What is openspec-constitution-guard?

A project setup tool that reads AGENTS.md instruction files and adds their testing and quality rules to OpenSpec, a workflow for planning and applying code changes.

Use it when starting OpenSpec, updating AGENTS.md files, or checking whether OpenSpec uses the latest project quality requirements.

It prevents OpenSpec checks from overlooking rules specific to the project. It also keeps those checks current when instruction files change.

openspec-constitution-guard — Skill by cyberelf/agent

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 cyberelf/agent_skills --skill openspec-constitution-guard

Clone the repo

git clone --depth 1 https://github.com/cyberelf/agent_skills

Made for: Claude Code, Codex.

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/cyberelf/agent_skills/openspec-constitution-guard/github.svg)](https://agentmods.dev/skills/cyberelf/agent_skills/openspec-constitution-guard)

Your own site

<a href="https://agentmods.dev/skills/cyberelf/agent_skills/openspec-constitution-guard"><img src="https://agentmods.dev/badge/skills/cyberelf/agent_skills/openspec-constitution-guard/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/cyberelf/agent_skills/openspec-constitution-guard"><img src="https://agentmods.dev/badge/skills/cyberelf/agent_skills/openspec-constitution-guard.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,301 The whole file, excluding the scripts and references it only reads on demand.

Security scan C 1 finding. 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	$0.00072	$0.03301
Opus 5.5	$0.00029	$0.01320
Sonnet 5.5	$0.00014	$0.00660
Haiku 4.5	$0.00007	$0.00330

Measured 2mo ago against content hash 0308aacff262, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

openspec-constitution-guard scanned grade C with 1 finding 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

2. Look for `<!-- CONSTITUTION-GUARD:START` marker in the config file 3. If marker is missing → first-time setup needed 4. If AGENTS.md files have changed since `Last Updated` date → refresh needed ## Workflow ### Step 1

skills/openspec-constitution-guard/SKILL.md · 428 lines

How it starts

The opening of the file, as written. The whole thing — 428 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenSpec Constitution Guard

This skill ensures OpenSpec workflows enforce project-specific quality assurance criteria derived from AGENTS.md constitution files by injecting them into openspec/config.yaml.

Purpose

OpenSpec workflows (/opsx:apply, /opsx:verify, /opsx:archive, etc.) include generic validation. This skill enriches them with project-specific quality gates extracted from AGENTS.md files across the workspace, ensuring all artifacts pass the project's defined testing and QA criteria before handoff.

When to Use

Trigger this skill when:

Initializing openspec for the first time in a project (openspec init)
An AGENTS.md file is created, modified, or deleted in the project
User explicitly requests to sync constitution quality gates with openspec config
Validating that openspec configuration is up-to-date with constitution requirements

Detection: When to Run

To detect if guards need composition:

Check if openspec/config.yaml exists
Look for <!-- CONSTITUTION-GUARD:START marker in the config file
If marker is missing → first-time setup needed
If AGENTS.md files have changed since Last Updated date → refresh needed

Workflow

Step 1: Locate All Constitution Files

Find all AGENTS.md files in the workspace:

find . -name "AGENTS.md" -type f | grep -v node_modules | grep -v .venv | grep -v target | grep -v openspec/AGENTS.md

Exclude openspec/AGENTS.md as it contains OpenSpec usage instructions already referenced by the system, not project-specific quality criteria.

Read each remaining file to understand its scope (root project, backend, frontend, specific module, etc.).

Step 2: Read and Understand Quality Criteria

For each AGENTS.md file, identify sections related to quality assurance. Look for:

Headings containing: "Quality", "Testing", "Checks", "Validation", "Assurance", "Checklist"
Command examples (typically in backticks or code blocks)
Goals or acceptance criteria (e.g., "Zero errors", "All tests pass")
Architecture patterns and coding standards that should be enforced

Read the full file on GitHub · 428 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.

2mo ago First seen · 428 lines · 72 tokens per session scan C 0308aacff262

Subscribe to this mod's changes

openspec-constitution-guard is a skill published in the GitHub repository cyberelf/agent_skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 72 tokens to every session and 3,301 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Building agents

openspec-constitution-guard next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
openspec-constitution-guardcyberelf/agent_skills	Skill	2	2mo ago	MIT	C	72	Claude Code, Codex
imagegenopenai/codex	Skill	134k	today	Apache-2.0	A	113	Codex
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	today	MIT	A	200	Claude Code, Codex
playwright-climicrosoft/playwright	Skill	99k	today	Apache-2.0	A	19	Claude Code
systematic-debuggingobra/superpowers	Skill	314k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	today	MIT	A	95	Claude Code
chat-pet-sprite-creationmicrosoft/vscode	Skill	195k	today	MIT	A	53	Claude Code, Codex

openspec-constitution-guard