MCP in Cursor

Cursor is an AI-powered IDE based on VS Code. With Synapse MCP, Cursor gains persistent memory across sessions — it remembers your project decisions, codebase patterns, and past debugging sessions.

Prerequisites

• Cursor IDE installed (https://cursor.com)
• Node.js 18+
• Your Synapse Mind Key

Setup

Step 1: Open Cursor Settings

In Cursor:

1. Open Settings (Cmd+, on macOS, Ctrl+, on Windows/Linux)
2. Search for "MCP" or navigate to Cursor Settings → MCP Servers

Step 2: Add Synapse MCP Server

Click "Add MCP Server" and configure:

Field	Value
Name	synapse
Type	stdio
Command	npx -y synapse-mcp-api@latest
Env	SYNAPSE_MIND_KEY=mk_YOUR_KEY, SYNAPSE_URL=https://synapse.schaefer.zone

Step 3: Edit config.json directly (alternative)

Cursor stores MCP config in ~/.cursor/config.json:

{
  "mcpServers": {
    "synapse": {
      "command": "npx",
      "args": ["-y", "synapse-mcp-api@latest"],
      "env": {
        "SYNAPSE_MIND_KEY": "mk_YOUR_MIND_KEY_HERE",
        "SYNAPSE_URL": "https://synapse.schaefer.zone"
      }
    }
  }
}

Step 4: Restart Cursor

Fully restart Cursor (Cmd+Q and reopen on macOS).

Verify It Works

In Cursor's chat panel (Cmd+L):

recall all my memories

Cursor should call memory_recall and respond with your stored memories.

Common Patterns

Project onboarding

When opening a new project:

recalling project context — what do I know about this codebase?

Cursor calls memory_recall and continues work where you left off.

Architecture decisions

store this decision: "Using Fastify instead of Express for this project
because of schema validation. Date: 2026-06-27."

Cursor stores it as a project memory with high priority.

Debugging history

what bugs have I hit in this codebase?

Cursor searches for mistake memories and reminds you of past fixes.

Cross-session code patterns

search memories: "authentication pattern"

Cursor finds memories about auth implementations you've done before.

Troubleshooting

MCP server not connecting

1. Verify Node.js: node --version (≥ 18)
2. Test MCP server: npx -y synapse-mcp-api@latest (should start without errors)
3. Check Cursor's MCP logs (View → Output → MCP)
4. Restart Cursor fully

Tools not appearing

• Check ~/.cursor/config.json is valid JSON
• Verify SYNAPSE_MIND_KEY env var is set
• Check Cursor version supports MCP (≥ 0.42)

Mind Key invalid

# Test your Mind Key directly
curl -H "Authorization: Bearer mk_YOUR_KEY" \
     https://synapse.schaefer.zone/memory/recall

Next Steps

• Claude Desktop Setup
• Continue.dev Setup
• Persistent LLM Agent Guide