The question-classifier default shipped two `classes` with blank names. That
turns a loud preflight refusal into a node that is written, reported as a
success, and silently classifies into two meaningless categories -- and the
fabricated ids `["1", "2"]` pin `declared_branch_handles`, so a semantic
`connect` is dropped while the create survives. That is the failure shape the
registry exists to eliminate.
Draw the line explicitly and apply it to every entry: a default may supply a
field whose empty value is semantically NEUTRAL -- a container, a mode, a config
or auth block -- but never one that carries the node's PURPOSE, where an empty
value produces a node that RUNS and yields nothing. Dropped, with the engine
behaviour each empty value would have produced:
end.outputs End runs OK, so run_finished_without_output is
False -> "All checks passed" on an empty result
answer.answer streams nothing
template-transform.template renders ""
variable-aggregator.variables SUCCEEDED, outputs={} -- triage cause (d)
question-classifier.classes two blank categories + fabricated handle ids
question-classifier.query_variable_selector classifies `query or ""`
knowledge-retrieval.dataset_ids retrieves from no dataset, succeeds empty
The whole `if-else` entry goes too, though nothing is gained or lost by it: its
one case has an empty `conditions` list that graphon combines with `all([])`, so
it always matches -- but `iter_cases()` synthesizes that identical case when
`cases` is absent, so dropping the entry does not cure it. It only stops us
writing a fabricated always-true condition that makes the node look configured.
An empty value that fails LOUDLY is not in that category: there is no silence to
protect against, and dropping it would pay the full batch-refusal cost for
nothing. Verified loud, so these stay -- `llm.model` (never launches, "model not
configured"), `llm.prompt_template` (empty messages are filtered out, leaving
zero, so graphon raises `NoPromptFoundError`), `code.code` (the sandbox runner
calls `main(**inputs_obj)` with no `main` defined), `code.outputs` (graphon
raises `CodeNodeError("Not all output parameters are validated.")` for any key
the code returns), and `http-request.url` (`Executor._init_url` raises
`InvalidURLError("url is required")` before any request goes out).
`template-transform.variables` stays too -- it is structural, and it is the
exact field the live F4 failure was missing.
The placeholder agent genuinely means "no dataset, no output", so it now says
so itself instead of borrowing a default that would say it for every caller.
The engine sweep is re-pinned in both directions: the fields the engine reports
missing from a node built from a default ALONE must be exactly the purpose
fields the registry refuses to fabricate -- no more (a structural regression)
and no fewer (a silent-success regression).
Also: name the `filter_applicable` test after what it actually asserts, since
that function does not return its working graph; and reword the comment in
`graph_normalizers` that quoted a bare `type` marker, one reflow away from
being read as a type comment and silently killing the type check again.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
An Edit LLM writes only the fields it was thinking about. graphon requires a
handful per node type with no default, so `create_node{template-transform,
{title, template}}` produced a node the draft preflight refused -- and the
refusal killed the WHOLE repair batch, parking the session at
`edit.plan_approval` with an identical card on every approval (triage
`edit-branch-failure-2026-09-22` cause (b)).
Extend the node-type default registry to every type the Build/Edit/Fix agents
may create -- template-transform, code, http-request, variable-aggregator,
answer, question-classifier, if-else, tool -- each taken from the matching
`web/app/components/workflow/nodes/<type>/default.ts` and each cited alongside
the graphon field it covers. Add `default_config_or_empty`, a non-raising
lookup: a type the registry does not cover contributes no defaults rather than
aborting the edit that is creating it.
Merge those defaults UNDER the caller's config at `graph_ops._build_node`, the
one construction point every created node passes through. A field the caller
supplied always wins; only a missing one is filled. That covers Build, Edit and
Fix, `create_node` and `insert_between`, and the `filter_applicable` dry run,
so the dry run sees exactly the node the port will write.
Defaults fill MISSING required fields; a field that is present but WRONG stays
`graph_normalizers.heal_nodes_for_preflight`'s job.
Two editor-only keys are deliberately not copied. `_targetBranches` (if-else,
question-classifier) is frontend state the canvas regenerates from
`cases`/`classes`, which is also where `declared_branch_handles` reads handles
from. A caller-supplied `cases`/`classes` wins the merge while a default
`_targetBranches` would not, so shipping it would attach a stale branch list to
every Builder-created branch node.
Move the registry from `services/dify_builder/` to `core/dify_builder/`: it was
imported by `core/dify_builder/placeholder_agent.py`, against the constraint
that `core/` must not import from `services/`. The dependency now points the
legal way, and the module stays pure -- copy, typing and graphon only.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Charles YaoandClaude Opus 5