Add conductor validate to CI for Jinja path drift (conductor 8ec298d)

[PolyphonyRequiem]

Summary

conductor v0.1.17 added feat(validate): warn on undeclared agent.output refs (commit 8ec298d). When you run conductor validate my-workflow.yaml, it now flags Jinja expressions like {{ some_agent.output.field }} where some_agent has no declared output: schema or where field doesn't exist in the schema.

This is the highest-ROI, lowest-effort conductor feature to adopt. Polyphony has several known cases of Jinja path drift (referencing fields that shifted shape) that were only caught at runtime.

What to do

Add conductor validate as a CI step in the polyphony GitHub Actions workflow:

- name: Validate conductor workflows
  run: |
    pip install "git+https://github.com/microsoft/conductor.git@main"
    find .polyphony-config/registry/workflows -name "*.yaml" \
      | xargs -I{} conductor validate {}

This will surface Jinja path drift bugs at PR time, not at run time.

Prerequisites

• Workflow files need to live in a discoverable path (they do — .polyphony-config/registry/workflows/)
• Only benefits from schema declarations on agent nodes that have output: declared; undeclared outputs are skipped with a warning

Effort/Risk

~30min to add the CI step. No code changes required. Zero runtime risk.

References

• Conductor commit 8ec298d: feat(validate): warn on undeclared agent.output refs
• Mahler adoption survey 2026-05-28 (decision inbox)
• conductor-mechanics skill: M2 (output schema validation)

/cc Epic #521