MCP Configuration for BrainLayer

One MCP server: BrainBar on /tmp/brainbar.sock. Agents connect with the shipped reconnecting brainlayer-mcp-stdio-bridge (no Homebrew socat required; GUI hosts like Zed/VS Code/Claude Desktop do not have /opt/homebrew/bin on PATH). socat STDIO UNIX-CONNECT:/tmp/brainbar.sock is the documented manual alternative. The Python brainlayer-mcp entrypoint is deleted — do not wire it.

Prerequisites:

BrainBar is running and owns /tmp/brainbar.sock.
brainlayer-mcp-stdio-bridge is on PATH (installed with the BrainLayer package).

Add this to Claude, Codex, Cursor, or Gemini MCP settings under mcpServers:

{
  "mcpServers": {
    "brainlayer": {
      "command": "brainlayer-mcp-stdio-bridge"
    }
  }
}

Manual alternative when you already have socat on PATH (Homebrew: /opt/homebrew/bin/socat):

{
  "mcpServers": {
    "brainlayer": {
      "command": "socat",
      "args": ["STDIO", "UNIX-CONNECT:/tmp/brainbar.sock"]
    }
  }
}

brainlayer setup --migrate-mcp rewrites owned configs still pointing at the deleted brainlayer-mcp entrypoint to the socat socket form (backing up each file first). It matches by server name and leaves entries that already use socat or brainlayer-mcp-stdio-bridge untouched — so wiring the bridge yourself, as recommended above, is not undone by setup.

Testing the MCP Server

Confirm BrainBar owns the MCP socket:

test -S /tmp/brainbar.sock
(printf '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"smoke","version":"0"}}}\n'; sleep 1) \
  | socat STDIO UNIX-CONNECT:/tmp/brainbar.sock \
  | tee /tmp/brainlayer-mcp-smoke.out
grep '"id":1' /tmp/brainlayer-mcp-smoke.out

In Claude Code, the core palette should appear — 5 tools, not all 17:
brain_search - Search memory by topic
brain_store - Persist decisions, corrections, learnings
brain_recall - Session context and stats
brain_expand - Open one search result in full, with surrounding chunks
expand_palette - Expose the other 13 tools for this session

Calling expand_palette (or starting the server with BRAINLAYER_MCP_PROFILE=full) returns all 17 with their full descriptions. A gated tool called before expanding returns an error saying so.