jose-critical-header-validation-conformance

jose-critical-header-validation-conformance is a skill for Claude Code, Codex from mouadja02/skills. It costs 85 tokens per session (2,346 once invoked), scanned A, original, no licence file.

A security-checking skill for software that handles JWS or JWT tokens, signed data formats used to carry claims between systems. It focuses on the crit header, which marks extensions that must be understood, and on rejecting malformed or unsupported values safely.

In plain words
What is it for?
Use it to test critical-header handling across different software environments, including unknown extensions, standard names listed as critical, dangling entries, duplicates, and the RFC 7797 b64 option.
Why use it?
It helps prevent a token library or service from silently ignoring security instructions, accepting duplicate entries, or mishandling the unencoded-payload option.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit Use it to test critical-header handling across different software environments, including unknown extensions, standard names listed as critical, dangling entries, duplicates, and the RFC 7797 b64 option.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mouadja02/skills/jose-critical-header-validation-conformance
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 mouadja02/skills --skill jose-critical-header-validation-conformance
Clone the repo
git clone --depth 1 https://github.com/mouadja02/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.

agentmods badge for jose-critical-header-validation-conformance

README.md
[![agentmods](https://agentmods.dev/badge/skills/mouadja02/skills/jose-critical-header-validation-conformance/github.svg)](https://agentmods.dev/skills/mouadja02/skills/jose-critical-header-validation-conformance)
Your own site
<a href="https://agentmods.dev/skills/mouadja02/skills/jose-critical-header-validation-conformance"><img src="https://agentmods.dev/badge/skills/mouadja02/skills/jose-critical-header-validation-conformance/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 jose-critical-header-validation-conformance

Your own site · 80×15
<a href="https://agentmods.dev/skills/mouadja02/skills/jose-critical-header-validation-conformance"><img src="https://agentmods.dev/badge/skills/mouadja02/skills/jose-critical-header-validation-conformance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 85 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,346 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 unknown 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 $0.00085 $0.02346
Opus 5.5 $0.00034 $0.00938
Sonnet 5.5 $0.00017 $0.00469
Haiku 4.5 $0.00009 $0.00235

Measured 1mo ago against content hash a2a03d572b5b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

jose-critical-header-validation-conformance 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.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/validate_jose_crit.py, tests/test_jose_crit.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/api-backend/jose-critical-header-validation-conformance/SKILL.md · 158 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

4 files 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.

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. 1mo ago First seen · 158 lines · 85 tokens per session scan A a2a03d572b5b

Subscribe to this mod's changes

jose-critical-header-validation-conformance is a skill published in the GitHub repository mouadja02/skills (11 stars, last pushed 3d ago), with no licence file. It adds 85 tokens to every session and 2,346 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 2026-09-10.

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