[BugenZhao]

Overview

Refresh rust/AGENTS.md, which has not changed since the Rust frontend moved into this repo (#43283), and link it from the root AGENTS.md domain-specific guides.

Claims

• Replace stale guidance: "fine to break API" becomes a compatibility rule scoped to real wire consumers, and "prefer splitting into smaller files" becomes splitting by ownership.
• Add the conventions Rust frontend reviews keep applying: a crate ownership table, design principles (strong types, ownership of fields and checks, lifecycle, rejecting unimplemented behavior), Python frontend parity, parser rules, and which evidence supports which claim.
• Ask PR descriptions to list intentional deviations from the guide or from Python frontend behavior, instead of a generic "followed the guide" statement.
• Keep the existing winnow, thiserror-ext, expect-test, for_test(), nextest, and Unix-only rules as written.

Validation

• pre-commit passes on the commit, including check-agent-files (root 158/200 lines, rust/AGENTS.md 116/300) and markdownlint-cli2.
• Two independent agent reviews checked every concrete claim against the code under rust/. The draft was corrected where it disagreed with intentional code: Noop CLI flags, one tool parser type registered under several names, token-identity markers only where the parser receives decoded tokens, and the scripted in-process mock engine versus the random-token vllm-mock-engine binary.

Details

• Duplicate check: no open PR touches rust/AGENTS.md.
• Generic testing, diff, and benchmark advice already covered by the root AGENTS.md and the pr-checklist skill is left out.
• The root link means agents starting from the repo root read the Rust guide before editing rust/.
• Not done: the editing guide's "Tested?" step, running an agent against each new rule.

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Pull Request Checklist

• I used vLLM's /pr-checklist skill. (Mandatory for agents, optional for humans).

• AI assistance was used during the creation of this PR.

• Design Fit: Minimizes impact on core components, reuses existing functionality, and justifies added complexity.

• Testing and Validation: Validates the change and ensures any added tests are meaningful and reliable, with CI coverage or documented CI resource constraints and validation performed outside CI.

• Code Quality and Style: Keeps code and comments clear and concise, and updates relevant documentation and examples.

• Pull Request Contents: Includes a brief summary and relevant links, supports claims with evidence, explains root causes and implementation trade-offs, and follows the contributing guide.

🤖 Generated with Claude Code

[claude]

Claude Code Review

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[BugenZhao]

/ci run

[github-actions]

✅ Triggered Buildkite CI #96371 for commit f2cb535cf802.

ℹ️ This PR is 50 commits behind upstream main. Merged upstream main into this branch as f2cb535cf802 before starting CI. Pull the branch before pushing more changes.