Code Reasoning MCP Server

Thought Revision is used when a previous reasoning step is found to be incorrect or suboptimal. To perform a revision, set is_revision to true and specify the revises_thought field with the thought_number of the error being corrected.

{
  "thought": "On second thought, I overlooked the fact that the data might be already partially sorted... Mergesort would be a better choice.",
  "thought_number": 3,
  "total_thoughts": 5,
  "is_revision": true,
  "revises_thought": 1,
  "next_thought_needed": true
}

All prompts support a working_directory parameter. Setting this allows Claude to have clear context about your project location, reference project files easily, and simplify file access via filesystem tools.

Example values:

• macOS/Linux: ~/projects/my-app or /Users/username/projects/my-app
• Windows: C:\Users\username\projects\my-app

The server uses a streamlined logging approach via console.error() to ensure compatibility with the MCP protocol (which expects logs on stderr).

• Output Destination: All logs are written to stderr.
• Debug Mode: Verbose debug logs are only emitted when the --debug flag is provided at startup.
• Limitations: There is no support for custom log directories or log file rotation.

Thought Branching allows the reasoning process to diverge from a previous thought to explore alternative solutions or architectures. To branch, set branch_from_thought to the index of the thought you are diverging from, and provide a unique branch_id to identify this new path.

{
  "thought": "Alternative Approach: We could also consider batch processing with scheduled ETL jobs instead of real-time processing.",
  "thought_number": 3,
  "total_thoughts": 6,
  "branch_from_thought": 1,
  "branch_id": "BatchETL",
  "next_thought_needed": true
}

The MCP regression harness (located in test/mcp-regression.test.ts) verifies the server's MCP contract end-to-end by exercising the published stdio entry point (dist/index.js) using the official SDK client.

Currently, the suite covers:

• Tool discovery: Verifying tools/list works correctly.
• Tool execution: Testing both happy-path calls and validation-error scenarios for the code-reasoning tool.
• Prompt management: Testing prompt discovery, prompt rendering, and completion persistence for the bug-analysis prompt.

You can extend this suite by adding additional request flows within the existing test runner.

The Code Reasoning MCP server persists argument values between sessions to reduce repetitive data entry.

Key Behaviors

• Value Storage: When you use a prompt, argument values are saved to a JSON file in the ~/.code-reasoning/ directory, organized by prompt name.
• Global Values: Certain parameters, such as working_directory, are stored globally and shared across all prompts. You only need to set these once.
• Automatic Retrieval: When re-using a prompt, the dialog fields will be pre-filled with your previously saved values. You can override these at any time by entering new data.

Managing Stored Values

Stored values are located at: ~/.code-reasoning/prompt_values.json

To reset all stored prompt values, delete this file or modify it directly.

To integrate the Code-Reasoning MCP server into VS Code, update your user settings (settings.json) to include the server configuration under the mcp.servers key. Alternatively, you can configure it for a specific project by creating a .vscode/mcp.json file in your workspace root.

// VS Code User Settings (settings.json)
{
  "editor.fontFamily": "Fira Code, monospace",
  "editor.fontSize": 14,
  "mcp": {
    "servers": {
      "code-reasoning": {
        "command": "code-reasoning",
        "args": ["--debug"]
      }
    }
  }
}

// Workspace-specific configuration (.vscode/mcp.json)
{
  "servers": {
    "code-reasoning": {
      "command": "code-reasoning",
      "args": ["--debug"]
    }
  }
}

To integrate the Code-Reasoning MCP Server into Claude Desktop, add it to your mcpServers configuration file using the following JSON structure:

{
  "mcpServers": {
    "code-reasoning": {
      "command": "npx",
      "args": ["-y", "@mettamatt/code-reasoning"]
    }
  }
}

To use the Code-Reasoning MCP Server within Claude Desktop, add it to your claude_desktop_config.json file.

Config File Locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Configuration Format: Ensure the command is set to code-reasoning. You can pass arguments like --debug via the args array.

{
  "mcpServers": {
    "code-reasoning": {
      "command": "code-reasoning",
      "args": ["--debug"]
    }
  }
}