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/idor-testingnpx skills add zebbern/claude-code-guide --skill idor-testinggit 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 | $0.00075 | $0.03101 |
| Opus 5 | $0.00037 | $0.01550 |
| Sonnet 5 | $0.00015 | $0.00620 |
| Haiku 4.5 | $0.00007 | $0.00310 |
Grade A, and why
idor-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 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.
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.
How it starts
The opening of the file, as written. The whole thing — 443 lines — stays where its author put it; the contents beside it link to each section on GitHub.
IDOR Vulnerability Testing
Purpose
Provide systematic methodologies for identifying and exploiting Insecure Direct Object Reference (IDOR) vulnerabilities in web applications. This skill covers both database object references and static file references, detection techniques using parameter manipulation and enumeration, exploitation via Burp Suite, and remediation strategies for securing applications against unauthorized access.
Inputs / Prerequisites
- Target Web Application: URL of application with user-specific resources
- Multiple User Accounts: At least two test accounts to verify cross-user access
- Burp Suite or Proxy Tool: Intercepting proxy for request manipulation
- Authorization: Written permission for security testing
- Understanding of Application Flow: Knowledge of how objects are referenced (IDs, filenames)
Outputs / Deliverables
- IDOR Vulnerability Report: Documentation of discovered access control bypasses
- Proof of Concept: Evidence of unauthorized data access across user contexts
- Affected Endpoints: List of vulnerable API endpoints and parameters
- Impact Assessment: Classification of data exposure severity
- Remediation Recommendations: Specific fixes for identified vulnerabilities
Core Workflow
1. Understand IDOR Vulnerability Types
Direct Reference to Database Objects
Occurs when applications reference database records via user-controllable parameters:
# Original URL (authenticated as User A)
example.com/user/profile?id=2023
# Manipulation attempt (accessing User B's data)
example.com/user/profile?id=2022
Direct Reference to Static Files
Occurs when applications expose file paths or names that can be enumerated:
# Original URL (User A's receipt)
example.com/static/receipt/205.pdf
# Manipulation attempt (User B's receipt)
example.com/static/receipt/200.pdf
2. Reconnaissance and Setup
Create Multiple Test Accounts
Account 1: "attacker" - Primary testing account
Account 2: "victim" - Account whose data we attempt to access
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 · 443 lines · 75 tokens per session scan A 6f7c16c24bdf
idor-testing is a skill published in the GitHub repository zebbern/claude-code-guide (4,597 stars, last pushed yesterday), licensed MIT. It adds 75 tokens to every session and 3,101 once invoked, about $0.0004 per session on Opus 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.
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