise AgentStubFileRequestError(502, "Dify API file request response is invalid") from exc
-        if envelope.error:
-            raise AgentStubFileRequestError(400, envelope.error)
-        if not isinstance(envelope.data, dict):
-            raise AgentStubFileRequestError(502, "Dify API file request response is missing data")
-        return dict(envelope.data)
+        if not isinstance(raw_payload, dict):
+            raise AgentStubFileRequestError(502, "Dify API file request response is invalid")
+        return raw_payload
+
+    def _resolve_download_url(self, *, request: AgentStubFileDownloadRequest, download_uri: str) -> str:
+        if request.file.transfer_method == "remote_url":
+            if self._is_absolute_http_url(download_uri):
+                return download_uri
+            raise AgentStubFileRequestError(502, "Dify API returned an invalid remote download URL")
+
+        if request.for_frontend:
+            if self._is_absolute_http_url(download_uri) or self._is_safe_dify_file_uri(download_uri):
+                return download_uri
+            raise AgentStubFileRequestError(502, "Dify API returned an unsafe frontend download URI")
+
+        return self._bind_sandbox_files_base_url(download_uri)
+
+    def _bind_sandbox_files_base_url(self, uri: str) -> str:
+        if not self._is_safe_dify_file_uri(uri):
+            raise AgentStubFileRequestError(502, "Dify API returned an unsafe Dify file URI")
+        return f"{self.sandbox_files_base_url.rstrip('/')}{uri}"
+
+    @staticmethod
+    def _is_absolute_http_url(value: str) -> bool:
+        parsed = urlsplit(value)
+        return parsed.scheme in {"http", "https"} and bool(parsed.netloc)
+
+    @staticmethod
+    def _is_safe_dify_file_uri(value: str) -> bool:
+        parsed = urlsplit(value)
+        if parsed.scheme or parsed.netloc or parsed.fragment or value.startswith("//"):
+            return False
+
+        decoded_path = parsed.path
+        for _ in range(2):
+            decoded_path = unquote(decoded_path)
+        if "\\" in decoded_path:
+            return False
+        normalized_path = posixpath.normpath(decoded_path)
+        return decoded_path.startswith("/files/") and normalized_path.startswith("/files/")
 
     @staticmethod
     def _parse_json(response: httpx.Response) -> object:
diff --git a/dify-agent/src/dify_agent/layers/_agent_file_cli_help.py b/dify-agent/src/dify_agent/layers/_agent_file_cli_help.py
index 50deef3d851..cbe19a27bbe 100644
--- a/dify-agent/src/dify_agent/layers/_agent_file_cli_help.py
+++ b/dify-agent/src/dify_agent/layers/_agent_file_cli_help.py
@@ -3,5 +3,5 @@
 AGENT_FILE_UPLOAD_REPLY_HINT = (
     "When you want to provide a generated or sandbox-local file to the user in a "
     "natural-language reply, run the installed CLI command `dify-agent file upload PATH` and include the returned "
-    "`download_url` so the user can open or download the file."
+    "`public_download_url` so the user can open or download the file."
 )
diff --git a/dify-agent/src/dify_agent/server/settings.py b/dify-agent/src/dify_agent/server/settings.py
index 37ad32f37ac..c8e388f275a 100644
--- a/dify-agent/src/dify_agent/server/settings.py
+++ b/dify-agent/src/dify_agent/server/settings.py
@@ -74,6 +74,10 @@ class ServerSettings(BaseSettings):
     e2b_shellctl_port: int = Field(default=5004, ge=1, le=65535)
     sandbox_file_upload_max_bytes: int = Field(default=50 * 1024 * 1024, ge=1)
     agent_stub_api_base_url: str | None = Field(default=None, validation_alias="DIFY_AGENT_STUB_API_BASE_URL")
+    sandbox_files_base_url: str | None = Field(
+        default=None,
+        validation_alias="DIFY_AGENT_SANDBOX_FILES_BASE_URL",
+    )
     agent_stub_grpc_bind_address: str | None = Field(default=None, validation_alias="DIFY_AGENT_STUB_GRPC_BIND_ADDRESS")
     server_secret_key: str | None = None
     api_token: str | None = None
@@ -107,6 +111,22 @@ class ServerSettings(BaseSettings):
             return normalize_agent_stub_api_base_url(validated)
         return normalize_agent_stub_api_base_url(stripped)
 
+    @field_validator("sandbox_files_base_url")
+    @classmethod
+    def normalize_sandbox_files_base_url_value(cls, value: str | None) -> str | None:
+        """Normalize the Dify API base URL reachable from the Sandbox."""
+
+        if value is None:
+            return None
+        stripped = value.strip()
+        if not stripped:
+            return None
+        validated = str(TypeAdapter(AnyHttpUrl).validate_python(stripped))
+        parsed = validated.rstrip("/")
+        if "?" in parsed or "#" in parsed:
+            raise ValueError("DIFY_AGENT_SANDBOX_FILES_BASE_URL must not include a query string or fragment")
+        return parsed
+
     @field_validator("agent_stub_grpc_bind_address")
     @classmethod
     def normalize_agent_stub_grpc_bind_address_value(cls, value: str | None) -> str | None:
@@ -169,6 +189,14 @@ class ServerSettings(BaseSettings):
         """Require Agent Stub settings while allowing deployments without inner API calls."""
         if self.agent_stub_api_base_url is not None and self.server_secret_key is None:
             raise ValueError("DIFY_AGENT_SERVER_SECRET_KEY is required when DIFY_AGENT_STUB_API_BASE_URL is set.")
+        if (
+            self.agent_stub_api_base_url is not None
+            and self.inner_api_key is not None
+            and self.sandbox_files_base_url is None
+        ):
+            raise ValueError(
+                "DIFY_AGENT_SANDBOX_FILES_BASE_URL is required when Agent Stub file operations are enabled."
+            )
         if self.agent_stub_grpc_bind_address is not None:
             if self.agent_stub_api_base_url is None:
                 raise ValueError(
@@ -209,12 +237,14 @@ class ServerSettings(BaseSettings):
         return AgentStubTokenCodec.from_server_secret(self.server_secret_key)
 
     def create_agent_stub_file_request_handler(self) -> DifyApiAgentStubFileRequestHandler | None:
-        """Return the Dify API file bridge when both Dify API settings are configured."""
-        if self.inner_api_key is None:
+        """Return the file bridge when inner API and Sandbox data-plane settings are configured."""
+        if self.inner_api_key is None or self.sandbox_files_base_url is None:
             return None
         return DifyApiAgentStubFileRequestHandler(
             inner_api_url=self.inner_api_url,
             inner_api_key=self.inner_api_key,
+            sandbox_files_base_url=self.sandbox_files_base_url,
+            timeout=self.create_outbound_http_timeout(),
         )
 
     def create_agent_stub_config_request_handler(self) -> DifyApiAgentStubConfigRequestHandler | None:
diff --git a/dify-agent/src/dify_agent/server/workspace_files.py b/dify-agent/src/dify_agent/server/workspace_files.py
index 26e963f1092..6e6863fa035 100644
--- a/dify-agent/src/dify_agent/server/workspace_files.py
+++ b/dify-agent/src/dify_agent/server/workspace_files.py
@@ -114,7 +114,7 @@ class AgentStubWorkspaceFileUploader:
             mapping = AgentStubFileMapping(transfer_method="tool_file", reference=payload.reference)
             download_request = await self.file_request_handler.create_download_request(
                 principal=principal,
-                request=AgentStubFileDownloadRequest(file=mapping, for_external=False),
+                request=AgentStubFileDownloadRequest(file=mapping, for_frontend=False),
             )
             return WorkspaceUploadedFile(
                 reference=payload.reference,
diff --git a/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_agent_stub_protocol.py b/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_agent_stub_protocol.py
index 0c16cf8bccf..45413319717 100644
--- a/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_agent_stub_protocol.py
+++ b/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_agent_stub_protocol.py
@@ -12,6 +12,7 @@ from dify_agent.agent_stub.protocol.agent_stub import (
     AgentStubDriveCommitRequest,
     AgentStubDriveFileRef,
     AgentStubDriveManifestResponse,
+    AgentStubFileDownloadRequest,
     AgentStubFileMapping,
     agent_stub_connections_url,
     agent_stub_drive_base_for_ref,
@@ -150,6 +151,21 @@ def test_agent_stub_file_mapping_rejects_remote_url_with_reference() -> None:
         )
 
 
+def test_agent_stub_file_download_request_accepts_legacy_http_audience_alias() -> None:
+    mapping = {"transfer_method": "tool_file", "reference": _reference("tool-file-1")}
+
+    request = AgentStubFileDownloadRequest.model_validate({"file": mapping, "for_external": False})
+
+    assert request.for_frontend is False
+    assert request.model_dump() == {
+        "file": {"transfer_method": "tool_file", "reference": _reference("tool-file-1"), "url": None},
+        "for_frontend": False,
+    }
+
+    with pytest.raises(ValidationError):
+        _ = AgentStubFileDownloadRequest.model_validate({"file": mapping, "for_frontend": True, "for_external": False})
+
+
 def test_agent_stub_drive_commit_request_validates_file_refs() -> None:
     request = AgentStubDriveCommitRequest(
         items=[
diff --git a/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_grpc_conversions.py b/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_grpc_conversions.py
index 8c061254151..504ecccc857 100644
--- a/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_grpc_conversions.py
+++ b/dify-agent/tests/local/dify_agent/agent_stub/protocol/test_grpc_conversions.py
@@ -53,32 +53,33 @@ def test_file_download_request_from_proto_respects_optional_reference() -> None:
 
     assert request.file.reference == _reference("tool-file-1")
     assert request.file.url is None
-    assert request.for_external is True
+    assert request.for_frontend is True
 
 
-def test_file_download_request_from_proto_preserves_explicit_internal_audience() -> None:
+def test_file_download_request_from_proto_preserves_explicit_sandbox_transfer_audience() -> None:
     message = agent_stub_pb2.FileDownloadRequest(
         file=agent_stub_pb2.FileMapping(
             transfer_method="tool_file",
             reference=_reference("tool-file-1"),
         ),
-        for_external=False,
+        for_frontend=False,
     )
 
     request = file_download_request_from_proto(message)
 
-    assert request.for_external is False
+    assert request.for_frontend is False
 
 
 def test_proto_file_download_request_preserves_selected_audience() -> None:
     message = proto_file_download_request(
         agent_stub_pb2,
         file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1")),
-        for_external=False,
+        for_frontend=False,
     )
 
-    assert message.HasField("for_external") is True
-    assert message.for_external is False
+    assert message.HasField("for_frontend") is True
+    assert message.for_frontend is False
+    assert agent_stub_pb2.FileDownloadRequest.DESCRIPTOR.fields_by_name["for_frontend"].number == 2
 
 
 def test_connect_request_from_proto_rejects_invalid_metadata_json() -> None:
diff --git a/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_app.py b/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_app.py
index e683a7ea6db..8206a466e87 100644
--- a/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_app.py
+++ b/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_app.py
@@ -64,6 +64,7 @@ def test_create_agent_stub_app_wires_configured_file_handler_for_upload_requests
         server_secret_key=_base64url_secret(b"1" * 32),
         inner_api_url="https://api.example.com",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="https://files.example.com",
     )
     token_codec = settings.create_agent_stub_token_codec()
     assert token_codec is not None
@@ -72,9 +73,9 @@ def test_create_agent_stub_app_wires_configured_file_handler_for_upload_requests
     original_async_client = httpx.AsyncClient
 
     def handler(request: httpx.Request) -> httpx.Response:
-        assert str(request.url) == "https://api.example.com/inner/api/upload/file/request"
+        assert str(request.url) == "https://api.example.com/inner/api/agent/files/upload-request"
         assert request.headers["X-Inner-Api-Key"] == "inner-secret"
-        return httpx.Response(200, json={"data": {"url": "https://files.example.com/upload"}})
+        return httpx.Response(200, json={"upload_uri": "/files/upload/for-plugin?sign=1"})
 
     monkeypatch.setattr(
         "dify_agent.agent_stub.server.agent_stub_files.httpx.AsyncClient",
@@ -89,7 +90,7 @@ def test_create_agent_stub_app_wires_configured_file_handler_for_upload_requests
     )
 
     assert response.status_code == 200
-    assert response.json() == {"upload_url": "https://files.example.com/upload"}
+    assert response.json() == {"upload_url": "https://files.example.com/files/upload/for-plugin?sign=1"}
 
 
 def test_create_agent_stub_app_wires_configured_drive_handler_for_manifest_requests(monkeypatch) -> None:
@@ -98,6 +99,7 @@ def test_create_agent_stub_app_wires_configured_drive_handler_for_manifest_reque
         server_secret_key=_base64url_secret(b"1" * 32),
         inner_api_url="https://api.example.com",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="https://files.example.com",
     )
     token_codec = settings.create_agent_stub_token_codec()
     assert token_codec is not None
diff --git a/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_files.py b/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_files.py
index 8782ba48af0..6fae0a6d0dd 100644
--- a/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_files.py
+++ b/dify-agent/tests/local/dify_agent/agent_stub/server/test_agent_stub_files.py
@@ -5,6 +5,7 @@ import base64
 import json
 
 import httpx
+import pytest
 
 from dify_agent.agent_stub.protocol.agent_stub import (
     AgentStubFileDownloadRequest,
@@ -33,7 +34,7 @@ def _principal() -> AgentStubPrincipal:
     )
 
 
-def _patch_async_client(monkeypatch, handler) -> None:
+def _patch_async_client(monkeypatch: pytest.MonkeyPatch, handler) -> None:
     original_async_client = httpx.AsyncClient
     monkeypatch.setattr(
         "dify_agent.agent_stub.server.agent_stub_files.httpx.AsyncClient",
@@ -41,14 +42,22 @@ def _patch_async_client(monkeypatch, handler) -> None:
     )
 
 
+def _file_handler(*, sandbox_files_base_url: str = "https://sandbox-files.example.com/dify"):
+    return DifyApiAgentStubFileRequestHandler(
+        inner_api_url="https://api.internal.example.com",
+        inner_api_key="inner-secret",
+        sandbox_files_base_url=sandbox_files_base_url,
+    )
+
+
 def _reference(record_id: str) -> str:
     payload = base64.urlsafe_b64encode(json.dumps({"record_id": record_id}, separators=(",", ":")).encode()).decode()
     return f"dify-file-ref:{payload}"
 
 
-def test_dify_api_agent_stub_file_handler_injects_execution_context_for_upload(monkeypatch) -> None:
+def test_upload_request_uses_agent_inner_endpoint_and_binds_sandbox_base(monkeypatch: pytest.MonkeyPatch) -> None:
     def handler(request: httpx.Request) -> httpx.Response:
-        assert str(request.url) == "https://api.example.com/inner/api/upload/file/request"
+        assert str(request.url) == "https://api.internal.example.com/inner/api/agent/files/upload-request"
         assert request.headers["X-Inner-Api-Key"] == "inner-secret"
         assert json.loads(request.content) == {
             "tenant_id": "tenant-1",
@@ -57,240 +66,220 @@ def test_dify_api_agent_stub_file_handler_injects_execution_context_for_upload(m
             "mimetype": "application/pdf",
             "conversation_id": "conversation-1",
         }
-        return httpx.Response(200, json={"data": {"url": "https://files.example.com/upload"}})
+        return httpx.Response(200, json={"upload_uri": "/files/upload/for-plugin?signed=yes"})
 
     _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
 
     async def scenario() -> None:
-        response = await file_handler.create_upload_request(
+        response = await _file_handler().create_upload_request(
             principal=_principal(),
             request=AgentStubFileUploadRequest(filename="report.pdf", mimetype="application/pdf"),
         )
-        assert response.upload_url == "https://files.example.com/upload"
+        assert response.upload_url == "https://sandbox-files.example.com/dify/files/upload/for-plugin?signed=yes"
 
     asyncio.run(scenario())
 
 
-def test_dify_api_agent_stub_file_handler_resolves_relative_upload_url(monkeypatch) -> None:
-    def handler(_request: httpx.Request) -> httpx.Response:
-        return httpx.Response(200, json={"data": {"url": "/files/upload/for-plugin?signed=yes"}})
+def test_sandbox_download_request_binds_origin_free_uri(monkeypatch: pytest.MonkeyPatch) -> None:
+    reference = _reference("tool-file-1")
 
-    _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
-
-    async def scenario() -> None:
-        response = await file_handler.create_upload_request(
-            principal=_principal(),
-            request=AgentStubFileUploadRequest(filename="report.pdf", mimetype="application/pdf"),
-        )
-        assert response.upload_url == "https://api.example.com/files/upload/for-plugin?signed=yes"
-
-    asyncio.run(scenario())
-
-
-def test_dify_api_agent_stub_file_handler_injects_execution_context_for_download(monkeypatch) -> None:
     def handler(request: httpx.Request) -> httpx.Response:
-        assert str(request.url) == "https://api.example.com/inner/api/download/file/request"
+        assert str(request.url) == "https://api.internal.example.com/inner/api/agent/files/download-request"
         assert json.loads(request.content) == {
             "tenant_id": "tenant-1",
             "user_id": "user-1",
             "user_from": "account",
             "invoke_from": "service-api",
-            "file": {"transfer_method": "tool_file", "reference": _reference("tool-file-1")},
+            "file": {"transfer_method": "tool_file", "reference": reference},
+            "for_frontend": False,
         }
         return httpx.Response(
             200,
             json={
-                "data": {
-                    "filename": "report.pdf",
-                    "mime_type": "application/pdf",
-                    "size": 123,
-                    "download_url": "https://files.example.com/download",
-                }
+                "filename": "report.pdf",
+                "mime_type": "application/pdf",
+                "size": 123,
+                "download_uri": "/files/tools/tool-file-1.pdf?sign=1",
             },
         )
 
     _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
 
     async def scenario() -> None:
-        response = await file_handler.create_download_request(
+        response = await _file_handler().create_download_request(
             principal=_principal(),
             request=AgentStubFileDownloadRequest(
-                file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1"))
+                file=AgentStubFileMapping(transfer_method="tool_file", reference=reference),
+                for_frontend=False,
             ),
         )
-        assert response.download_url == "https://files.example.com/download"
+        assert response.download_url == "https://sandbox-files.example.com/dify/files/tools/tool-file-1.pdf?sign=1"
 
     asyncio.run(scenario())
 
 
-def test_dify_api_agent_stub_file_handler_forwards_internal_download_audience(monkeypatch) -> None:
+@pytest.mark.parametrize(
+    "download_uri",
+    [
+        "https://dify.example.com/files/tools/tool-file-1.pdf?sign=1",
+        "/files/tools/tool-file-1.pdf?sign=1",
+    ],
+)
+def test_frontend_download_request_preserves_public_or_relative_uri(
+    monkeypatch: pytest.MonkeyPatch,
+    download_uri: str,
+) -> None:
     def handler(request: httpx.Request) -> httpx.Response:
-        assert str(request.url) == "https://api.example.com/inner/api/download/file/request"
-        assert json.loads(request.content)["for_external"] is False
+        assert json.loads(request.content)["for_frontend"] is True
         return httpx.Response(
             200,
-            json={
-                "data": {
-                    "filename": "report.pdf",
-                    "mime_type": "application/pdf",
-                    "size": 123,
-                    "download_url": "http://internal-files/report.pdf",
-                }
-            },
+            json={"filename": "report.pdf", "mime_type": "application/pdf", "size": 123, "download_uri": download_uri},
         )
 
     _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
 
     async def scenario() -> None:
-        response = await file_handler.create_download_request(
+        response = await _file_handler().create_download_request(
             principal=_principal(),
             request=AgentStubFileDownloadRequest(
                 file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1")),
-                for_external=False,
+                for_frontend=True,
             ),
         )
-        assert response.download_url == "http://internal-files/report.pdf"
+        assert response.download_url == download_uri
 
     asyncio.run(scenario())
 
 
-def test_dify_api_agent_stub_file_handler_rejects_missing_user_id() -> None:
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
+def test_remote_download_url_is_never_rewritten(monkeypatch: pytest.MonkeyPatch) -> None:
+    remote_url = "https://remote.example.com/report.pdf"
+
+    def handler(_request: httpx.Request) -> httpx.Response:
+        return httpx.Response(
+            200,
+            json={"filename": "report.pdf", "mime_type": "application/pdf", "size": 123, "download_uri": remote_url},
+        )
+
+    _patch_async_client(monkeypatch, handler)
+
+    async def scenario() -> None:
+        response = await _file_handler().create_download_request(
+            principal=_principal(),
+            request=AgentStubFileDownloadRequest(
+                file=AgentStubFileMapping(transfer_method="remote_url", url=remote_url),
+                for_frontend=False,
+            ),
+        )
+        assert response.download_url == remote_url
+
+    asyncio.run(scenario())
+
+
+def test_remote_download_rejects_relative_uri_for_frontend_audience(monkeypatch: pytest.MonkeyPatch) -> None:
+    def handler(_request: httpx.Request) -> httpx.Response:
+        return httpx.Response(
+            200,
+            json={"filename": "report.pdf", "mime_type": "application/pdf", "size": 123, "download_uri": "/files/x"},
+        )
+
+    _patch_async_client(monkeypatch, handler)
+
+    async def scenario() -> None:
+        with pytest.raises(AgentStubFileRequestError, match="invalid remote download URL"):
+            await _file_handler().create_download_request(
+                principal=_principal(),
+                request=AgentStubFileDownloadRequest(
+                    file=AgentStubFileMapping(
+                        transfer_method="remote_url", url="https://remote.example.com/report.pdf"
+                    ),
+                    for_frontend=True,
+                ),
+            )
+
+    asyncio.run(scenario())
+
+
+@pytest.mark.parametrize(
+    "unsafe_uri",
+    [
+        "//attacker.example/files/x",
+        "/files/../admin",
+        "/files/%252e%252e/admin",
+        "http://api:5001/files/tools/x",
+        "/not-files/x",
+    ],
+)
+def test_sandbox_download_rejects_unsafe_dify_file_uri(
+    monkeypatch: pytest.MonkeyPatch,
+    unsafe_uri: str,
+) -> None:
+    def handler(_request: httpx.Request) -> httpx.Response:
+        return httpx.Response(
+            200,
+            json={"filename": "x", "mime_type": None, "size": 1, "download_uri": unsafe_uri},
+        )
+
+    _patch_async_client(monkeypatch, handler)
+
+    async def scenario() -> None:
+        with pytest.raises(AgentStubFileRequestError, match="unsafe Dify file URI"):
+            await _file_handler().create_download_request(
+                principal=_principal(),
+                request=AgentStubFileDownloadRequest(
+                    file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1")),
+                    for_frontend=False,
+                ),
+            )
+
+    asyncio.run(scenario())
+
+
+def test_handler_rejects_missing_execution_user_before_network() -> None:
     principal = _principal()
     principal.execution_context = principal.execution_context.model_copy(update={"user_id": None})
 
     async def scenario() -> None:
-        try:
-            await file_handler.create_upload_request(
+        with pytest.raises(AgentStubFileRequestError, match="user_id"):
+            await _file_handler().create_upload_request(
                 principal=principal,
                 request=AgentStubFileUploadRequest(filename="report.pdf", mimetype="application/pdf"),
             )
-        except AgentStubFileRequestError as exc:
-            assert "user_id" in str(exc)
-        else:
-            raise AssertionError("expected AgentStubFileRequestError")
 
     asyncio.run(scenario())
 
 
-def test_dify_api_agent_stub_file_handler_maps_non_2xx_response(monkeypatch) -> None:
+def test_handler_preserves_inner_api_error_status(monkeypatch: pytest.MonkeyPatch) -> None:
     def handler(_request: httpx.Request) -> httpx.Response:
         return httpx.Response(403, json={"detail": "forbidden"})
 
     _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
 
     async def scenario() -> None:
-        try:
-            await file_handler.create_upload_request(
+        with pytest.raises(AgentStubFileRequestError) as exc_info:
+            await _file_handler().create_upload_request(
                 principal=_principal(),
                 request=AgentStubFileUploadRequest(filename="report.pdf", mimetype="application/pdf"),
             )
-        except AgentStubFileRequestError as exc:
-            assert exc.status_code == 403
-            assert exc.detail == "forbidden"
-        else:
-            raise AssertionError("expected AgentStubFileRequestError")
+        assert exc_info.value.status_code == 403
+        assert exc_info.value.detail == "forbidden"
 
     asyncio.run(scenario())
 
 
-def test_dify_api_agent_stub_file_handler_maps_error_envelope(monkeypatch) -> None:
+def test_handler_rejects_missing_download_uri(monkeypatch: pytest.MonkeyPatch) -> None:
     def handler(_request: httpx.Request) -> httpx.Response:
-        return httpx.Response(200, json={"error": "bad request"})
+        return httpx.Response(200, json={"filename": "report.pdf", "size": 1})
 
     _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
 
     async def scenario() -> None:
-        try:
-            await file_handler.create_download_request(
+        with pytest.raises(AgentStubFileRequestError, match="missing download_uri"):
+            await _file_handler().create_download_request(
                 principal=_principal(),
                 request=AgentStubFileDownloadRequest(
-                    file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1"))
+                    file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1")),
+                    for_frontend=False,
                 ),
             )
-        except AgentStubFileRequestError as exc:
-            assert exc.status_code == 400
-            assert exc.detail == "bad request"
-        else:
-            raise AssertionError("expected AgentStubFileRequestError")
-
-    asyncio.run(scenario())
-
-
-def test_dify_api_agent_stub_file_handler_rejects_upload_response_missing_url(monkeypatch) -> None:
-    def handler(_request: httpx.Request) -> httpx.Response:
-        return httpx.Response(200, json={"data": {}})
-
-    _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
-
-    async def scenario() -> None:
-        try:
-            await file_handler.create_upload_request(
-                principal=_principal(),
-                request=AgentStubFileUploadRequest(filename="report.pdf", mimetype="application/pdf"),
-            )
-        except AgentStubFileRequestError as exc:
-            assert exc.status_code == 502
-            assert exc.detail == "Dify API upload request response is missing url"
-        else:
-            raise AssertionError("expected AgentStubFileRequestError")
-
-    asyncio.run(scenario())
-
-
-def test_dify_api_agent_stub_file_handler_rejects_invalid_download_response_schema(monkeypatch) -> None:
-    def handler(_request: httpx.Request) -> httpx.Response:
-        return httpx.Response(200, json={"data": {"filename": "report.pdf"}})
-
-    _patch_async_client(monkeypatch, handler)
-    file_handler = DifyApiAgentStubFileRequestHandler(
-        inner_api_url="https://api.example.com",
-        inner_api_key="inner-secret",
-    )
-
-    async def scenario() -> None:
-        try:
-            await file_handler.create_download_request(
-                principal=_principal(),
-                request=AgentStubFileDownloadRequest(
-                    file=AgentStubFileMapping(transfer_method="tool_file", reference=_reference("tool-file-1"))
-                ),
-            )
-        except AgentStubFileRequestError as exc:
-            assert exc.status_code == 502
-            assert exc.detail == "Dify API download request response is invalid"
-        else:
-            raise AssertionError("expected AgentStubFileRequestError")
 
