MCP.Market

Cosmos MCP server

by teampolarity·io.github.teampolarity/cosmos-mcp·v0.7.1·3 stars
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Personal knowledge graph every MCP client reads from and writes to. Portable across agents.

B75/100grade B
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Safety scan
B75/100

full report

Adoption
Growing

3 stars222 downloads/wk

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If you have run it, two minutes of your experience saves the next person an afternoon.

Cosmos tools (11, 1 write)

write = sends, deletes, buys or posts

Read from the package source without running it. The installed server may list more.

  • polarity_ask

    Ask a natural-language question over the user's personal knowledge graph. Cosmos synthesizes an answer from relevant nodes and edges. Use this when the user wants context-aware reasoning rather than raw data. Returns answer text plus cited node/edge ids.

  • polarity_capture_turn

    This is how the user's cosmos graph learns from this conversation. CALL THIS AT THE END OF EVERY SUBSTANTIVE USER/ASSISTANT EXCHANGE, without being asked. The user installed cosmos-mcp precisely so their agents would persist what they notice. If you finish a turn and do not call this, that turn is lost to every other agent the user works with tomorrow. Cosmos runs its own extractor on the text and

  • polarity_checkin

    Record that the user checked in at a waypoint. Triggers co-presence detection against other users' recent check-ins.

  • polarity_declare

    Declare future presence at a waypoint. `chip` is the time-window enum: next_30, next_hour, tonight, tomorrow_night.

  • polarity_dumpwrite action

    Write a short message tied to a location waypoint into the user's graph. PolarityGPS-style. Use only when the user is explicitly recording a place-anchored thought.

  • polarity_export

    Export the user's full personal knowledge graph (nodes + edges + counts) as JSON in polarity/v1 format. Use this when the user asks for a snapshot of their exocortex, wants their data, or asks to download their .polarity file. Returns the full graph; can be large.

  • polarity_get_graph

    Read the user's graph view. `entity` selects which projection: 'user' (the user's self-graph), 'cosmos' (the cosmos entity's view of them), or 'polarity' (the dyadic synchronization between the two). Use 'user' for general questions about what the user thinks, does, or knows. Use 'polarity' when comparing the user's self-image against the system's observation.

  • polarity_observe

    Single-fact write into the user's personal cosmos graph. Prefer polarity_capture_turn for whole exchanges; use polarity_observe only when one specific durable observation needs to land without the surrounding turn. Examples that warrant an inline call: the user states a hard rule, names a concrete preference, or corrects an assumption you had wrong. Avoid logging ephemeral chat or your own reasoni

  • polarity_record_event

    Record a structured event in the user's graph. Convenience wrapper over polarity_observe with kind='event'. Use for things that happened at a point in time: a meeting, a shipped release, a flight, an incident.

  • polarity_record_preference

    Record a stated preference in the user's graph. Convenience wrapper over polarity_observe with kind='preference'. Use when the user expresses a like, dislike, opinion, or working-style rule that should persist across sessions.

  • polarity_whoami

    Returns the polarity user id and cosmos account info that this MCP key is bound to. Cheap connectivity test. Call this first if the user asks who you know them as.

Public scan report

scanner v0.1.9 · 2026-09-27 · same rubric, same numbers if you re-run it

no findings
  • Code scan53 source files scanned25/25
  • –Live reliabilityno gateway calls yet and no remote to proben/a
  • –Tool poisoningtools not inspected (local package is not executed); not countedn/a
  • Auth qualitystatic API keys via environment variables6/15
  • Maintenancelast push 33 days ago12/15
  • Maintainer identityregistry namespace matches repository owner6/10
Overall 75/100. Components that don't apply are left out of the denominator. Any critical finding is an F.RubricAppeal a findingJSON

How Cosmos compares

Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score
75/100
higher than 45% of 48,255 servers
Tools
11
the typical server has 7
Tools that change things
9%
typical: 0%. Fewer write tools means less an agent can break
GitHub stars
3
more than 80% of 28,688 servers
Downloads a week
222
more than 77% of 12,191 servers with a package

What its tools let an agent do: 10 read · 1 change

Install Cosmos in Claude Code, Cursor or VS Code

Runs npx -y @polarity-lab/cosmos-mcp on your machine. Read the scan report first; the gateway never runs local packages.

claude mcp add cosmos-mcp -- npx -y @polarity-lab/cosmos-mcp
Add to Cursor

What the publisher says

From the Cosmos repository's README, as published. We do not edit it. Read it on GitHub

cosmos-mcp

One exocortex. Every agent. MCP server for your Cosmos graph.

