Cosmos Mcp

io.github.teampolarityPublished by GitHub account teampolarityv0.7.1Updated Oct 24, 2026

Personal knowledge graph every MCP client reads from and writes to. Portable across agents.

VerifiedSTDIODesktop onlyProductivity & WorkflowFiles & StorageKnowledge & Memory

Overview

AI-generated overview

Gives an assistant read and write access to a personal Cosmos knowledge graph, so observations, events and preferences persist across MCP clients.

What you can do
Exposes eleven tools: four read tools (whoami, export, get_graph, ask) and seven write tools (observe, record_event, record_preference, capture_turn, reconstruct_hours, dump, checkin, declare) that post observations, events, preferences, location dumps and check-ins to the Cosmos graph. A CLI adds local sync subcommands for iMessage, Claude Code transcripts, shell history, browser and calendar, plus a macOS background daemon. The graph is stored in the user's Cosmos account and is meant to be portable across clients.
When to use it
Use it when you want one shared memory layer that several MCP clients (Claude Code, Claude Desktop, Cursor, Codex, Zed, Continue) read from and write to, instead of each tool keeping its own private context. It also suits users who want local messages, notes or shell history folded into that graph. It is less useful if you only need a single client's session memory.
Requirements
Local Node.js process run via npx from the npm package @polarity-lab/cosmos-mcp over stdio. Needs a pmk_ key from the Cosmos connectors page, supplied as COSMOS_TOKEN or stored in the macOS keychain; optional COSMOS_URL, COSMOS_MCP_KEY, COSMOS_USER_ID and COSMOS_SYSTEM_KEY variables. Network access to cosmos.polarity-lab.com. macOS-only features (keychain, deep-link handler, background daemon, iMessage and calendar sync) require Full Disk Access.
Before you install
The server asks for a pmk_ key (COSMOS_TOKEN or the keychain entry) and can read sensitive local data: iMessage chat.db, calendar, browser history, shell history and Claude Code transcripts, which are sent to the Cosmos service. macOS sync needs Full Disk Access for Terminal or the Cosmos Sync.app bundle. The one-line install script registers URL schemes, rewrites client configs and installs a background LaunchAgent; inspect it with --dry-run first. Write tools add data to the graph, and the key

Installation

In SourceWeft

  1. Open Cosmos Mcp in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

[Polarity]

cosmos-mcp

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

[npm] [license] [site] [glama]

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

bash
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:

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

bash
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:

bash
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.

bash
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 COSMOS_TOKEN=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.

bash
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:

json
{  "mcpServers": {    "cosmos": {      "command": "npx",      "args": ["-y", "@polarity-lab/cosmos-mcp"]    }  }}

That config drops into ~/Library/Application Support/Claude/claude_desktop_config.json for Claude Desktop, your .cursor/mcp.json for Cursor, the equivalent for whichever client.

What you get

Eleven tools, four read, seven write.

Read

ToolCallsWhat it returns
polarity_whoamiGET /api/polarity/whoamiBound user + scopes. Cheap probe.
polarity_exportPOST /api/polarity/exportFull personal graph as polarity/v1 JSON.
polarity_get_graphGET /api/polarityGraph view, scoped by entity (user, cosmos, polarity).
polarity_askPOST /api/polarity/askNL question synthesized over the graph.

Write

ToolCallsWhat it does
polarity_observePOST /api/polarity/observeFreeform observation. Cosmos extracts.
polarity_record_eventPOST /api/polarity/observe (kind=event)Something happened at a point in time.
polarity_record_preferencePOST /api/polarity/observe (kind=preference)A like, dislike, working-style rule.
polarity_capture_turnPOST /api/polarity/capture-turnHand a whole user/assistant exchange to cosmos. Pulls every durable observation in one call. Prefer over multiple polarity_observe calls.
polarity_reconstruct_hoursPOST /api/polarity/reconstruct-hoursPersist life-hour receipts onto the skill-map sky (per user only). Use from Cursor/Cosmos IDE after substantive work.
polarity_dumpPOST /api/polarity/dumpLocation-anchored short message.
polarity_checkinPOST /api/polarity/checkinCheck-in at a waypoint. Triggers co-presence detection.
polarity_declarePOST /api/polarity/declareDeclare future presence at a waypoint.

Sources

The MCP server is one way to write to the graph. Cosmos accepts source pages from anywhere you keep notes, and the MCP read tools see all of it through the same view.

