fleet-memory/hindsight-docs/versioned_docs/version-0.4/developer/mcp-server.md

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MCP Server

Hindsight includes a built-in Model Context Protocol (MCP) server that allows AI assistants to store and retrieve memories directly.

Access

The MCP server is enabled by default and mounted at /mcp on the API server. Each memory bank has its own MCP endpoint:

http://localhost:8888/mcp/{bank_id}/

For example, to connect to the memory bank alice:

http://localhost:8888/mcp/alice/

To disable the MCP server, set the environment variable:

export HINDSIGHT_API_MCP_ENABLED=false

Authentication

By default, the MCP endpoint is open for local development. For production deployments, enable authentication with a Bearer token:

export HINDSIGHT_API_MCP_AUTH_TOKEN=your-secret-token

When authentication is enabled, all MCP requests must include a valid Authorization header:

Claude Desktop config (.claude_desktop_config.json):

{
  "mcpServers": {
    "hindsight": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-http-client", "http://localhost:8888/mcp/alice/"],
      "env": {
        "HTTP_HEADERS": "{\"Authorization\": \"Bearer your-secret-token\"}"
      }
    }
  }
}

Claude Code config:

claude mcp add --transport http hindsight http://localhost:8888/mcp/alice/ \
  --header "Authorization: Bearer your-secret-token"

Direct HTTP request:

curl -X POST http://localhost:8888/mcp/alice/ \
  -H "Authorization: Bearer your-secret-token" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc": "2.0", "method": "tools/list", "id": 1}'

If the token is missing or invalid, requests will receive a 401 Unauthorized response.

Per-Bank Endpoints

Unlike traditional MCP servers where tools require explicit identifiers, Hindsight uses per-bank endpoints. The bank_id is part of the URL path, so tools don't need to specify which bank to use—it's implicit from the connection.

This design:

• Simplifies tool usage — no need to pass bank_id with every call
• Enforces isolation — each MCP connection is scoped to a single bank
• Enables multi-tenant setups — connect different users to different endpoints

---

Available Tools

retain

Store information to long-term memory.

Parameter	Type	Required	Description
content	string	Yes	The fact or memory to store
context	string	No	Category for the memory (default: general)

Example:

{
  "name": "retain",
  "arguments": {
    "content": "User prefers Python over JavaScript for backend development",
    "context": "programming_preferences"
  }
}

When to use:

• User shares personal facts, preferences, or interests
• Important events or milestones are mentioned
• Decisions, opinions, or goals are stated
• Work context or project details are discussed

---

recall

Search memories to provide personalized responses.

Parameter	Type	Required	Description
query	string	Yes	Natural language search query
max_results	integer	No	Maximum results to return (default: 10)

Example:

{
  "name": "recall",
  "arguments": {
    "query": "What are the user's programming language preferences?"
  }
}

Response:

{
  "results": [
    {
      "id": "fact_abc123",
      "text": "User prefers Python over JavaScript for backend development",
      "type": "world",
      "context": "programming_preferences",
      "event_date": null
    }
  ]
}

When to use:

• Start of conversation to recall relevant context
• Before making recommendations
• When user asks about something they may have mentioned before
• To provide continuity across conversations

---

Integration with AI Assistants

The MCP server can be used with any MCP-compatible AI assistant.

Claude Desktop Configuration

To connect Claude Desktop to a specific memory bank:

{
  "mcpServers": {
    "hindsight-alice": {
      "url": "http://localhost:8888/mcp/alice/"
    }
  }
}

Each user can have their own MCP server configuration pointing to their personal memory bank.