Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/github/gh-aw/error-messagesnpx skills add github/gh-aw --skill error-messagesgit clone --depth 1 https://github.com/github/gh-awWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00015 | $0.02291 |
| Opus 5 | $0.00008 | $0.01145 |
| Sonnet 5 | $0.00003 | $0.00458 |
| Haiku 4.5 | $0.00002 | $0.00229 |
Grade A, and why
error-messages scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 316 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Error Message Style Guide
Use this format for gh-aw validation errors. Keep messages clear, actionable, and example-driven.
Error Message Template
[what's wrong]. [what's expected]. [example of correct usage]
Make each error message answer three questions:
- What's wrong? - Clearly state the validation error
- What's expected? - Explain the valid format or values
- How to fix it? - Provide a concrete example of correct usage
Constructive Language
Avoid standalone negative wording. Pair it with expected behavior and a concrete fix.
| Avoid only-negative wording | Prefer constructive wording |
|---|---|
invalid |
expected + valid format/options |
cannot |
requires + precondition |
must |
should + example |
failed |
action context + recovery step |
❌ invalid repo format: %s
✅ invalid repo format '%s' — expected 'owner/repo' format (for example: 'github/gh-aw')
❌ not in a git repository
✅ not in a git repository — run 'git init' or 'cd' to a git repository
When to use NewValidationError vs fmt.Errorf
- Use
NewValidationError(field, value, reason, suggestion)in*_validation.gologic.- Use
fieldfor the exact config path - Use
reasonfor what failed - Use
suggestionfor an actionable fix with an example
- Use
- Use
fmt.Errorffor operational/wrapping errors (%w) where you are propagating a lower-level failure with context. - Avoid generic wrappers like
fmt.Errorf("failed to X: %w", err)unless you add recovery guidance.
Suggestion Text Checklist
Every suggestion should:
- Explain what to change
- Include a minimal valid YAML/code example
- Use ✓/✗ markers when ambiguity is likely
Example:
Use one supported engine.
✓ Example:
engine: copilot
✗ Avoid:
engine: unknown
YAML Example Guidelines
- Keep examples minimal and valid YAML
- Use real frontmatter field names
- Quote only when YAML requires it
- Prefer 2-space indentation
Good Examples
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 316 lines · 15 tokens per session scan A eb7cac3b9197
error-messages is a skill published in the GitHub repository github/gh-aw (5,050 stars, last pushed yesterday), licensed MIT. It adds 15 tokens to every session and 2,291 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
c-github
Interact with GitHub using the gh CLI and jq. Manage PRs, issues, repositories, and Actions workflows. Make raw API calls with gh api for anything not covered by built-in commands.
watch-pr
Watch a GitHub pull request for CI status, reviews, comments, merge conflicts, and terminal states using the gh-watch extension. Use when the user wants to monitor a PR, wait for CI, or track PR progress.
watch-tag
Watch a GitHub repository for new tags using the gh-watch extension. Use when the user wants to be notified when a tag is created, when a release is cut, or when a tag that includes a specific commit appears (e.g. "tell me when my merge ships in a release").
watch-branch
Watch a GitHub branch for new commits using the gh-watch extension. Use when the user wants to be notified when new commits are pushed to a branch, monitor main for merges, or track branch activity.
watch-commit
Watch a GitHub commit for CI status changes using the gh-watch extension. Use when the user wants to monitor a commit's CI checks, wait for a build to finish, or track CI progress on a specific SHA.
update-architecture-docs
Generate or update the architecture documentation in docs/content/architecture/. Use on "update architecture docs", "generate architecture documentation", "regenerate architecture docs", or after any structural change to the codebase.