[Pllutonyy]

Summary

• Preserve both request-scoped tool metadata maps before stripping their transport side channels.
• Responses pivots carry object-valued namespace identities plus string-valued provider aliases. The previous extraction preferred the namespace map and deleted the alias map; its recovery fallback could not recover strings from namespace objects.
• Add extractRequestToolMetadata and use its captured alias ledger in chatCore, while retaining later provider-specific map precedence and legacy extraction behavior for other callers.
• No sanitizer changes, guessed name mappings, auth changes, new provider or runtime feature flag.

Related Issues

• Related-issue state UNVERIFIED at submission: recheck live fix(providers): Antigravity tool names break Claude Code — hashed MCP ids emitted by our own sanitizer #12007 and fix(providers): Responses namespace identity map is dropped by the hub-and-spoke pivot #9780/fix(translator): keep Responses namespace identity across the hub-and-spoke pivot #9783 and link the correct issues. Earlier notes conflict on whether fix(providers): Antigravity tool names break Claude Code — hashed MCP ids emitted by our own sanitizer #12007 is closed or open.
• Base-red inherited: 🔴 Release branch not green: release/v3.8.51 #12732.

Validation

• Change type: routing / provider translation
• Red-before-green: four new namespace/alias cases reproduced the loss before the fix; the namespace-only guard already passed.
• Focused five-file suite: 30 passed; one additional parallel-MCP regression subsequently passed (31 distinct checks across those runs).
• Scoped ESLint on both production files and the new test file.
• Changed metadata helper coverage: 100% lines, branches and functions in the focused coverage run.
• Live Responses SSE namespace/collision identity and tool-result continuation.
• Native Codex CLI 0.153.3: real Graft freshness and OpenViking health calls completed, final exact marker returned, exit 0.
• Full lint/CI/coverage matrix and production packaging.
• Production changes include a regression test.
• npm run typecheck:core: clean.
• check:provider-consistency and check:provider-assets: pass.
• git diff --check: clean.

Tests Added Or Updated

• tests/unit/antigravity-responses-tool-metadata-roundtrip.test.ts exercises real request and response translators, the chatCore metadata-extraction helper, exact namespace/name restoration on added/done/completed events, genuine sanitizer collisions, four-turn replay without hash growth, alias-only and namespace-only requests, and parallel native MCP calls following reasoning.

Coverage Notes

• The changed open-sse/handlers/chatCore/requestToolIdentity.ts reached 100% line/branch/function coverage. Live HTTP and native-client tests cover the new chatCore wiring; they do not replace the full cross-platform build/CI matrix.

Reviewer Notes

• The live tests ran the isolated worktree's actual Next HTTP server in full profile on loopback, not a modified production deployment.
• Model: antigravity/gemini-3.1-pro-low, explicitly present in the account's synced catalog. This is evidence for that route, not every Antigravity model or multi-account behavior.
• Cleanup: temporary credentials inactive/cleared, child processes exited, test listeners closed. The running full build remains at 2265ce761f76b6c81e34515cc8483ca127d4b414.
• This does not establish Claude Code continuation, multi-account/long-session parity or release readiness. Nothing was promoted.

[diegosouzapw]

This looks like the safer, more conservative half of the namespace/alias overlap with
#12928 — capturing both the alias ledger and the namespace-identity ledger before either
side channel is stripped, without introducing any name-guessing heuristics. The new
roundtrip test is thorough and exercises real translator code. Two asks before merge: add a
changelog fragment, and let's confirm merge order against #12928 (which touches a
different part of the same file) so the two don't fight each other. Queuing for a final
test run.