Link Validation Skill

Validates markdown links in your workspace using lychee.

Self-Evolving Skill: This skill improves through use. If instructions are wrong, parameters drifted, or a workaround was needed — fix this file immediately, don't defer. Only update for real, reproducible issues.

When to Use This Skill

Use this skill when:

• Checking for broken links in markdown files
• Validating link paths before committing documentation
• Proving a doc change left no dangling internal link

How to Run It

The working path is the offline lychee check in tasks/link-check.sh. Inside the cc-skills repository it is part of the quality gate:

moon run repo:link-check     # this check alone
moon run repo:check          # the whole gate, link-check included
bash tasks/link-check.sh     # the same script without moon

In any other workspace, run the same lychee command from the repository root:

lychee --offline --no-progress --root-dir "$(git rev-parse --show-toplevel)" './**/*.md'

Add --config lychee.toml when the repository has one; lychee also loads ./lychee.toml by itself.

What the Check Does

tasks/link-check.sh:

1. cds to the working-tree root (git rev-parse --show-toplevel, so it is correct inside a worktree too)
2. Runs bunx lychee --config lychee.toml --offline --no-progress --root-dir <repo root> './**/*.md'
3. Excludes plugins/statusline-tools/tests/fixtures, whose links are broken on purpose
4. Prints lychee's summary line, then ✓ every internal link resolves or ✗ broken internal links found (lychee exit N), and exits with lychee's exit code

It checks relative links, root-relative links (/docs/adr/x.md, resolved through --root-dir) and #anchor fragments. It is offline by design: external URL liveness depends on the network and on other sites' uptime, so it is not checked. Nothing is written to disk except lychee's own .lycheecache; the result is the terminal output and the exit code.

A path that exists on one machine only (~/..., another repository) cannot pass. Write it as inline code instead of a link.

Requirements

• lychee: tasks/link-check.sh runs it through bunx, so Bun is enough there; elsewhere install it (brew install lychee)

Configuration

cc-skills keeps one lychee config, lychee.toml at the repository root. It holds the path and URL exclusions and include_fragments = "anchor-only" (lychee 0.24 rejects the old boolean true). The statusline-tools Stop hook reads the same file when it exists.

Related Checks

• Link portability in skills (absolute repo paths that break once installed): the link-validator skill
• Path policy at session end: the statusline-tools Stop hook runs lint-relative-paths and lychee, and writes .lychee-results.json for the status line

History

This skill used to describe a Stop hook, hooks/stop-link-check.py, that wrote .link-check-results.md. link-tools never had a hooks.json, so the hook never ran; it was deleted in issue #33.

References

• ADR: Link Checker Plugin Extraction
• lychee Documentation

Troubleshooting

Post-Execution Reflection

After this skill completes, check before closing:

1. Did the command succeed? — If not, fix the instruction or error table that caused the failure.
2. Did parameters or output change? — If the underlying tool's interface drifted, update Usage examples and Parameters table to match.
3. Was a workaround needed? — If you had to improvise (different flags, extra steps), update this SKILL.md so the next invocation doesn't need the same workaround.

Only update if the issue is real and reproducible — not speculative.