fix(ai-openrouter): keep root metadata out of requests

[slegarraga]

🎯 Changes

Fixes #735.

• Stops forwarding root chat() metadata into OpenRouter chat-completions request metadata.
• Keeps provider-native OpenRouter request metadata available through modelOptions.metadata.
• Adds unit and E2E regression coverage for structured root observability metadata.

Test plan

• corepack pnpm run build:all
• corepack pnpm --filter @tanstack/ai-openrouter test:lib
• corepack pnpm --filter @tanstack/ai-openrouter test:types
• corepack pnpm --filter @tanstack/ai-openrouter test:eslint
• corepack pnpm --filter @tanstack/ai-e2e exec playwright test tests/chat.spec.ts -g "openrouter root metadata"
• corepack pnpm --filter @tanstack/ai-e2e build

Full pnpm run test:pr was not run locally.

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested this code locally with pnpm run test:pr.

🚀 Release Impact

• This change affects published code, and I have generated a changeset.
• This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

• Bug Fixes

  • Root chat metadata is now retained as observability context instead of being forwarded into the OpenRouter API request, improving metadata isolation.

• New Features

  • Added support for structured root metadata in observability tracking for OpenRouter chat flows.

• Tests

  • Added end-to-end tests to verify root metadata handling behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: e107f92d-12b7-43f7-b7aa-6ad3a114f0a6

📥 Commits

Reviewing files that changed from the base of the PR and between 984ac3c and 57cedc0.

📒 Files selected for processing (6)

• .changeset/openrouter-root-metadata.md
• packages/ai-openrouter/src/adapters/text.ts
• packages/ai-openrouter/tests/openrouter-adapter.test.ts
• testing/e2e/src/routes/$provider/$feature.tsx
• testing/e2e/src/routes/api.chat.ts
• testing/e2e/tests/chat.spec.ts

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📝 Walkthrough

Walkthrough

This PR fixes a regression where OpenRouter's text adapter was forwarding root-level observability metadata to the wire request, causing validation failures on structured metadata. The fix removes the root metadata from the request body, restricts observability metadata to middleware/devtools consumers, and enables structured e2e tests to verify the corrected behavior.

Changes

OpenRouter root metadata observability fix

Layer / File(s)	Summary
Adapter fix and unit test updates packages/ai-openrouter/src/adapters/text.ts, packages/ai-openrouter/tests/openrouter-adapter.test.ts, .changeset/openrouter-root-metadata.md	mapOptionsToRequest no longer spreads options.metadata into the request body. Unit tests confirm root metadata is excluded from the SDK request while modelOptions.metadata is forwarded and validated through the Zod outbound schema. Changeset documents the patch release.
E2E test infrastructure setup testing/e2e/src/routes/$provider/$feature.tsx, testing/e2e/src/routes/api.chat.ts	Route search validation parses a rootMetadata parameter, chat feature destructures and forwards it via useChat, and the API route constructs a structured observability metadata object and injects it into chat() calls across structured-output branches.
E2E test execution testing/e2e/tests/chat.spec.ts	New Playwright test for OpenRouter verifies that structured root metadata flows correctly without validation errors.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Suggested reviewers

• KevinVandy
• tombeckenham

Poem

🐰 Metadata once climbed the wire in haste,
Failing Zod's Record<string, string> taste,
Now it stays home, where middleware may peek,
While modelOptions.metadata flows sleek—
Root observability finds its place! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(ai-openrouter): keep root metadata out of requests' directly and clearly describes the main change: preventing root-level metadata from being forwarded into OpenRouter requests.
Linked Issues check	✅ Passed	The PR successfully addresses issue #735 by removing root metadata forwarding, preserving modelOptions.metadata, and adding comprehensive unit and e2e tests for structured root observability metadata.
Out of Scope Changes check	✅ Passed	All changes are directly related to the stated objective: the adapter fix, changeset documentation, unit tests, and e2e test infrastructure changes are all within scope of fixing the metadata forwarding issue.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

Tools execution failed with the following error:

Failed to run tools: 14 UNAVAILABLE: read ECONNRESET

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