decision-log

An MCP server that gives AI coding agents persistent memory for architectural decisions, TODOs, and technical debt. It stores decisions in a single JSON file and exposes 7 tools that let agents log choices with full rationale, query past decisions before making new ones, detect conflicts between proposed and existing decisions, track technical debt, and get a project-wide summary — so context is never lost between sessions.

MCP Configuration

Add this to your Claude Desktop or Cursor MCP config:

{
  "mcpServers": {
    "decision-log": {
      "command": "node",
      "args": ["/absolute/path/to/dist/index.js"],
      "env": {
        "DECISION_LOG_PATH": "/optional/custom/path/decisions.json"
      }
    }
  }
}

Claude Desktop config location:

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

Installation

npm install
npm run build

Running

node dist/index.js

Environment Variables

| Variable | Description | Default | |---|---|---| | DECISION_LOG_PATH | Absolute path to the JSON file used for storage | ~/.mcp/decision-log/decisions.json |

Tools

| Tool | Description | |---|---| | log_decision | Records an architectural or technical decision with rationale, alternatives, and consequences | | query_decisions | Searches the decision log by keyword or natural language query | | get_decision | Retrieves the full details of a specific decision by ID | | detect_conflicts | Analyzes a proposed decision against existing ones to find contradictions or overlaps | | log_todo | Records a TODO, known issue, or technical debt item with context and priority | | update_decision_status | Marks a decision as deprecated or superseded and links it to a replacement | | get_project_summary | Returns a high-level snapshot of active decisions, open TODOs, and technical direction |

Storage

All tools read and write from the same storage file. By default this is ~/.mcp/decision-log/decisions.json. Override it with the DECISION_LOG_PATH environment variable.

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