Rust Simplify

Use this skill for bounded Rust cleanup work in the Citum workspace when the task is to improve code quality rather than fix a specific bug.

When .jj is present, use docs/guides/JJ_AI_CHANGE_STACK.md for optional local change isolation and intent capture before publishing through Git/GitHub.

Read first:

• docs/guides/CODING_STANDARDS.md
• docs/guides/AGENT_SKILLS.md

Target Selection

• Prefer jcodemunch symbol and file analysis before reading large files.
• Pick the highest-value Rust file in the affected crate or module.
• If a file path was supplied, confirm it is actually wired into the build.

Quality Pass

• Reduce duplication and nested control flow.
• Prefer idiomatic Rust and explicit error handling.
• Review suspicious string ownership patterns. Prefer borrowed &str for lookup and comparison work, and allocate String values at real ownership boundaries.
• Do not perform broad allocation churn in hot paths without benchmark evidence.
• Add or update tests when behavior changes.
• When tests change, keep expected values independent of current implementation output and confirm behavior changes would have failed before the fix when practical.
• Keep the scope to one focused file or one tightly related cluster.

Verification

• Run the repo-required Rust checks for any .rs, Cargo.toml, or Cargo.lock change.
• Run python3 scripts/audit-rust-review-smells.py --changed for Rust cleanup passes and review the advisory findings.
• Regenerate schemas if the touched files require it.
• Report the exact checks you ran and the result.

Self-Improvement

When you hit a recurring Rust smell not already caught by the audit script:

1. If it can be expressed as a regex rule, add it to scripts/audit-rust-review-smells.py as a new Rule entry in the RULES tuple — the script is the canonical home for automatable patterns.
2. If it's too contextual for a regex, add a short bullet to the Quality Pass section above instead.

For verification failure modes or jcodemunch quirks, add a bullet to the Verification section above. Include any file updates in the same commit. One concrete rule per observation — keep the scope tight.