     asyncio.run(scenario())
diff --git a/dify-agent/tests/local/dify_agent/agent_stub/server/test_grpc_service.py b/dify-agent/tests/local/dify_agent/agent_stub/server/test_grpc_service.py
index 149ce1cbffe..b179dc70921 100644
--- a/dify-agent/tests/local/dify_agent/agent_stub/server/test_grpc_service.py
+++ b/dify-agent/tests/local/dify_agent/agent_stub/server/test_grpc_service.py
@@ -130,7 +130,7 @@ def test_agent_stub_grpc_transport_delegates_file_download_requests() -> None:
         async def create_download_request(self, *, principal, request):
             assert principal.execution_context.user_id == "user-1"
             assert request.file.reference == _reference("tool-file-1")
-            assert request.for_external is False
+            assert request.for_frontend is False
             return type(
                 "Response",
                 (),
@@ -160,7 +160,7 @@ def test_agent_stub_grpc_transport_delegates_file_download_requests() -> None:
                     transfer_method="tool_file",
                     reference=_reference("tool-file-1"),
                 ),
-                for_external=False,
+                for_frontend=False,
             ),
             metadata=(("authorization", f"Bearer {token}"),),
         )
diff --git a/dify-agent/tests/local/dify_agent/server/test_app.py b/dify-agent/tests/local/dify_agent/server/test_app.py
index 1891623b38d..86c2f95dc63 100644
--- a/dify-agent/tests/local/dify_agent/server/test_app.py
+++ b/dify-agent/tests/local/dify_agent/server/test_app.py
@@ -192,6 +192,7 @@ def test_create_app_creates_scheduler_and_closes_after_shutdown(monkeypatch: pyt
         plugin_daemon_api_key="daemon-secret",
         inner_api_url="http://dify-api",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="http://api:5001",
         local_sandbox_endpoint="http://shellctl",
         local_sandbox_auth_token="shell-secret",
         agent_stub_api_base_url="https://agent.example.com/agent-stub",
@@ -230,7 +231,9 @@ def test_create_app_creates_scheduler_and_closes_after_shutdown(monkeypatch: pyt
         assert execution_context_layer.daemon_api_key == "daemon-secret"
         assert shell_layer.agent_stub_token_factory is not None
         token = shell_layer.agent_stub_token_factory(_execution_context(), session_id="abc12ff")
-        decoded = settings.create_agent_stub_token_codec().decode_token(token)
+        token_codec = settings.create_agent_stub_token_codec()
+        assert token_codec is not None
+        decoded = token_codec.decode_token(token)
         assert decoded.execution_context == _execution_context()
         assert decoded.session_id == "abc12ff"
         knowledge_provider = next(provider for provider in layer_providers if provider.type_id == "dify.knowledge_base")
@@ -318,6 +321,7 @@ def test_create_app_wires_authenticated_agent_stub_file_upload_route(monkeypatch
         server_secret_key=_base64url_secret(b"1" * 32),
         inner_api_url="https://api.example.com",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="https://files.example.com",
     )
     token_codec = settings.create_agent_stub_token_codec()
     assert token_codec is not None
@@ -326,9 +330,9 @@ def test_create_app_wires_authenticated_agent_stub_file_upload_route(monkeypatch
     original_async_client = httpx.AsyncClient
 
     def handler(request: httpx.Request) -> httpx.Response:
-        assert str(request.url) == "https://api.example.com/inner/api/upload/file/request"
+        assert str(request.url) == "https://api.example.com/inner/api/agent/files/upload-request"
         assert request.headers["X-Inner-Api-Key"] == "inner-secret"
-        return httpx.Response(200, json={"data": {"url": "https://files.example.com/upload"}})
+        return httpx.Response(200, json={"upload_uri": "/files/upload/for-plugin?sign=1"})
 
     monkeypatch.setattr(
         "dify_agent.agent_stub.server.agent_stub_files.httpx.AsyncClient",
@@ -343,7 +347,7 @@ def test_create_app_wires_authenticated_agent_stub_file_upload_route(monkeypatch
         )
 
