Detrix MCP Server Adds Runtime Debugging to AI Coding Agents

What Detrix Does

Detrix is an MCP (Model Context Protocol) server that connects AI coding agents to your application's debugger via DAP (Debug Adapter Protocol). It allows agents to observe running code without stopping execution, using logpoints—breakpoints that capture values without pausing.

Key Features

• Observe any variable at any line without specifying line numbers (find_variable)
• Capture stack traces, memory snapshots, and evaluate expressions
• Throttle, sample, or rate-limit captures on hot paths
• Observations expire automatically—nothing leaks into production
• Runs locally by default—no cloud dependency, no data leaves your machine
• Works in Docker/cloud—agent connects to wherever the daemon is, no VPN needed

Example Use Case

In the source example, a Go microservice in Docker was reporting wildly inflated revenue. The agent used Detrix to:

1. Read the source code and spot dead unit-conversion code
2. Wake the service via Detrix
3. Observe txn.Amount, txn.Unit, and total variables in the running container
4. Identify that txn.Amount = 8957 with txn.Unit = "cents" was being summed as dollars instead of converting to $89.57
5. Fix the client code and report the API contract change upstream

Setup

For Claude Code:

brew install flashus/tap/detrix && detrix init && claude mcp add --scope user detrix -- detrix mcp

For any other MCP-compatible agent, add to .mcp.json:

{
  "mcpServers": {
    "detrix": {
      "command": "detrix",
      "args": ["mcp"]
    }
  }
}

Add one line to your app:

import detrix
detrix.init(name="my-app") # sleeps until the agent needs it

Claude Code Skill

There's a Claude Code skill that changes Claude's default debugging behavior—once installed, Claude reaches for Detrix before suggesting print statements. It also has enable_from_diff: point it at a git diff with print statements someone already added and it converts them to observations automatically.

Install the skill:

mkdir -p ~/.claude/skills/detrix && cp skills/detrix/* ~/.claude/skills/detrix/

GitHub: https://github.com/flashus/detrix