Spec Kit is an open-source toolkit for defining software requirements and plans before implementation with an AI coding agent. It is used by developers and organizations following a spec-driven development process.
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 skills add github/spec-kit --skill add-community-extensiongit clone --depth 1 https://github.com/github/spec-kitWrote 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.
[](https://agentmods.dev/skills/github/spec-kit/add-community-extension)<a href="https://agentmods.dev/skills/github/spec-kit/add-community-extension"><img src="https://agentmods.dev/badge/skills/github/spec-kit/add-community-extension/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.
<a href="https://agentmods.dev/skills/github/spec-kit/add-community-extension"><img src="https://agentmods.dev/badge/skills/github/spec-kit/add-community-extension.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Snyk warn
- NVIDIA SkillSpector pass
- Socket pass
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 | $0.00063 | $0.01597 |
| Opus 5.5 | $0.00025 | $0.00639 |
| Sonnet 5.5 | $0.00013 | $0.00319 |
| Haiku 4.5 | $0.00006 | $0.00160 |
Grade A, and why
add-community-extension 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 1mo 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 — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add Community Extension
Process an extension submission issue and add or update it in the community catalog.
When to Use
- A new
[Extension]submission issue is filed - An existing extension submits an update issue (new version, changed metadata)
- You need to add or update a community extension in
extensions/catalog.community.jsonanddocs/community/extensions.md
Procedure
1. Fetch the submission issue
Read the GitHub issue to extract all metadata:
- Extension ID, name, version, description, author
- Repository URL, download URL, homepage, documentation, changelog
- License, required spec-kit version, optional tool dependencies
- Number of commands and hooks
- Tags
2. Validate against publishing rules
Check all of the following (per extensions/EXTENSION-PUBLISHING-GUIDE.md):
| Check | How |
|---|---|
| Repository exists and is public | Fetch the repository URL |
extension.yml manifest present |
Confirm in repo file listing |
| README.md present | Confirm in repo file listing |
| LICENSE file present | Confirm in repo file listing |
| GitHub release exists matching version | Check releases on the repo page |
| Download URL is accessible | Verify it follows archive/refs/tags/vX.Y.Z.zip pattern and release exists |
| Extension ID is lowercase-with-hyphens only | Regex: ^[a-z][a-z0-9-]*$ |
| Version follows semver | Format: X.Y.Z |
| Submission checklists are all checked | Confirm in issue body |
3. Determine if this is an add or update
Search extensions/catalog.community.json for the extension ID.
- Not found → this is a new addition. Proceed to step 4.
- Found → this is an update. Proceed to step 4 but replace the existing entry in-place instead of inserting.
4. Add or update extensions/catalog.community.json
New extension: Insert the entry in alphabetical order by extension ID.
Update: Replace the existing entry in-place. Update only the fields that changed (typically version, download_url, description, provides, requires, tags, updated_at). Preserve created_at and downloads/stars from the existing entry.
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.
- 1mo ago First seen · 175 lines · 63 tokens per session scan A 3061dc39dfd4
add-community-extension is a skill published in the GitHub repository github/spec-kit (141,437 stars, last pushed today), licensed MIT. It adds 63 tokens to every session and 1,597 once invoked, about $0.0003 per session on Opus 5.5. 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
openspec-bulk-archive-change
Archive multiple completed OpenSpec changes at once. Use when archiving several parallel changes. Also use for a plural archive request - "openspec bulk-archive", "opsx bulk-archive", "openspec archive all", or "openspec archive these changes".
openspec-explore
Enter OpenSpec explore mode - a thinking partner for exploring ideas, investigating problems, and clarifying requirements in a project that uses OpenSpec. Use when the user wants to think through something before or during an OpenSpec change. Also use when the user says "openspec explore" or "opsx explore".
openspec-archive-change
Archive a completed OpenSpec change in the experimental workflow. Use when the user wants to finalize and archive a change after implementation is complete. Also use when the user says "openspec archive" or "opsx archive".
openspec-onboard
Guided onboarding for OpenSpec - walk through a complete workflow cycle with narration and real codebase work. Also use when the user says "openspec onboard" or "opsx onboard".
openspec-sync-specs
Sync delta specs from an OpenSpec change to main specs. Use when the user wants to update main specs with changes from a delta spec, without archiving the change. Also use when the user says "openspec sync" or "opsx sync".
openspec-verify-change
Verify implementation matches OpenSpec change artifacts. Use when the user wants to validate that implementation is complete, correct, and coherent before archiving. Also use when the user says "openspec verify" or "opsx verify".