     assert response.status_code == 200
-    assert response.json() == {"upload_url": "https://files.example.com/upload"}
+    assert response.json() == {"upload_url": "https://files.example.com/files/upload/for-plugin?sign=1"}
     assert FakeRunScheduler.created[0].shutdown_called is True
     assert fake_http_client.is_closed is True
     assert fake_redis.closed is True
@@ -357,6 +361,7 @@ def test_create_app_wires_authenticated_agent_stub_drive_manifest_route(monkeypa
         server_secret_key=_base64url_secret(b"1" * 32),
         inner_api_url="https://api.example.com",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="https://files.example.com",
     )
     token_codec = settings.create_agent_stub_token_codec()
     assert token_codec is not None
diff --git a/dify-agent/tests/local/dify_agent/server/test_settings.py b/dify-agent/tests/local/dify_agent/server/test_settings.py
index d4c9af76a8b..f669dc0f226 100644
--- a/dify-agent/tests/local/dify_agent/server/test_settings.py
+++ b/dify-agent/tests/local/dify_agent/server/test_settings.py
@@ -71,11 +71,13 @@ def test_server_settings_defaults_shellctl_auth_token_to_none(
 
 def test_server_settings_reads_agent_stub_settings_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("DIFY_AGENT_STUB_API_BASE_URL", "https://agent.example.com/agent-stub/")
+    monkeypatch.setenv("DIFY_AGENT_SANDBOX_FILES_BASE_URL", "https://dify.example.com/prefix/")
     monkeypatch.setenv("DIFY_AGENT_SERVER_SECRET_KEY", _base64url_secret(secrets.token_bytes(32)))
 
     settings = ServerSettings()
 
     assert settings.agent_stub_api_base_url == "https://agent.example.com/agent-stub"
+    assert settings.sandbox_files_base_url == "https://dify.example.com/prefix"
 
 
 def test_server_settings_normalizes_agent_stub_service_root_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -125,6 +127,23 @@ def test_server_settings_rejects_public_agent_stub_api_base_url_without_secret_k
         _ = ServerSettings(agent_stub_api_base_url="https://agent.example.com/agent-stub")
 
 
+def test_server_settings_requires_sandbox_files_base_url_for_agent_stub_file_operations() -> None:
+    with pytest.raises(ValidationError, match="DIFY_AGENT_SANDBOX_FILES_BASE_URL"):
+        _ = ServerSettings(
+            agent_stub_api_base_url="https://agent.example.com/agent-stub",
+            inner_api_key="inner-secret",
+            server_secret_key=_base64url_secret(secrets.token_bytes(32)),
+        )
+
+
+def test_server_settings_rejects_sandbox_files_base_url_query_or_fragment() -> None:
+    with pytest.raises(ValidationError, match="query string or fragment"):
+        _ = ServerSettings(sandbox_files_base_url="https://dify.example.com?x=1")
+
+    with pytest.raises(ValidationError, match="query string or fragment"):
+        _ = ServerSettings(sandbox_files_base_url="https://dify.example.com#fragment")
+
+
 def test_server_settings_accepts_grpc_agent_stub_api_base_url_and_bind_override() -> None:
     settings = ServerSettings(
         agent_stub_api_base_url="grpc://agent.example.com:9091",
@@ -210,6 +229,7 @@ def test_server_settings_create_agent_stub_file_request_handler_returns_handler_
     settings = ServerSettings(
         inner_api_url="https://api.example.com",
         inner_api_key="inner-secret",
+        sandbox_files_base_url="https://sandbox-files.example.com/dify",
     )
 
     handler = settings.create_agent_stub_file_request_handler()
@@ -217,6 +237,7 @@ def test_server_settings_create_agent_stub_file_request_handler_returns_handler_
     assert isinstance(handler, DifyApiAgentStubFileRequestHandler)
     assert handler.inner_api_url == "https://api.example.com"
     assert handler.inner_api_key == "inner-secret"
+    assert handler.sandbox_files_base_url == "https://sandbox-files.example.com/dify"
 
