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Troubleshoot Golang programs systematically - find and fix the root cause. Use when encountering bugs, crashes, deadlocks, races, or unexpected behavior in Go code. Covers debugging methodology, commo
The skill file stays in the publisher's repository.
Paste the copied command in a terminal. It installs this SKILL.md into that agent.
npx skills add samber/cc-skills-golang --skill golang-troubleshooting -a cursor -y
Troubleshoot Golang programs systematically - find and fix the root cause. Use when encountering bugs, crashes, deadlocks, races, or unexpected behavior in Go code. Covers debugging methodology, common Go pitfalls, test-driven debugging, pprof setup and capture, Delve, race detection, GODEBUG tracing, and production debugging. Start here for any 'something is wrong' situation. Not for interpreting profiles or benchmarking (→ See `samber/cc-skills-golang@golang-benchmark` skill), applying optimization patterns (→ See `samber/cc-skills-golang@golang-performance` skill), or designing new code (→ See `samber/cc-skills-golang@golang-safety` skill for defensive coding, `samber/cc-skills-golang@golang-concurrency` skill for concurrency design).
Troubleshoot Golang programs systematically - find and fix the root cause. Use when encountering bugs, crashes, deadlocks, races, or unexpected behavior in Go code. Covers debugging methodology, common Go pitfalls, test-driven debugging, pprof setup and capture, Delve, race detection, GODEBUG tracing, and production debugging. Start here for any 'something is wrong' situation. Not for interpreting profiles or benchmarking (→ See `samber/cc-skills-golang@golang-benchmark` skill), applying optimization patterns (→ See `samber/cc-skills-golang@golang-performance` skill), or designing new code (→ See `samber/cc-skills-golang@golang-safety` skill for defensive coding, `samber/cc-skills-golang@golang-concurrency` skill for concurrency design).
name: golang-troubleshooting
description: "Troubleshoot Golang programs systematically - find and fix the root cause. Use when encountering bugs, crashes, deadlocks, races, or unexpected behavior in Go code. Covers debugging methodology, common Go pitfalls, test-driven debugging, pprof setup and capture, Delve, race detection, GODEBUG tracing, and production debugging. Start here for any 'something is wrong' situation. Not for interpreting profiles or benchmarking (→ See samber/cc-skills-golang@golang-benchmark skill), applying optimization patterns (→ See samber/cc-skills-golang@golang-performance skill), or designing new code (→ See samber/cc-skills-golang@golang-safety skill for defensive coding, samber/cc-skills-golang@golang-concurrency skill for concurrency design)."
user-invocable: true
license: MIT
compatibility: Designed for Claude Code, Codex or similar harness, and for projects using Golang.
metadata:
author: samber
version: "1.3.1"
openclaw:
emoji: "🔍"
homepage: https://github.com/samber/cc-skills-golang
requires:
bins:
- go
- dlv
install:
- kind: go
package: github.com/go-delve/delve/cmd/dlv@latest
bins: [dlv]
allowed-tools: Read Edit Write Glob Grep Bash(go:) Bash(golangci-lint:) Bash(git:) Bash(dlv:) Agent WebFetch WebSearch AskUserQuestion
paths:
Persona: You are a Go systems debugger. You follow evidence, not intuition — instrument, reproduce, and trace root causes systematically.
Thinking mode: Reason as thoroughly as possible for debugging and root cause analysis — rushed reasoning leads to symptom fixes, deep thinking finds the actual root cause. On Claude Code, use ultrathink to trigger extended thinking explicitly.
Orchestration mode: Fan out the five bug-category sub-agents described in Codebase bug hunt mode for a codebase-wide bug hunt. A single-issue debug session should stay sequential; orchestration only pays off when scanning broadly for unknown bugs. On Claude Code, use ultracode to opt into multi-agent orchestration explicitly.
Modes:
Dependencies:
go install github.com/go-delve/delve/cmd/dlv@latestNO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST. Symptom fixes create new bugs and waste time. This process applies ESPECIALLY under time pressure — rushing leads to cascading failures that take longer to resolve.
When the user reports a bug, crash, performance problem, or unexpected behavior in Go code:
fmt.Println, test isolation) and only reach for pprof, Delve, or GODEBUG when simpler tools are insufficient.WHAT ARE YOU SEEING?
"Build won't compile"
→ go build ./... 2>&1, go vet ./...
→ See [compilation.md](./references/compilation.md)
"Wrong output / logic bug"
→ Write a failing test → Check error handling, nil, off-by-one
→ See [common-go-bugs.md](./references/common-go-bugs.md), [testing-debug.md](./references/testing-debug.md)
"Random crashes / panics"
→ GOTRACEBACK=all ./app → go test -race ./...
→ See [common-go-bugs.md](./references/common-go-bugs.md), [diagnostic-tools.md](./references/diagnostic-tools.md)
"Sometimes works, sometimes fails"
→ go test -race ./...
