OpenSpec: Skill for Claude Code

.agents/skills/verify-openspec-docs/SKILL.md

verify-openspec-docs is a skill for Claude Code from Fission-AI/OpenSpec. It costs 68 tokens per session (956 once invoked), scanned A, original, MIT.

A documentation fact-checking workflow for OpenSpec, a system that uses specification files to guide code changes. It uses a fresh reviewer to rerun commands and compare claims with the source.

In plain words
What is it for?
Checking a page, section, or list of changed claims in OpenSpec documentation.
Why use it?
It catches incorrect instructions and unsupported claims before documentation is published.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: mentions subagents; installed under .agents/ (shared by several agents).

This is Fission-AI/OpenSpec's own configuration. It tells Claude Code how to work on OpenSpec itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything OpenSpec configures →

About the project

OpenSpec is a specification-driven development framework that records software requirements and implementation plans as readable Markdown artifacts. It helps developers and AI coding assistants agree on what should be built before code is written, including work spanning multiple repositories. The catalogue add-ons provide workflow skills and instructions for using OpenSpec.

Fission-AI/OpenSpec · 74,064 stars · on GitHub · openspec.dev

Reuse

Borrowing it

Nothing to install: this file belongs to Fission-AI/OpenSpec. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Fission-AI/OpenSpec/main/.agents/skills/verify-openspec-docs/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Fission-AI/OpenSpec

Made for: Claude Code.

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.

agentmods badge for verify-openspec-docs

README.md
[![agentmods](https://agentmods.dev/badge/skills/fission-ai/openspec/verify-openspec-docs/github.svg)](https://agentmods.dev/skills/fission-ai/openspec/verify-openspec-docs)
Your own site
<a href="https://agentmods.dev/skills/fission-ai/openspec/verify-openspec-docs"><img src="https://agentmods.dev/badge/skills/fission-ai/openspec/verify-openspec-docs/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.

agentmods 80×15 button for verify-openspec-docs

Your own site · 80×15
<a href="https://agentmods.dev/skills/fission-ai/openspec/verify-openspec-docs"><img src="https://agentmods.dev/badge/skills/fission-ai/openspec/verify-openspec-docs.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 956 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. Third-party audits
  • Socket pass 21 Aug 2026
  • Snyk warn 21 Aug 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00068 $0.00956
Opus 5.5 $0.00027 $0.00382
Sonnet 5.5 $0.00014 $0.00191
Haiku 4.5 $0.00007 $0.00096

Measured 2mo ago against content hash a3fa53a4ce37, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

verify-openspec-docs 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 2mo 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.

.agents/skills/verify-openspec-docs/SKILL.md · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verify OpenSpec docs

Check finished docs prose against reality. The point of a fresh context is that the reviewer hasn't watched the prose get written, so it can't be talked into the author's assumptions.

This skill runs only when the user asks for it. Drafting is owned by write-openspec-docs; don't invoke this from inside a drafting session unless the user requests a verification pass.

Scope the run

  1. Confirm the target: a page, one ## section, or a list of changed claims. If invoked without a target, ask.
  2. Read the README at the root of the docs tree the target lives in; its invariants and page map are part of what gets checked.
  3. One subagent per unit (one ## section, or the stated claim list). A full page is several subagents, run in parallel.

Spawn the reviewer

General-purpose subagent. Subagents don't inherit skills, so the prompt hands the reviewer everything by path. Fill every placeholder, make every path absolute, and send:

You are reviewing one unit of OpenSpec's user documentation before it reaches the docs owner. Be the two hardest readers it will meet: a skeptical developer reading it cold, and a fact-checker with the repo open.

Repo root: <ABSOLUTE REPO ROOT>. Use absolute paths with every tool.

Read first:
1. <DOCS TREE ROOT>/README.md: the page map and standing invariants.
2. <ABSOLUTE REPO ROOT>/.agents/skills/write-openspec-docs/writing.md: the house writing rules.
3. <PAGE PATH>: review only <the section "<HEADING>" | these changed claims: <LIST>>; read the rest of the page for context.

Then check, in this order:

1. Facts. Every command, flag, path, config key, output block, default, and behavior claim. Re-run the terminal commands shown: read-only commands anywhere, anything that mutates state in a scratch directory or not at all. Commands for the AI chat surface (like /opsx:propose) can't run in a shell; verify their names and behavior against the skill sources this repo ships. Check names against src/ and the CLI's own --help. An output block must match what the command actually prints.
2. Examples. Any example spec or change must pass `openspec validate`. Run it when the example exists on disk.
3. Structure. Flag anything that re-explains a topic whose canonical home is another page, or breaks a rule the docs tree's README states.
4. Job fit. Does the unit serve the page's stated job (the one-line statement under the title, if present)? Does the arriving reader get what they came for quickly?
5. Trust and slop. Flag: hype or comfort adjectives (easy, simple, powerful, seamless), claims with no shown evidence, vague generalization where a specific fact belongs, binary contrasts ("not X, it's Y"), colon reveals, importance puffery, summary endings, em dashes, bullet lists that should be prose, and three parallel punchy sentences in a row.

Report findings only, most severe first. For each: quote the line, say what is wrong, and give the fix in one line. For every fact you verified, say how (the command you ran, or the file and line you checked). List any claim you could not verify and why. Do not rewrite the unit. If the unit is clean, say so and list exactly what you verified.

Read the full file on GitHub · 50 lines

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.

  1. 2mo ago First seen · 50 lines · 68 tokens per session scan A a3fa53a4ce37

Subscribe to this mod's changes

verify-openspec-docs is a skill published in the GitHub repository Fission-AI/OpenSpec (74,064 stars, last pushed yesterday), licensed MIT. It adds 68 tokens to every session and 956 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.

Related

verify-openspec-docs compared with skills from other repositories

verify-openspec-docs next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
verify-openspec-docsFission-AI/OpenSpecSkill74kyesterdayMITA68Claude Code
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code-reviewgithub/spec-kitSkill148kyesterdayMITA54Claude Code
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openprd-sharedmileson/openprdSkill501mo agoMITA74Claude Code, Codex
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