fix(manifest): point root plugin.json at Agent Plugins v1.0.0

[tmchow]

Summary

Root plugin.json used Antigravity’s $schema URL, so a conformant Agent Plugins client must reject the whole package at the door. This PR points that manifest at the Agent Plugins v1.0.0 schema, mirrors public metadata, locks the authoring rules in CI, and records internal posture docs.

Beyond the original plan-only branch, this includes the implementation of U1–U3 (manifest + guard + specs), not just the plan document.

What changed

• plugin.json: $schema → https://agent-plugins.org/schemas/1.0.0/plugin.schema.json; author/homepage/repository/license/keywords mirrored from .claude-plugin/plugin.json; version left for release-please.
• CI: Agent Plugins authoring assertions in tests/release-metadata.test.ts (schema const, name pattern, closed field set, author/value/extensions shapes + negative fixtures).
• Docs: docs/specs/agent-plugins.md (posture + skills-ref vs runtime nuance for Claude frontmatter); small docs/specs/antigravity.md note; plan under docs/plans/.

No skill frontmatter edits. No README marketing note. No converter target in this PR.

Skills frontmatter (explicit non-blocker)

Claude-only top-level keys (argument-hint, disable-model-invocation) fail the reference skills-ref validator. That does not prove shipping Agent Plugins clients skip those skills—many clients ignore unknown fields. Runtime impact is unverified; optional converter remains follow-up only if a client requires reference-clean emission.

Validation

• bun test tests/release-metadata.test.ts (includes new guard suite)
• bun run release:validate
• agy plugin validate . and agy plugin validate ./.agy (v1.0.10)
• grok plugin validate .

Related

• Fixes fix(manifest): conform root plugin.json to Agent Plugins v1.0.0 #1341
• Related: docs(plans): add Agent Plugins v1.0.0 manifest conformance plan #1342 (earlier plan-only draft on cursor/agent-plugins-conformance-plan-c1d8)

Security Disclosure

No security-relevant changes. Manifest metadata and test-only assertions only; no shell/exec, secrets, or permission surface changes.

Agent Disclosure

• Model: Grok Build · Grok 4.5

[Shakeyswings]

LGTM — Approve.

This PR updates the root plugin.json to point at the Agent Plugins v1.0.0 schema, mirrors public metadata, adds CI authoring assertions, and records posture docs. Changes are limited to metadata, tests, and docs (no runtime/permission changes). I reviewed the diffs and the new guard tests; they address the conformance gap described in the PR.

Please convert this draft to a ready PR and wait for CI to finish; otherwise, this is approved and can be merged once CI is green.

[Shakeyswings]

LGTM — Approve.

This PR updates the root plugin.json to point at the Agent Plugins v1.0.0 schema, mirrors public metadata, adds CI authoring assertions, and records posture docs. Changes are limited to metadata, tests, and docs (no runtime/permission changes). I reviewed the diffs and the new guard tests; they address the conformance gap described in the PR.

Please convert this draft to a ready PR and wait for CI to finish; otherwise, this is approved and can be merged once CI is green.

[tmchow]

LGTM — Approve.

This PR updates the root plugin.json to point at the Agent Plugins v1.0.0 schema, mirrors public metadata, adds CI authoring assertions, and records posture docs. Changes are limited to metadata, tests, and docs (no runtime/permission changes). I reviewed the diffs and the new guard tests; they address the conformance gap described in the PR.

Please convert this draft to a ready PR and wait for CI to finish; otherwise, this is approved and can be merged once CI is green.

Thanks for reviewing it. Just fyi you don't need to spend your tokens on automated reviews, we've got it covered :)

Also can you ensure your bot isn't double posting comments? Thanks!