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 agentmods add skills/zebbern/claude-code-guide/broken-authenticationnpx skills add zebbern/claude-code-guide --skill broken-authenticationgit clone --depth 1 https://github.com/zebbern/claude-code-guideWhat 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 | $0.00067 | $0.03045 |
| Opus 5 | $0.00034 | $0.01522 |
| Sonnet 5 | $0.00013 | $0.00609 |
| Haiku 4.5 | $0.00007 | $0.00304 |
Grade A, and why
broken-authentication scanned grade A 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 2d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
response = requests.get("https://target.com/login") Copies of this mod
1 near-identical copy found in the catalogue:
- Broken Authentication Testing — 92% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 477 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Broken Authentication Testing
Purpose
Identify and exploit authentication and session management vulnerabilities in web applications. Broken authentication consistently ranks in the OWASP Top 10 and can lead to account takeover, identity theft, and unauthorized access to sensitive systems. This skill covers testing methodologies for password policies, session handling, multi-factor authentication, and credential management.
Prerequisites
Required Knowledge
- HTTP protocol and session mechanisms
- Authentication types (SFA, 2FA, MFA)
- Cookie and token handling
- Common authentication frameworks
Required Tools
- Burp Suite Professional or Community
- Hydra or similar brute-force tools
- Custom wordlists for credential testing
- Browser developer tools
Required Access
- Target application URL
- Test account credentials
- Written authorization for testing
Outputs and Deliverables
- Authentication Assessment Report - Document all identified vulnerabilities
- Credential Testing Results - Brute-force and dictionary attack outcomes
- Session Security Analysis - Token randomness and timeout evaluation
- Remediation Recommendations - Security hardening guidance
Core Workflow
Phase 1: Authentication Mechanism Analysis
Understand the application's authentication architecture:
# Identify authentication type
- Password-based (forms, basic auth, digest)
- Token-based (JWT, OAuth, API keys)
- Certificate-based (mutual TLS)
- Multi-factor (SMS, TOTP, hardware tokens)
# Map authentication endpoints
/login, /signin, /authenticate
/register, /signup
/forgot-password, /reset-password
/logout, /signout
/api/auth/*, /oauth/*
Capture and analyze authentication requests:
POST /login HTTP/1.1
Host: target.com
Content-Type: application/x-www-form-urlencoded
username=test&password=test123
Phase 2: Password Policy Testing
Evaluate password requirements and enforcement:
# Test minimum length (a, ab, abcdefgh)
# Test complexity (password, password1, Password1!)
# Test common weak passwords (123456, password, qwerty, admin)
# Test username as password (admin/admin, test/test)
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.
- 2d ago First seen · 477 lines · 67 tokens per session scan A 36289965b69c
broken-authentication is a skill published in the GitHub repository zebbern/claude-code-guide (4,597 stars, last pushed yesterday), licensed MIT. It adds 67 tokens to every session and 3,045 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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