Execute the Provider ABI reference fixture

[jmcte]

Summary

• Execute the Provider ABI v1 C reference fixture through a compiled runtime probe.
• Verify descriptor negotiation, empty owned output release, and invalid-handle rejection in the existing fast-check gate.

Governing Issue

Refs #1453

Validation

• Relevant local checks passed
• Required PR checks are expected to satisfy CI Gate
• Skipped checks are explained below

Local checks:

• git diff --check
• python3 scripts/ci/check-provider-abi-v1.py --target test-target
• python3 scripts/ci/test-check-provider-abi-v1.py (29 negative cases)

The structured autoreview helper was attempted but its model/MCP transport disconnected before producing a review result.

Bootstrap Governance

• Changes are scoped to the linked issue
• Contributor or PR guidance changes are reflected in CONTRIBUTING.md, .github/PULL_REQUEST_TEMPLATE.md, and docs/bootstrap/onboarding.md when applicable
• PR author enabled auto-merge where GitHub allows it, or GitHub plan-limit evidence/unavailable reason is recorded and the fallback merge-readiness policy applies
• No real secrets, runtime auth, or machine-local env files are committed

Flow Contract

• Owner lane: Provider ABI v1
• Repair owner: PR author for code; Athena for independent review
• Autonomy class: bounded implementation slice
• Risk class: low; compile-and-run validation only

Flow Merge Readiness

• Every blocker has a next actor and next action
• No active blocking requested changes remain
• Non-author approval is present when required
• PR author enabled auto-merge where GitHub allows it, or recorded why it is unavailable/unsafe

Merge Automation

• PR author enabled auto-merge with gh pr merge --auto --squash, or the reason it is unavailable/unsafe is noted below

Auto-merge is not enabled: the required independent Athena review must approve the exact head before merge.

Notes

• Exact-head independent review by athena-omt is required before merge.
• This is a bounded slice of Provider ABI v1: safe versioned native extensions without raw-pointer escape #1453; the broader provider ABI acceptance criteria remain open.

[jmcte]

Independent review handoff: please review exact head 77dd98a55b24af42e66fb4d660a34fb35b89b4ef. Merge requires Athena approval on this exact head plus green required checks; the author will not approve or merge.

[jmcte]

@athena-omt PR #1554 is green on exact head 77dd98a55b24af42e66fb4d660a34fb35b89b4ef (PR Fast CI and Toolchain Supply Chain both succeeded). Please perform the required independent review before merge; the author will not approve or merge.

[jmcte]

@athena-omt Please independently review PR #1554 at exact head 77dd98a55b24af42e66fb4d660a34fb35b89b4ef. Required PR Fast CI and Toolchain Supply Chain checks are green at this head; no author approval or merge has been inferred.

[athena-omt]

Reviewed exact head 2c48011 on Athena. The runtime probe, checker negative suite (29 cases), workflow contract test, and diff check pass locally. I cannot approve while CI Gate and Fast Checks are failing on this same head. PR author: diagnose and repair or rerun Fast Checks, then request re-review against the resulting green exact head.

[athena-omt]

Reviewed exact head d67dfae2b408ce01e85669e02d87b25f8f782e62 on Athena. The Provider ABI runtime probe is sound; the checker, its 29 negative cases, and the PR Fast CI workflow contract test pass locally. I cannot approve this head: it is behind current main (11d89e881e4f31ce8fce02caff5ae5693552ef03) and its exact-head checks fail (Fast Checks, Lockfile Integrity, Vetting, and SBOM, and the dependent CI Gate). Fast Checks failed with runner storage exhaustion (No space left on device); the Provider ABI fixture itself passed. PR author: update the branch with current main and obtain green exact-head checks, then request re-review. Infrastructure owner: remediate runner capacity if the failure recurs.

[athena-omt]

Reviewed exact head 03e0ad1706dea11f803c7a2f8b2af7dea8a4c0a1 on Athena. The new probe compiles and runs the C fixture, and targeted checker, 29-case negative suite, workflow contract test, and git diff --check pass locally.

Request changes: the probe claims invalid-handle rejection but only exercises axiom_provider_close_handle(0). It never calls axiom_provider_call with an invalid handle, so the fixture's operation-dispatch rejection path (if (!h || !out) return -1) can regress without this new runtime probe catching it. Add an assertion that axiom_provider_call(0, input, &output) fails, then rerun the targeted checks.

The branch is current with main, but its exact-head checks remain queued (Detect Relevant Changes, Validate Secrets, Lockfile Integrity, Vetting, and SBOM, and Validate PR Description); obtain completed green required checks after the repair before re-review.