Extend Workflow Engine

Extending the workflow engine

docs/workflow_development.md is the authoritative guide. Read its "Adding things to the workflow engine" section first (new workflow, media runner, spec test, report kind) — this skill covers the v1-side wiring in workflows/workflow_dispatch.py that the doc only mentions in passing, plus the end-to-end verification people skip.

How the two halves connect

Repo-root run.py is the only user-facing entry point. It does NOT import the engine modules — it bridges through workflows/workflow_dispatch.py:

• can_dispatch_to_engine(model_spec, runtime_config) decides routing (run.py:961). If it returns false for a supported workflow, run.py raises rather than falling back to a legacy path.
• build_engine_commands(...) builds VenvCommands that run run_workflows.py inside the WorkflowVenvType.WORKFLOW_RUN_SCRIPT venv.
• run_workflows.py re-imports v1's workflows.model_spec.MODEL_SPECS via a sys.path insert — the model catalog (workflows/model_specs/prod/*.yaml) is shared, not duplicated.

Recurring failure mode: code works when invoking run_workflows.py directly but is unreachable from run.py because a bridge table or a forwarding helper below was not updated.

v1-side wiring checklist (the part people forget)

All in workflows/workflow_dispatch.py unless noted.

1. Onboarding a model → routing is now by model type, not per-name. If the model's ModelType is already in _ENGINE_ROUTED_MODEL_TYPES (frozenset, checked by is_engine_routed_model), a new model of that type is picked up automatically — just add it to the shared catalog workflows/model_specs/prod/<type>.yaml (or dev/ for --dev-mode). A brand-new model type must be added to _ENGINE_ROUTED_MODEL_TYPES. (LLM/VLM route via the workflow-specific _is_*_run predicates in can_dispatch_to_engine, not the frozenset.)
2. New workflow → register it in the engine's WORKFLOW_REGISTRY (workflow_module/workflows.py), and map its WorkflowType to the engine workflow name in _ENGINE_WORKFLOW_NAMES. If no fitting WorkflowType exists, add one to the enum in workflows/workflow_types.py — otherwise it can never be selected via run.py --workflow.
3. New CLI flag → forwarding is explicit, not pass-through. Add the flag to run.py argparse, then forward it in the relevant _forward_* / _build_*_cmd helper (use _extend_if_set(cmd, "--flag", value)), and give run_workflows.py a matching add_argument. If a v1 flag is deliberately unsupported on the engine path, add it to _warn_on_unsupported_args so users get a warning instead of silent ignoring.
4. Runner needs an extra host venv → define a WorkflowVenvType + VenvConfig in workflows/workflow_venvs.py and map model_type → venv in _ENGINE_EVAL_VENV_BY_MODEL_TYPE. _engine_dependency_venv_types only provisions venvs listed there, and only for _ENGINE_EVAL_WORKFLOWS.

Engine-side registries (quick map)

Details in docs/workflow_development.md; the registries to touch:

• Workflows: WORKFLOW_REGISTRY in workflow_module/workflows.py; optionally ReleaseWorkflow.children and a new MediaTaskType wired in run_media_task.
• Media runners: BENCHMARK_DISPATCH / EVAL_DISPATCH in test_module/dispatch.py, keyed by model_spec.model_type.name. The value is the runner's function name (string); _resolve_runner imports it lazily. Export it from test_module/benchmark_tests/__init__.py (or eval_tests/).
• Spec tests: data-driven via test_module/test_suites/<category>.json; guides in test_module/test_categorization_system/TEST_SUITE_CONFIG_GUIDE.md and TEST_MARKING_SYSTEM.md. New test classes subclass BaseTest from _test_common/base_test.py.
• Report kinds: renderer in report_module/renderers.py (schema rules in tests/report_module/SCHEMA_GUIDE.md); acceptance in report_module/acceptance_criteria.py (_check_<kind> + category list in acceptance_criteria_check).

Verify the wiring end-to-end

Always finish by exercising run.py, not run_workflows.py directly:

python run.py --model <model> --workflow <workflow> --device <device> ...

• The run log must contain Model <name> (model_type=<TYPE>) routes through the workflow engine. (run.py:967) followed by Delegating workflow '<name>' to workflow engine. (workflow_dispatch.py:297). If those are missing, the routing in step 1/2 is not wired.
• For flag changes, confirm the value survives the hop: inspect the engine subprocess command logged during the run, and python run_workflows.py --help for the receiving argparse entry.