SourceHow it connectsWhat lands
iMessageLocal CLI: npx -y @polarity-lab/cosmos-mcp imessage sync. Mac only. Grant Terminal Full Disk Access first.Conversational turns from chat.db, with text content. People appear as person nodes in your graph, sized by conversation weight, named via your local AddressBook, dated by your real message timestamps.
Claude DesktopLocal CLI: npx -y @polarity-lab/cosmos-mcp claude-desktop sync. Reads Claude Code session transcripts at ~/.claude/projects/.Every Claude Code session becomes a thread node; user and assistant turns land in conversation_turns with full text. Tool-use plumbing is stripped client-side.
Shell historyLocal CLI: npx -y @polarity-lab/cosmos-mcp shell-history sync. Reads ~/.zsh_history (falls back to bash/fish) with a byte-offset watermark.Each sync window lands as one source_page keyed by shell-history:<sync-iso>, body = newline-joined commands. Trivial commands (ls, cd .., single chars) and consecutive duplicates are filtered client-side.
NotionOAuth at cosmos.polarity-lab.com/connectors. Pick the pages and databases you want shared.Each Notion page becomes a source_page node, keyed by Notion id, kept fresh by a daily sync.
ObsidianCommunity plugin: polarity-lab/obsidian-cosmos. Paste your pmk_ key, point at your vault.Each note becomes a source_page node keyed by vault-relative path. Tags and wikilinks resolve into edges.
MCP clientsThis package.Observations, events, preferences, location dumps, check-ins, declarations.
Direct APIPOST /api/polarity/observe with your key.Anything you can express as an observation.

Unchanged pages are skipped server-side, so re-syncing a quiet vault or stable Notion workspace costs almost nothing. The iMessage sync is incremental too, watermarked on the last successful run, so re-running it is a no-op until new messages arrive.

iMessage sync

cosmos-mcp ships an imessage subcommand that reads your local Messages database and lands every conversation in your graph.

bash
# default: incremental sync, 90-day window on first runnpx -y @polarity-lab/cosmos-mcp imessage sync
# re-sync the original 90-day window regardless of watermarknpx -y @polarity-lab/cosmos-mcp imessage sync --backfill
# pull everything since a specific datenpx -y @polarity-lab/cosmos-mcp imessage sync --since 2024-01-01
# check what the last run didnpx -y @polarity-lab/cosmos-mcp imessage status

A three-rule slop filter (no-reply senders, short-code numbers, low-volume contacts) keeps the graph clean. Your AddressBook resolves phone numbers and emails into real contact names. The reading is local to your Mac; only the extracted, normalized turns go into your cosmos graph, which is your account.

Claude Desktop sync

cosmos-mcp ships a claude-desktop subcommand that watches Claude Code session transcripts and lands each turn in your graph. The desktop chat surface itself stores conversations server-side, so the live, watchable on-disk source is ~/.claude/projects/<encoded-cwd>/<session-id>.jsonl.

bash
# default: incremental, watermarked per sessionnpx -y @polarity-lab/cosmos-mcp claude-desktop sync
# limit to recent activitynpx -y @polarity-lab/cosmos-mcp claude-desktop sync --since 2026-05-01
# scan and report without shippingnpx -y @polarity-lab/cosmos-mcp claude-desktop sync --dry-run
# see what the last run didnpx -y @polarity-lab/cosmos-mcp claude-desktop status

Tool-use blocks, hook plumbing, and sub-agent (sidechain) turns are stripped client-side; only the visible text the user and the assistant exchanged is shipped. Each session id becomes its own thread node, keyed by (user_id, "claude-desktop", session_id).

Background sync (macOS)

cosmos-mcp daemon install drops a LaunchAgent that ticks every four hours and runs the browser, iMessage, calendar, claude-desktop, and shell-history syncs back-to-back. The agent fires a signed, notarized Cosmos Sync.app bundle that ships inside the npm package and gets copied into ~/Applications/Cosmos Sync.app at install time.

bash
npx -y @polarity-lab/cosmos-mcp daemon install

After install, grant the bundle Full Disk Access once:

  1. open System Settings → Privacy & Security → Full Disk Access
  2. click +, then drag ~/Applications/Cosmos Sync.app into the list
  3. make sure the checkbox next to it is on
  4. run cosmos-mcp daemon kick to fire a tick now

Browser sync works without that step. iMessage and Calendar need it because they read TCC-protected SQLite databases on the user side. cosmos-mcp daemon status reports the signing team id, the plist + runner paths, and whether launchd has the agent loaded. cosmos-mcp daemon uninstall removes the plist, runner, and ~/Applications/Cosmos Sync.app.

Configuration

Env varDefaultWhen you set it
COSMOS_URLhttps://cosmos.polarity-lab.comOverride the cosmos API endpoint.
COSMOS_TOKEN(from keychain)pmk_... per-user key for CLI subcommands. Takes precedence over the macOS keychain entry. Set this in CI.
COSMOS_MCP_KEY(from token file)pmk_... per-user key. Honored for back-compat.
COSMOS_USER_ID(from token file)Polarity user id.
COSMOS_SYSTEM_KEY(unset)Single-tenant mode. Sends X-System-Key instead of X-MCP-Key. Requires COSMOS_USER_ID. For internal testing before per-user keys are deployed.

The pitch in three lines

Your AI tools each know fragments of you. They are not allowed to share. Cosmos is the layer that lets them. You hold the key. The graph is portable. When you leave, you take the understanding with you.

License

MIT.

Source: README.md at commit 3d04c64

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.7.1LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts