Cosmos MCP Server

MCP server for the Polarity exocortex. Read and write your personal knowledge graph from any LLM client.

Remote serverstreamable-httpGo

What is the Cosmos MCP server?

Most AI and media services work still happens through a UI a human drives. Cosmos MCP server moves it into the conversation instead. MCP server for the Polarity exocortex. Read and write your personal knowledge graph from any LLM client.

The short version

Every AI you use is building its own private graph of you. Claude has one. ChatGPT has one. Cursor has one. None of them talk to each other, and none of them are yours.

Getting it running

Because this one is hosted, setup is mostly authentication — you point your client at the endpoint and approve access. Nothing runs on your machine, so there is no runtime to keep patched.

The tools it exposes

The server publishes 14 tools. What each one is for:

  • polarity_whoami — GET /api/polarity/whoami
  • polarity_export — POST /api/polarity/export
  • polarity_get_graph — GET /api/polarity
  • polarity_ask — POST /api/polarity/ask
  • polarity_observe — POST /api/polarity/observe
  • polarity_record_event — POST /api/polarity/observe (kind=event)
  • polarity_record_preference — POST /api/polarity/observe (kind=preference)
  • polarity_capture_turn — POST /api/polarity/capture-turn
  • polarity_dump — POST /api/polarity/dump
  • polarity_checkin — POST /api/polarity/checkin
  • polarity_declare — POST /api/polarity/declare
  • Source — How it connects

What it needs from you

Configuration is passed through the environment: COSMOS_TOKEN, COSMOS_URL, COSMOS_MCP_KEY, COSMOS_USER_ID, COSMOS_SYSTEM_KEY. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

Things to watch

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • With 14 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Cosmos.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

How it compares

Among the AI and media services options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Cosmos's toolset — polarity_whoami, polarity_export, polarity_get_graph and 11 more — is a fair guide to whether it matches your workflow. It is maintained by wearepolarity; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Cosmos's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Available tools

ToolWhat it does
polarity_whoamiGET /api/polarity/whoami
polarity_exportPOST /api/polarity/export
polarity_get_graphGET /api/polarity
polarity_askPOST /api/polarity/ask
polarity_observePOST /api/polarity/observe
polarity_record_eventPOST /api/polarity/observe (kind=event)
polarity_record_preferencePOST /api/polarity/observe (kind=preference)
polarity_capture_turnPOST /api/polarity/capture-turn
polarity_dumpPOST /api/polarity/dump
polarity_checkinPOST /api/polarity/checkin
polarity_declarePOST /api/polarity/declare
SourceHow it connects
iMessageLocal CLI: npx -y @polarity-lab/cosmos-mcp imessage sync. Mac only. Grant Terminal Full Disk Access first.
NotionOAuth at [cosmos.polarity-lab.com/connectors](https://cosmos.polarity-lab.com/connectors). Pick the pages and databases you want shared.

How to install the Cosmos MCP server

{
  "mcpServers": {
    "cosmos": {
      "command": "npx",
      "args": ["-y", "@polarity-lab/cosmos-mcp"],
      "env": {
        "COSMOS_TOKEN": "your-value",
        "COSMOS_URL": "your-value",
        "COSMOS_MCP_KEY": "your-value",
        "COSMOS_USER_ID": "your-value",
        "COSMOS_SYSTEM_KEY": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
COSMOS_TOKENCredential the server authenticates with.Yes
COSMOS_URLEndpoint or connection string the server talks to.Yes
COSMOS_MCP_KEYCredential the server authenticates with.Yes
COSMOS_USER_IDConfiguration value read at startup.Optional
COSMOS_SYSTEM_KEYCredential the server authenticates with.Yes

Example prompts to try

  • Use Cosmos to polarity whoami.
  • Use Cosmos to polarity export.
  • Use Cosmos to polarity get graph.

Frequently asked questions

It connects Cosmos to MCP-compatible AI assistants such as Claude and Cursor, exposing 14 tools (polarity_whoami, polarity_export, polarity_get_graph, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Cosmos directly.