managing-go-modules

name	managing-go-modules
description	Use when working with Go Modules — go modules package management. Covers module initialization, dependency resolution, version management, module proxying, vendoring, and vulnerability scanning. Use when managing Go modules, resolving dependency conflicts, analyzing module graphs, or auditing module vulnerabilities.
connection_type	go-modules
preload	false

Go Modules Management Skill

Manage and analyze Go module dependencies, versions, and vulnerability scanning.

MANDATORY: Discovery-First Pattern

Always check current go.mod configuration before modifying dependencies.

Phase 1: Discovery

#!/bin/bash

echo "=== Module Info ==="
head -5 go.mod 2>/dev/null

echo ""
echo "=== Go Version ==="
go version 2>/dev/null

echo ""
echo "=== Direct Dependencies ==="
grep -v '// indirect' go.mod 2>/dev/null | grep -E '^\t' | head -15

echo ""
echo "=== Go Environment ==="
go env GOPATH GOMODCACHE GOPROXY GONOSUMCHECK 2>/dev/null

Phase 2: Analysis

#!/bin/bash

echo "=== Module Graph Summary ==="
go mod graph 2>/dev/null | wc -l | xargs -I{} echo "Total dependency edges: {}"

echo ""
echo "=== Outdated Modules ==="
go list -u -m all 2>/dev/null | grep '\[' | head -15

echo ""
echo "=== Vulnerability Scan ==="
go install golang.org/x/vuln/cmd/govulncheck@latest 2>/dev/null
govulncheck ./... 2>/dev/null | head -20

Output Rules

• TOKEN EFFICIENCY: Target <=50 lines per output
• List direct vs indirect dependencies separately
• Report vulnerability findings concisely
• Show module graph density, not full graph

Common Operations

Module Tidying

#!/bin/bash
echo "=== Tidy Check ==="
cp go.mod go.mod.bak
go mod tidy 2>&1
diff go.mod.bak go.mod 2>/dev/null | head -15
rm go.mod.bak 2>/dev/null

Module Lookup

#!/bin/bash
MODULE="${1:?Module path required}"
echo "=== Module Info: $MODULE ==="
go list -m -json "$MODULE@latest" 2>/dev/null | jq '{
  Path: .Path,
  Version: .Version,
  Time: .Time
}' 2>/dev/null

echo ""
echo "=== Available Versions ==="
go list -m -versions "$MODULE" 2>/dev/null

Safety Rules

• Run go mod tidy after adding or removing dependencies
• Review go.sum changes before committing -- unexpected changes may indicate supply chain issues
• Use govulncheck before releases to scan for known vulnerabilities
• Vendor dependencies for critical production services with go mod vendor

Output Format

Present results as a structured report:

Managing Go Modules Report
══════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative