name: go-code-review
description: Perform a senior Go code review on a diff or files, focusing on correctness, idiomatic Go, error handling, maintainability, and performance. Use when the user asks for review, refactor feedback, or PR comments for Go services.
compatibility: Works with diffs or local repo access. Best with gofmt/go test available.
metadata:
short-description: Senior Go PR review
allowed-tools: Bash(git:) Bash(go:) Read

Go Code Review

Review principles

• Correctness > clarity > performance
• Prefer small, explicit abstractions
• Avoid hidden coupling across packages
• Ensure errors are actionable and wrapped

Checklist (prioritized)

Correctness & API behavior

• Context propagation, cancellation, timeouts
• Input validation and boundary conditions
• Error semantics (sentinel vs typed vs wrapped)
• Idempotency for write endpoints if relevant

Concurrency & resources

• Goroutine lifecycle: no leaks; bounded fan-out
• Channels: ownership, close discipline, backpressure
• Locks: avoid contention; avoid deadlocks
• Use errgroup where appropriate

Go idioms & style

• gofmt, naming, package structure
• Avoid needless pointers; avoid interface{} when generics / concrete types suffice
• Minimize exported surface

Performance

• Avoid per-request allocations in hot paths
• Preallocate slices/maps when size known
• Avoid converting between []byte/string unnecessarily
• DB queries: N+1, missing indexes, scanning errors

Observability & ops

• Structured logs; include request ids
• Metrics for errors/latency where important
• Trace propagation (if applicable)

Workflow

1. Determine input: diff, files, or PR context.
2. Produce review comments grouped by severity:
3. Blockers
4. Important
5. Nit / style
6. For each comment:
7. Quote the relevant code snippet (short)
8. Explain impact
9. Provide a concrete fix suggestion

Output format

• Use bullet points, grouped by severity.
• Include small patch suggestions when helpful.