Project Brain MCP

Engineering memory for Claude Code — prevents re-investigating solved problems and repeating rejected architectural decisions across sessions and projects.

What it does

• Prevent re-investigating: Answered questions are recorded as findings. Future sessions skip re-investigation.

• Prevent repeating rejected architectures: validate_plan checks your proposal against past decisions and mistakes before you proceed.

• Cross-project learning: Decisions from other projects appear as soft references, not hard blocks.

• Persistent memory: Survives across sessions, stored in ~/.project-brain/memory.json.

Related MCP server: Cortex

Installation

pip install git+https://github.com/pym2282/project-brain-mcp
claude mcp add project-brain project-brain-mcp --scope user

Restart Claude Code. The MCP server is now active in all your projects.

Uninstall

pip uninstall project-brain-mcp
claude mcp remove project-brain --scope user

Memory location

Memory is stored at ~/.project-brain/memory.json — shared across all projects, never committed to any repo.

To use a custom path:

export PROJECT_BRAIN_MEMORY_PATH=/path/to/memory.json

Tools

How validate_plan works

validate_plan("use sqlite for storage", current_project="my-app")
→ conflicts:  [entries from "my-app" that match — must resolve]
→ references: [entries from other projects — consider as context]

Same project matches are hard conflicts. Other project matches are soft references.