A documentation link checker that scans Markdown and similar files for links that no longer work, missing page anchors, and optionally invalid external web addresses.

Use it to check a documentation folder, validate internal links and anchors, and optionally test external URLs. It reports problems and can suggest fixes.

It catches broken references before documentation is published or during routine maintenance. This prevents readers from reaching missing pages or sections.

check-links — Skill for Claude Code by ekline-io

Install

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.

Any agent

npx skills add ekline-io/ekline-docs-skills --skill check-links

Clone the repo

git clone --depth 1 https://github.com/ekline-io/ekline-docs-skills

Made for: Claude Code.

Or install ekline-docs-skills, the plugin that ships this one along with the rest of its 6 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ekline-io/ekline-docs-skills/check-links/github.svg)](https://agentmods.dev/skills/ekline-io/ekline-docs-skills/check-links)

Your own site

<a href="https://agentmods.dev/skills/ekline-io/ekline-docs-skills/check-links"><img src="https://agentmods.dev/badge/skills/ekline-io/ekline-docs-skills/check-links/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ekline-io/ekline-docs-skills/check-links"><img src="https://agentmods.dev/badge/skills/ekline-io/ekline-docs-skills/check-links.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 716 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What 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 5.1	$0.00050	$0.00716
Opus 5	$0.00025	$0.00358
Sonnet 5	$0.00010	$0.00143
Haiku 4.5	$0.00005	$0.00072

Measured 11d ago against content hash ff6c267fda08, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

check-links 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 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/extract_links.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/check-links/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Check documentation links

Run the helper script to find broken links, then present results and offer fixes.

Inputs

$ARGUMENTS — optional docs directory (defaults to current directory) and optional --external flag to validate external URLs

Steps

1. Run the helper script

python scripts/extract_links.py $ARGUMENTS

If the user included --external, pass it through. Capture the JSON output.

The script handles file discovery, link extraction (Markdown, reference-style, HTML), internal link validation, anchor checking, and optional external URL checking.

Max 200 files per run. External checks limited to 50 URLs.

2. Handle errors

If the JSON contains an error field:

not_a_directory — tell user the specified path is not a valid directory
no_docs_found — tell user no .md/.mdx files were found, suggest a different path

Stop here on error.

3. Present the link report

Show a summary from the summary object:

Files scanned (files_scanned)
Total links found, broken down: internal, anchors, images, external
If files_truncated is true, note that the file limit was reached

Then group broken links by type:

Broken internal links (broken_internal array):

Show file path and line number
Show the link text and target
Show the reason (e.g., "Target file does not exist", "Anchor not found")
If suggestions are available, show them as recommended replacements
If available_anchors are listed, show the valid anchors for the target file

Broken external links (broken_external array):

Show file path, line number, and target URL
Show HTTP status code and reason

Redirects (redirects array):

Show file path, line number, target URL, and HTTP status code
Suggest updating the URL to the redirect target

Orphaned pages (orphaned_pages array):

List doc files not linked from any other doc (excluding README.md and index files)
These may be unreachable from navigation

4. Offer fixes for broken internal links

Read the full file on GitHub · 101 lines

Files

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.

scripts/extract_links.py 16 KB runs code

Changes

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.

11d ago First seen · 101 lines · 50 tokens per session scan A ff6c267fda08

Subscribe to this mod's changes

check-links is a skill published in the GitHub repository ekline-io/ekline-docs-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 50 tokens to every session and 716 once invoked, about $0.0003 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 2026-08-31.

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check-links