Niro — Claude Code MCP server: what it does, how to install
Niro tests a running app like an attacker, proves exploitable security bugs, and prepares fixes as pull requests. It covers web apps, APIs, and MCP servers.
Open on GitHubWhat Niro does
Niro coordinates an attacker agent and a developer agent. The first probes the running application and must reproduce a finding before it counts; the second patches issues it can safely address and records validation evidence, usually in a regression test. The result is a set of focused pull requests grouped by root cause.
The run can prepare the app by creating test state, users, and data needed for the attack. HTTP targets are limited through scope.yaml, while attack tools run inside a sandbox with network-level egress controls. From the project root, install it with curl -fsSL https://raw.githubusercontent.com/apxlabs-ai/niro/main/install.sh | sh, then start niro fix. The --autonomous flag grants full current-user host access without approval prompts, so its threat model deserves review before use. Niro opens the pull requests; you decide what gets merged.
What it helps with
- probe an application for exploitable security bugs
- reproduce findings with runnable proof
- create users and test data for blocked attack paths
- turn confirmed issues into focused pull requests
- record regression evidence for proposed fixes
Example prompts for the agent
- Run a security test against the application and prove every exploitable finding.
- Test the HTTP surfaces allowed by
scope.yaml, then prepare fixes as pull requests. - Review the confirmed vulnerabilities and add regression tests for the fixes.
How to install Niro
Install
The MCP registry has no launch command for it: see the repository README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Niro
How do I install Niro in Claude Code?
From the project root, run curl -fsSL https://raw.githubusercontent.com/apxlabs-ai/niro/main/install.sh | sh, then start it with niro fix.
What does Niro do?
It prepares a test environment, attacks a running app, verifies real vulnerabilities, and creates pull requests with fixes and validation evidence.
What does the --autonomous mode allow?
It runs without approval prompts and gives the agent full access to the current user's host. Review the agent CLI threat model before using it.