→ See [concurrency-debug.md](./references/concurrency-debug.md), [testing-debug.md](./references/testing-debug.md)
"Program hangs / frozen"
→ curl localhost:6060/debug/pprof/goroutine?debug=2
→ See [concurrency-debug.md](./references/concurrency-debug.md), [pprof.md](./references/pprof.md)
"High CPU usage"
→ pprof CPU profiling
→ See [performance-debug.md](./references/performance-debug.md), [pprof.md](./references/pprof.md)
"Memory growing over time"
→ pprof heap profiling
→ See [performance-debug.md](./references/performance-debug.md), [concurrency-debug.md](./references/concurrency-debug.md)
"Slow / high latency / p99 spikes"
→ CPU + mutex + block profiles
→ See [performance-debug.md](./references/performance-debug.md), [diagnostic-tools.md](./references/diagnostic-tools.md)
"Simple bug, easy to reproduce"
→ Write a test, add fmt.Println / log.Debug
→ See [testing-debug.md](./references/testing-debug.md)
Remember: Read the Error → Reproduce → Measure One Thing → Fix → Verify
Most Go bugs are: missing error checks, nil pointers, forgotten context cancel, unclosed resources, race conditions, or silent error swallowing.
Go error messages are precise. Read them fully before doing anything else:
NEVER debug by guessing — reproduce first. Always:
git bisect to find the breaking commitNever rely on intuition for performance or concurrency bugs:
Change one thing, measure, confirm. If you change three things at once, you learn nothing.
You MUST understand why the bug happens before writing a fix. A band-aid that masks the symptom leaves the defect in place, so it resurfaces elsewhere — usually further from its cause and harder to trace the second time.
When you don't understand the issue:
Before flagging a bug or proposing a fix, trace the data flow and check for upstream handling. A function that looks broken in isolation may be correct in context — callers may validate inputs, middleware may enforce invariants, or the surrounding code may guarantee conditions the function relies on.
samber/cc-skills-golang@golang-gopls skill to resolve the actual symbol through interfaces and embedding — it finds indirect call sites and skips unrelated same-named identifiers that plain grep would respectively miss or falsely match.When the context reduces severity but doesn't eliminate the issue: still report it at reduced priority with a note explaining which upstream guarantees protect it. Add a brief inline comment (e.g., // note: safe because caller validates via parseID() which returns uint) so the reasoning is documented for future reviewers.
Sometimes fmt.Println IS the right tool for local debugging. Escalate tools only when simpler approaches fail. NEVER use fmt.Println for production debugging — use slog.
If any of these are happening, stop and return to Step 1:
General Debugging Methodology — The systematic 10-step process: define symptoms, isolate reproduction, form one hypothesis, test it, verify the root cause, and defend against regressions. Escalation guide: when to escalate from fmt.Println to logging to pprof to Delve, and how to avoid the trap of multiple simultaneous changes.
Common Go Bugs — The bugs that crash Go code: nil pointer dereferences, interface nil gotcha (typed nil ≠ nil), variable shadowing, slice/map/defer/error/context pitfalls, race conditions, JSON unmarshaling surprises, unclosed resources. Each with reproduction patterns and fixes.
Test-Driven Debugging — Why writing a failing test is the first step of debugging. Covers test isolation techniques, table-driven test organization for narrowing failures, useful go test flags (-v, -run, -count=10 for flaky tests), and debugging flaky tests.
Concurrency Debugging — Race conditions, deadlocks, goroutine leaks. When to use the race detector (-race), how to read race detector output, patterns that hide races, detecting leaks with goleak, analyzing stack dumps for deadlock clues.
Performance Troubleshooting — When your code is slow: CPU profiling workflow, memory analysis (heap vs alloc_objects profiles, finding leaks), lock contention (mutex profile), and I/O blocking (goroutine profile). How to read flamegraphs, identify hot functions, and measure improvement with benchmarks.
pprof Reference — Complete pprof manual. How to enable pprof endpoints in production (with auth), profile types (CPU, heap, goroutine, mutex, block, trace), capturing profiles locally and remotely, interactive analysis commands (top, list, web), and interpreting flamegraphs.
Diagnostic Tools — Auxiliary tools for specific symptoms. GODEBUG environment variables (GC tracing, scheduler tracing), Delve debugger for breakpoint debugging, escape analysis ( to find unintended heap allocations), Go's execution tracer for understanding goroutine scheduling.
samber/cc-skills-golang@golang-performance skill for optimization patterns after identifying bottleneckssamber/cc-skills-golang@golang-observability skill for metrics, alerting, and Grafana dashboards for Go runtime monitoringsamber/cc-skills@promql-cli skill for querying Prometheus metrics during production incident investigationsamber/cc-skills-golang@golang-concurrency, samber/cc-skills-golang@golang-safety, samber/cc-skills-golang@golang-error-handling skillsgo build -gcflags="-m"Production Debugging — Debugging live production systems without stopping them. Production checklist, structuring logs for searchability, enabling pprof safely (auth, network isolation), capturing profiles from running services, network debugging (tcpdump, netstat), and HTTP request/response inspection.
Compilation Issues — Build failures: module version conflicts, CGO linking problems, version mismatch between go.mod and installed Go version, platform-specific build tags preventing cross-compilation.
Code Review Red Flags — Patterns to watch during code review that signal potential bugs: unchecked errors, missing nil checks, concurrent map access, goroutines without clear exit, resource leaks from defer in loops.