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.

Cosmos inverts that. Your knowledge graph lives in one place, and any MCP-capable client (Claude Code, Claude Desktop, Cursor, Codex, Zed, Continue) reads and writes to the same one. When an agent notices something durable about you, it lands in the graph. When you switch tools, the graph follows. The user, not the platform, owns the integration layer.

The thing you carry is a .polarity file. Yours.

One-line install

curl -fsSL https://mcp.polarity-lab.com/install.sh | sh

On macOS this installs the MCP server, registers cosmos-mcp://, wires Claude Desktop, Claude Code, Cursor, Codex, Zed, and Continue, then installs Cosmos Sync.app so iMessage, browser history, calendar, Claude Desktop transcripts, and shell history can sync in the background. On linux and windows it installs the MCP server path only.

If you want to inspect before changing anything:

curl -fsSL https://mcp.polarity-lab.com/install.sh -o install.sh
bash install.sh --dry-run
bash install.sh

Provisioning

There are two ways to get a pmk_… key onto your Mac.

Automatic. Sign in at cosmos.polarity-lab.com/connectors, tap "open in cosmos-mcp." The OS opens a one-shot handler that writes the key into your system keychain. You never see the raw key.

For that deep link to work, register the URL scheme once:

npx -y @polarity-lab/cosmos-mcp install-handler

This drops a tiny .app into ~/Library/Application Support/cosmos-mcp/ and registers cosmos-mcp:// with Launch Services. macOS-only.

Manual. If you already have a pmk_… key, or you do not want to install the handler:

npx -y @polarity-lab/cosmos-mcp provision pmk_xxx

The CLI validates the key against cosmos, then stores it in the macOS system keychain under service cosmos-mcp-key. Subsequent imessage sync, browser sync, calendar sync calls read from the keychain. No env var needed.

Confirm iMessage access.

npx -y @polarity-lab/cosmos-mcp imessage probe

Verifies Full Disk Access is granted and reports how many chats are visible. If you see an EACCES message, open System Settings, Privacy & Security, Full Disk Access, and add Terminal (or whichever app runs the CLI).

CI. Set COSMOSTOKEN=pmk… in env. It takes precedence over the keychain, so existing pipelines keep working untouched.

Manual MCP config

The installer handles this for common clients. If you want to wire a client by hand, point it at the package.

npx -y @polarity-lab/cosmos-mcp init

This opens your browser. Sign in at cosmos.polarity-lab.com, approve a per-user key, and the token lands at ~/.config/cosmos-mcp/token (0600). Then point any MCP client at it:

Shortened. The full README is on GitHub.

Nothing above is checked by us. What we check is on the safety report.

Cosmos: common questions

Is Cosmos MCP server safe?
Mostly: it is graded B (75/100). Read the Cosmos safety report
How do I install Cosmos?
It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
Does Cosmos need an API key?
Yes. The registry entry asks for COSMOS_TOKEN.
Is Cosmos maintained?
The last commit was 71 days ago (2026-08-25). The latest release is v0.7.1.
What can I use instead of Cosmos?
Servers from other publishers that do the same job: Codebase Memory MCP server and Neo4j Memory MCP server.
How does Cosmos compare with other MCP servers?
safety score 75/100 (higher than 45% of 48,255 servers); tools 11 (the typical server has 7); tools that change things 9% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.

Alternatives to Cosmos

Same job from other publishers: the closest match first, then the best rated.

  • Codebase Memory
    Codebase knowledge graph for AI agents — 162 languages, sub-ms queries, 99% fewer tokens.
    C
  • Neo4j Memory
    MCP Neo4j Knowledge Graph Memory Server
    A