 
 def test_server_settings_create_agent_stub_drive_request_handler_returns_none_without_full_settings() -> None:
diff --git a/docker/.env.example b/docker/.env.example
index abf69363047..d7ac8555e55 100644
--- a/docker/.env.example
+++ b/docker/.env.example
@@ -283,6 +283,9 @@ DIFY_AGENT_E2B_TEMPLATE=difys-default-team/dify-agent-local-sandbox
 DIFY_AGENT_E2B_ACTIVE_TIMEOUT_SECONDS=3600
 DIFY_AGENT_E2B_SHELLCTL_AUTH_TOKEN=
 DIFY_AGENT_E2B_SHELLCTL_PORT=5004
+# Sandbox-reachable Dify API base for dify-agent CLI /files/* transfers.
+# Remote Sandboxes should use the public Dify ingress; local Compose uses api via agent_ssrf_proxy.
+DIFY_AGENT_SANDBOX_FILES_BASE_URL=http://api:5001
 DIFY_AGENT_STUB_API_BASE_URL=http://agent_backend:5050/agent-stub
 # This is security-sensitive: it derives the JWE encryption key for Agent Stub bearer tokens.
 # Replace this development default in production.
diff --git a/docker/docker-compose-template.yaml b/docker/docker-compose-template.yaml
index 856d9d99787..0c864209cad 100644
--- a/docker/docker-compose-template.yaml
+++ b/docker/docker-compose-template.yaml
@@ -681,6 +681,7 @@ services:
       DIFY_AGENT_E2B_SHELLCTL_PORT: ${DIFY_AGENT_E2B_SHELLCTL_PORT:-5004}
       DIFY_AGENT_SANDBOX_FILE_UPLOAD_MAX_BYTES: ${PLUGIN_MAX_FILE_SIZE:-52428800}
       DIFY_AGENT_STUB_API_BASE_URL: ${DIFY_AGENT_STUB_API_BASE_URL:-http://agent_backend:5050/agent-stub}
+      DIFY_AGENT_SANDBOX_FILES_BASE_URL: ${DIFY_AGENT_SANDBOX_FILES_BASE_URL:-http://api:5001}
       # This is security-sensitive: it derives the JWE encryption key for Agent Stub bearer tokens.
       # Replace this development default in production.
       # Generate one with: python -c 'import secrets; print(secrets.token_urlsafe(32))'
diff --git a/docker/docker-compose.yaml b/docker/docker-compose.yaml
index 475225f3b1f..ef3f92a3ae9 100644
--- a/docker/docker-compose.yaml
+++ b/docker/docker-compose.yaml
@@ -687,6 +687,7 @@ services:
       DIFY_AGENT_E2B_SHELLCTL_PORT: ${DIFY_AGENT_E2B_SHELLCTL_PORT:-5004}
       DIFY_AGENT_SANDBOX_FILE_UPLOAD_MAX_BYTES: ${PLUGIN_MAX_FILE_SIZE:-52428800}
       DIFY_AGENT_STUB_API_BASE_URL: ${DIFY_AGENT_STUB_API_BASE_URL:-http://agent_backend:5050/agent-stub}
+      DIFY_AGENT_SANDBOX_FILES_BASE_URL: ${DIFY_AGENT_SANDBOX_FILES_BASE_URL:-http://api:5001}
       # This is security-sensitive: it derives the JWE encryption key for Agent Stub bearer tokens.
       # Replace this development default in production.
       # Generate one with: python -c 'import secrets; print(secrets.token_urlsafe(32))'
diff --git a/docker/envs/core-services/dify-agent.env.example b/docker/envs/core-services/dify-agent.env.example
index d434ecf5945..aa96908531b 100644
--- a/docker/envs/core-services/dify-agent.env.example
+++ b/docker/envs/core-services/dify-agent.env.example
@@ -35,6 +35,8 @@ DIFY_AGENT_E2B_SHELLCTL_PORT=5004
 # Standalone/direct-container byte limit. Full Docker Compose derives this from
 # PLUGIN_MAX_FILE_SIZE in docker/.env.
 DIFY_AGENT_SANDBOX_FILE_UPLOAD_MAX_BYTES=52428800
+# Sandbox-reachable Dify API base for signed /files/* transfers.
+DIFY_AGENT_SANDBOX_FILES_BASE_URL=http://api:5001
 DIFY_AGENT_STUB_API_BASE_URL=http://agent_backend:5050/agent-stub
 # This is security-sensitive: it derives the JWE encryption key for Agent Stub bearer tokens.
 # Replace this development default in production.
diff --git a/docker/ssrf_proxy/test_ssrf_proxy_config.sh b/docker/ssrf_proxy/test_ssrf_proxy_config.sh
index 0c3aecda0ae..e2e6f435b49 100755
--- a/docker/ssrf_proxy/test_ssrf_proxy_config.sh
+++ b/docker/ssrf_proxy/test_ssrf_proxy_config.sh
@@ -39,6 +39,24 @@ http_code_for() {
   printf '%s\n' "$output" | awk '$1 ~ /^HTTP\// { code = $2 } END { print code }'
 }
 
+http_code_for_post() {
+  local proxy_url="$1"
+  local target_url="$2"
+  local output
+
+  output="$(
+    docker run \
+      --rm \
+      --network "$NETWORK_NAME" \
+      --env "http_proxy=$proxy_url" \
+      --env "https_proxy=$proxy_url" \
+      "$CLIENT_IMAGE" \
+      wget -S -O /dev/null -T 10 --post-data=file-bytes "$target_url" 2>&1 || true
+  )"
+
+  printf '%s\n' "$output" | awk '$1 ~ /^HTTP\// { code = $2 } END { print code }'
+}
+
 direct_http_code_for() {
   local target_url="$1"
   local output
@@ -80,6 +98,19 @@ assert_public_target_allowed() {
   fi
 }
 
+assert_post_target_not_blocked() {
+  local proxy_url="$1"
+  local target_url="$2"
+  local status_code
+
+  status_code="$(http_code_for_post "$proxy_url" "$target_url")"
+  if [[ -z "$status_code" || "$status_code" == "403" ]]; then
+    echo "Expected POST $target_url to pass the proxy ACL, got ${status_code:-no response}."
+    docker logs "$AGENT_PROXY_CONTAINER_NAME" >&2 || true
+    exit 1
+  fi
+}
+
 assert_sandbox_bridge_allowed() {
   local target_url="$1"
   local status_code
@@ -214,6 +245,8 @@ assert_private_target_blocked "$agent_proxy_url" "http://agent_backend:5050/inde
 
 # api /files/* must be allowed.
 assert_public_target_allowed "$agent_proxy_url" "http://api:5001/files/test"
+assert_public_target_allowed "$agent_proxy_url" "http://api:5001/files/test?timestamp=1&nonce=2&sign=3"
+assert_post_target_not_blocked "$agent_proxy_url" "http://api:5001/files/upload/for-plugin?timestamp=1&nonce=2&sign=3"
 
 # api non-/files paths must be blocked.
 assert_private_target_blocked "$agent_proxy_url" "http://api:5001/index.html"