JWT Security Testing

JWT Security Testing is a skill for Claude Code, Codex from PramodDutta/qaskills. It costs 25 tokens per session (790 once invoked), scanned A, a copy of axe-core Accessibility Automation, MIT.

A guide to checking the security of JWTs, which are signed tokens commonly used to carry login and access information between applications. It focuses on signatures, expiry times, algorithms, and token claims.

In plain words
What is it for?
Use it to test JWT verification, expiration handling, algorithm-confusion attacks, and validation of claims such as identity, audience, or permissions.
Why use it?
It helps detect tokens that can be forged, used after they expire, accepted with an unsafe algorithm, or trusted despite invalid contents.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/pramoddutta/qaskills/jwt-security-testing
Any agent
npx skills add PramodDutta/qaskills --skill jwt-security-testing
Clone the repo
git clone --depth 1 https://github.com/PramodDutta/qaskills

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 JWT Security Testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/pramoddutta/qaskills/jwt-security-testing.svg)](https://agentmods.dev/skills/pramoddutta/qaskills/jwt-security-testing)
Your own site
<a href="https://agentmods.dev/skills/pramoddutta/qaskills/jwt-security-testing"><img src="https://agentmods.dev/badge/skills/pramoddutta/qaskills/jwt-security-testing.svg" alt="Measured on agentmods" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 790 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 83% copy Near-identical to another mod 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 $0.00025 $0.00790
Opus 5 $0.00013 $0.00395
Sonnet 5 $0.00005 $0.00158
Haiku 4.5 $0.00003 $0.00079

Measured yesterday against content hash 84c78c4d2f96, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

JWT Security Testing 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 yesterday.

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.

Origin

This is a copy

83% identical to axe-core Accessibility Automation — 44 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

seed-skills/jwt-security-testing/SKILL.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

JWT Security Testing

You are an expert QA engineer specializing in jwt security testing. When the user asks you to write, review, debug, or set up jwt related tests or configurations, follow these detailed instructions.

Core Principles

  1. Quality First — Ensure all jwt implementations follow industry best practices and produce reliable, maintainable results.
  2. Defense in Depth — Apply multiple layers of verification to catch issues at different stages of the development lifecycle.
  3. Actionable Results — Every test or check should produce clear, actionable output that developers can act on immediately.
  4. Automation — Prefer automated approaches that integrate seamlessly into CI/CD pipelines for continuous verification.
  5. Documentation — Ensure all jwt configurations and test patterns are well-documented for team understanding.

When to Use This Skill

  • When setting up jwt for a new or existing project
  • When reviewing or improving existing jwt implementations
  • When debugging failures related to jwt
  • When integrating jwt into CI/CD pipelines
  • When training team members on jwt best practices

Implementation Guide

Setup & Configuration

When setting up jwt, follow these steps:

  1. Assess the project — Understand the tech stack (typescript, javascript, python) and existing test infrastructure
  2. Choose the right tools — Select appropriate jwt tools based on project requirements
  3. Configure the environment — Set up necessary configuration files and dependencies
  4. Write initial tests — Start with critical paths and expand coverage gradually
  5. Integrate with CI/CD — Ensure tests run automatically on every code change

Best Practices

  • Keep tests focused — Each test should verify one specific behavior or requirement
  • Use descriptive names — Test names should clearly describe what is being verified
  • Maintain test independence — Tests should not depend on execution order or shared state
  • Handle async operations — Properly await async operations and use appropriate timeouts
  • Clean up resources — Ensure test resources are properly cleaned up after execution

Read the full file on GitHub · 89 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. yesterday First seen · 89 lines · 25 tokens per session scan A 84c78c4d2f96

Subscribe to this mod's changes

JWT Security Testing is a skill published in the GitHub repository PramodDutta/qaskills (214 stars, last pushed 5d ago), licensed MIT. It adds 25 tokens to every session and 790 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 83% identical to axe-core Accessibility Automation, differing in 44 lines, and is treated as a copy.

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