This skill allows Claude to conduct automated fuzz testing on REST APIs. It identifies potential security flaws and robustness issues by injecting various malformed inputs, boundary values, and random data.
How It Works
Input Generation: The skill generates a diverse set of test inputs, including malformed data, boundary values, and random payloads.
API Interaction: It sends these inputs to the specified API endpoints.
Result Analysis: It analyzes the API's responses and behavior to identify vulnerabilities, crashes, and unexpected results, such as SQL injection errors or XSS vulnerabilities.
When to Use This Skill
This skill activates when you need to:
Identify potential security vulnerabilities in an API.
Test the robustness of an API against unexpected inputs.
Ensure proper input validation is implemented in an API.
Examples
Example 1: Discovering SQL Injection Vulnerability
User request: "Fuzz test the /users endpoint for SQL injection vulnerabilities."
The skill will:
Generate SQL injection payloads.
Send these payloads to the /users endpoint.
Analyze the API's responses for SQL errors or unexpected behavior indicating a SQL injection vulnerability.
Example 2: Testing Input Validation
User request: "Fuzz test the /products endpoint to check for input validation issues with price and quantity parameters."
The skill will:
Generate malformed inputs for price and quantity (e.g., negative values, extremely large numbers, non-numeric characters).
Send these inputs to the /products endpoint.
Analyze the API's responses for errors or unexpected behavior, indicating input validation failures.
Best Practices
Specificity: Be specific about the API endpoint or parameters you want to fuzz.
Context: Provide context about the expected behavior of the API.
Iteration: Run multiple fuzzing sessions with different input sets for thorough testing.
Integration
This skill can be used in conjunction with other security analysis tools to provide a more comprehensive assessment of an API's security posture. It can also be integrated into a CI/CD pipeline to automate security testing.
Converted and distributed by TomeVault — claim your Tome and manage your conversions.
1---2name: jeremylongshore-claude-code-plugins-plus-skills-api-fuzzer3description: Overview4---56## Overview78This skill allows Claude to conduct automated fuzz testing on REST APIs. It identifies potential security flaws and robustness issues by injecting various malformed inputs, boundary values, and random data.910## How It Works11121. **Input Generation**: The skill generates a diverse set of test inputs, including malformed data, boundary values, and random payloads.132. **API Interaction**: It sends these inputs to the specified API endpoints.143. **Result Analysis**: It analyzes the API's responses and behavior to identify vulnerabilities, crashes, and unexpected results, such as SQL injection errors or XSS vulnerabilities.1516## When to Use This Skill1718This skill activates when you need to:19- Identify potential security vulnerabilities in an API.20- Test the robustness of an API against unexpected inputs.21- Ensure proper input validation is implemented in an API.2223## Examples2425### Example 1: Discovering SQL Injection Vulnerability2627User request: "Fuzz test the /users endpoint for SQL injection vulnerabilities."2829The skill will:301. Generate SQL injection payloads.312. Send these payloads to the /users endpoint.323. Analyze the API's responses for SQL errors or unexpected behavior indicating a SQL injection vulnerability.3334### Example 2: Testing Input Validation3536User request: "Fuzz test the /products endpoint to check for input validation issues with price and quantity parameters."3738The skill will:391. Generate malformed inputs for price and quantity (e.g., negative values, extremely large numbers, non-numeric characters).402. Send these inputs to the /products endpoint.413. Analyze the API's responses for errors or unexpected behavior, indicating input validation failures.4243## Best Practices4445- **Specificity**: Be specific about the API endpoint or parameters you want to fuzz.46- **Context**: Provide context about the expected behavior of the API.47- **Iteration**: Run multiple fuzzing sessions with different input sets for thorough testing.4849## Integration5051This skill can be used in conjunction with other security analysis tools to provide a more comprehensive assessment of an API's security posture. It can also be integrated into a CI/CD pipeline to automate security testing.5253---54> Converted and distributed by [TomeVault](https://tomevault.io/claim/jeremylongshore) — claim your Tome and manage your conversions.55<!-- tomevault:4.0:skill_md:2026-04-11 -->
Run npx skillmds@latest add tomevault-io/jeremylongshore-claude-code-plugins-plus-skills-api-fuzzer in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.
Overview It is listed under Integrations & APIs on SkillMD.
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tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.