Predictive Debugger MCP server

Predictive Debugger

Website and docs: predictivedebugger.dev

MCP server for finding likely runtime failures in JavaScript and TypeScript. Six tools help your coding agent rank risky files, trace dependencies, inspect logs and get an independent model review with a line number and reason.

Uses the Claude Code, Codex or GitHub Copilot CLI you already have installed. Prediction calls use that CLI's model access and usage allowance. No separate API key is needed.

Setup

Requires Node.js 22 or later. For model predictions, install and sign in to at least one supported CLI. Python 3 is optional for log analysis.

1. Add the MCP server

Choose your agent below. npx downloads and runs the package automatically.

Claude Code

Run in your project on macOS, Linux or WSL:

claude mcp add --scope project predictive-debugger -- npx -y predictive-debugger@latest

On native Windows, from PowerShell:

claude mcp add --scope project predictive-debugger -- cmd /d /c npx -y predictive-debugger@latest

Use --scope user to make it available in every project.

Codex

For a user-level setup on macOS, Linux or WSL:

codex mcp add predictive-debugger -- npx -y predictive-debugger@latest

On native Windows, from PowerShell:

codex mcp add predictive-debugger -- cmd /d /c npx -y predictive-debugger@latest

For project-only setup or a longer startup timeout, see Codex configuration.

GitHub Copilot CLI

Add to .mcp.json in your project:

{
  "mcpServers": {
    "predictive-debugger": {
      "command": "npx",
      "args": ["-y", "predictive-debugger@latest"],
      "tools": ["*"]
    }
  }
}

On native Windows, use "command": "cmd" and "args": ["/d", "/c", "npx", "-y", "predictive-debugger@latest"].

For every project, see Copilot user-level setup.

2. Check the connection

Restart your agent and check /mcp for predictive-debugger and its six tools. To check that the package downloads and print its version:

npx -y predictive-debugger@latest --version

Running without --version starts a stdio server that waits for your agent's messages. See setup help for local builds and troubleshooting.

3. Ask your agent about the code

Use Predictive Debugger to find the riskiest files in src/.
Show the imports and tests connected to src/services/orders.ts.
Check src/services/orders.ts for likely runtime failures.
Find unusual entries in logs/app.log.

Tools

Shortened. The full README is on GitHub.