[Bug]: spec/schema JSON (cedar_advice, manifest) is not shipped in the agent-control-specification wheel, so hosts copy the advice contract by hand and drift #4043

Package

policy-engine

Description

policy-engine/spec/schema/cedar_advice.schema.json and manifest.schema.json are not part of the installed package. policy-engine/sdk/python/pyproject.toml (maturin, python-source = ".") has no include for them, and the 0.3.1b1 wheel on PyPI contains no .json at all:

$ unzip -l agent_control_specification-0.3.1b1-cp311-abi3-manylinux_2_28_x86_64.whl | grep -c '\.json'
0

The sdist carries core/schema/manifest.schema.json but not cedar_advice.schema.json. Neither Python binding exposes translate_advice or advice validation through _native (only parse_manifest, validate_manifest, validate_manifest_overlay, validate_manifest_artifact, validate_artifacts).

A host that writes its own Cedar dispatcher (a type: custom policy) has to reproduce the advice rules from the JSON schema by hand, and there is nothing installed to check against. The contract has already moved under such a copy: the transform root in cedar_advice.schema.json changed from $policy_target to $target in #3939, and manifest.schema.json dropped bundle_url.

Proposed fix

Two shapes, and I would rather ask than guess:

1. Ship policy-engine/spec/schema/*.json in the wheel (maturin include, or copy them into the package directory at build time) and expose them via importlib.resources.
2. Expose native advice validation / translate_advice through _native, so hosts call the engine's own implementation instead of a copy.

Since the engine now comes from the agent-control-spec crate, the schema may belong there instead; happy to move this request if so. I can send a PR once a shape is chosen.

How does this impact your work?

My dispatcher's advice validation is a hand port of the schema, pinned to a commit hash with a drift check that points at a path that no longer exists on main (core/src/cedar.rs moved to the external agent-control-spec crate).

Timeline

Not blocking.

Steps to Reproduce

1. pip install agent-control-specification==0.3.1b1 (or build main).
2. python -c "import importlib.resources as r, agent_control_specification as m; print([p.name for p in r.files(m).iterdir() if p.name.endswith('.json')])" prints [].
3. Try to validate an advice payload against the shipped contract: nothing installed provides it.

Environment

agent-control-specification 0.3.1b1 (PyPI) and main e7f5d2b, Python 3.12, macOS.

Logs / Error Output

Not applicable.

Code of Conduct

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