Claude Skill Changes Tracker

Daily diff watcher for Claude Code Skills across the official Anthropic repo and the top community repos. Find out — automatically, every day — which Skills were added, updated, or removed since yesterday.

What does Claude Skill Changes Tracker do?

The Claude Code Skills ecosystem moved from "interesting idea" to "production toolchain" in months. The official Anthropic Skills repo keeps growing, and dozens of community Skills repos publish their own SKILL.md files weekly. There is no central changelog.

This Actor solves that. It scans a configurable watchlist of GitHub repositories (default: the Anthropic-canonical + 4 top community Skills repos), finds every SKILL.md file in each repo's default branch, and diffs the manifest against the previous run. The result is a structured changelog: which Skills are brand new, which were updated (content hash or size changed), and which were removed.

It is the time-series companion to the point-in-time claude-code-skill-finder Actor (#13 in Ian Mu's 100-actor portfolio). When scheduled on the Apify platform, it gives you a daily changelog with zero infrastructure of your own — leveraging Apify's scheduling, key-value-store-backed snapshots, and API access.

Why use Claude Skill Changes Tracker?

• Skill maintainers: get a notification when a competing Skill releases a new version, or when the Anthropic official repo bumps design-html or frontend-design
• Developer-tools investors: track the velocity of the Claude Code Skills ecosystem — is community contribution accelerating?
• Tutorial creators: spot brand-new Skills the day they land so your content is first
• Product managers at companies building on Claude Code: know the day a new official Skill changes your integration assumptions
• Security teams: audit removed Skills (deprecated for a reason?) and updated Skills (what changed?)

How to use Claude Skill Changes Tracker

1. Open the Input tab. The default watchlist tracks 5 high-signal repos.
2. (Optional) Add a githubToken Apify secret to raise GitHub's anonymous rate limit (60/hour) to 5000/hour.
3. (Optional) Add or remove repos from watchlist.
4. Click Start. The first run has no baseline — every Skill is reported as new and the manifest is cached.
5. Schedule the Actor daily (e.g. 06:00 UTC). From the second run onward, the dataset returns only deltas: new, updated, removed.
6. Pipe the dataset into Slack, email, or a database via Apify's webhooks / integrations.

Input

Field	Type	Description
watchlist	string[]	Array of owner/repo GitHub paths to monitor. Defaults to 5 curated Skills repos.
cacheKeyPrefix	string	Prefix for per-repo manifests in the key-value store. Default skill-cache-.
githubToken	string (secret)	Optional GitHub PAT to raise the API rate limit.
branchHint	string	Force a non-default branch globally. Empty = auto-detect per repo.

Example input:

{
  "watchlist": [
    "anthropics/skills",
    "obra/superpowers",
    "wshobson/agents"
  ],
  "cacheKeyPrefix": "skill-cache-",
  "githubToken": "ghp_xxx"
}

Output

Each dataset item:

{
  "changeType": "updated",
  "skillName": "design-html",
  "skillPath": "skills/design-html/SKILL.md",
  "repo": "anthropics/skills",
  "branch": "main",
  "sizeBytes": 4200,
  "previousSizeBytes": 3850,
  "sizeDeltaBytes": 350,
  "sha": "3a7c2d1...",
  "previousSha": "1f9e8b4...",
  "url": "https://github.com/anthropics/skills/blob/main/skills/design-html/SKILL.md",
  "detectedAt": "2026-05-21T06:00:00.000Z"
}

You can download the dataset in various formats such as JSON, HTML, CSV, or Excel. A Markdown summary report (skill-changes-report.md) is also written to the key-value store after every run.

Data table

Field	Type	Meaning
changeType	string	new, updated, or removed
skillName	string	Directory name housing the SKILL.md (e.g. design-html)
skillPath	string	Full path inside the repo (e.g. skills/design-html/SKILL.md)
repo	string	owner/repo source
branch	string	Branch the diff was computed against
sizeBytes	number	Current SKILL.md byte size (null for removed)
previousSizeBytes	number	Prior-run byte size (null for new)
sizeDeltaBytes	number	Signed delta
sha	string	Git blob SHA — proxy for content hash
url	link	Direct GitHub link to the SKILL.md
detectedAt	date	Timestamp of this run

Pricing / Cost estimation

• Free trial: 5 daily runs, 5-repo watchlist (covers the default config)
• Daily delta subscription: $1.50/month for daily diffs of up to 10 repos
• Wide watchlist: $0.001 per repo scanned per run, so a 50-repo watchlist costs around $0.05/run

Each run uses around 0.001 Compute Units. The GitHub API is free up to 60 requests/hour anonymous and 5000/hour with a token.

Tips and advanced options

• First-run cost: every Skill is reported new on run #1 because there is no baseline. Expect a one-time spike.
• Pair with vscode-ai-extension-popularity-tracker (sibling Actor in the 100-actor portfolio) to build an end-to-end "AI coding tool intelligence" pipeline
• Add your own repo: if you maintain a Skills repo, include it in watchlist for a free daily audit of your own changes
• Use webhooks: configure an Apify webhook on RUN_SUCCEEDED to push changeType=new rows directly into Slack
• Forks vs upstream: this Actor does not deduplicate Skills that exist in both a fork and its upstream. If you want a deduped global Skills view, use claude-code-skill-finder (the point-in-time companion).

FAQ, disclaimers, and support

Q: How does it detect "updated" vs "new"? Each run records a manifest of { skillPath → { sizeBytes, sha } }. Next run compares the new manifest to the cached one. Any SHA or size change = updated. New path = new. Missing path = removed.

Q: Why filename + size + SHA, not full content? Cost. Fetching every SKILL.md body across 50 repos every day wastes bandwidth. The Git blob SHA is a perfect content hash — same SHA means byte-identical content.

Q: Will it miss content changes that don't change size? No. The Git blob SHA changes on any byte-level change, even ones that preserve size.

Q: What if a repo has 100+ SKILL.md files in subdirectories? The tree API returns up to 100k entries. If truncated=true is reported, the Actor logs a warning. Practical Skills repos stay well under this cap.

Q: Can I track private repos? Yes — pass a githubToken with appropriate scope via Apify secrets.

Q: Legality? This Actor only reads public GitHub metadata (repo tree + file size + SHA), which is explicitly allowed by GitHub's ToS for both authenticated and anonymous use.

For issues, feature requests, or custom watchlists, open the Issues tab on this Actor.

Built by Ian Mu — github.com/ianymu, author of claude-verify-before-stop. Part of a 100-Actor AI / dev-tools intelligence portfolio.