approval-engine/approval_engine
tegwick 6d0dfc8010 State pdp_digest explicitly; decline to publish a vocabulary mapping
flex-auth asked whether this engine should publish an action/target
mapping between the claim binding's vocabulary (secrets.kv.destroy,
{"id": "lane-openbao-root"}) and a policy package's (destroy, lane:...),
since their package makes no cross-check that a claim was approved for
the action being decided.

Answered no. A PIP asserting that one vocabulary's action means
another's would author policy semantics it does not own, over
vocabularies it does not own, and the failure mode is asymmetric: a wrong
mapping silently accepts a claim approved for a different action, which
is worse than no mapping. binding.pdp_digest is the correspondence and
sidesteps vocabulary entirely -- it compares the PDP's own digest to the
PDP's own digest, with no translation by anyone.

Implemented the part that was ours. pdp_digest was emitted only when
recorded, so a consumer could not distinguish "not issued against a
decision" from "we forgot to look". It is now always present and null in
that case, required-but-nullable in the schema, and documented as
something a PEP on a privileged lane must refuse. This engine states the
fact; enforcing the lane's policy stays with the consumer.

Both published examples were already contradicting the updated schema by
omitting the field -- the same fixture-versus-contract defect flex-auth
hit twice this week and that secrets-engine implemented. Fixed both, made
them cover the PDP-bound and unbound shapes so neither is inferred from
the other, and added tests/test_examples.py to validate every example
against the schema so the class cannot recur here. jsonschema added as a
dev dependency.

94 tests pass (6 new).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TvyJPAaVCGsVheVhcCwNND

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 411227@bnt-lap001
Assistant-Session: d566f6d3-bcaf-43c3-bc5e-3ddd0f64b535
2026-09-06 09:32:11 +02:00
..
__init__.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
api.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
audit.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
auth.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
binding.py Implement the engine spine: claim, outbox, machine, API 2026-08-29 12:52:49 +02:00
cli.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
errors.py Implement approval engine production readiness 2026-09-02 00:52:04 +02:00
pep.py Harden the PEP harness and KeyCape registration request 2026-09-02 15:46:06 +02:00
store.py State pdp_digest explicitly; decline to publish a vocabulary mapping 2026-09-06 09:32:11 +02:00