Cosmos MCP runs on your own machine — the client starts it, so there is no endpoint to ping. 129 installs a week from npm. Last commit 26 Aug 2026.
Personal knowledge graph every MCP client reads from and writes to. Portable across agents.
What the code does
We read the source, 21 h ago · rules 3dff92dd89df
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
"\(home)/Library/LaunchAgents/com.polaritylab.cosmos-mcp.sync.plist"
postinstall: npm rebuild better-sqlite3 2>/dev/null || true
spawnSync(rebuildCmd, ["rebuild", "better-sqlite3"], {
let process = Process()
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
Connect this server
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add cosmos-mcp -- npx -y @polarity-lab/cosmos-mcp{
"mcpServers": {
"cosmos-mcp": {
"args": [
"-y",
"@polarity-lab/cosmos-mcp"
],
"command": "npx"
}
}
}[mcp_servers.cosmos-mcp]
command = "npx"
args = ["-y", "@polarity-lab/cosmos-mcp"]{
"mcpServers": {
"cosmos-mcp": {
"args": [
"-y",
"@polarity-lab/cosmos-mcp"
],
"command": "npx"
}
}
}{
"mcpServers": {
"cosmos-mcp": {
"args": [
"-y",
"@polarity-lab/cosmos-mcp"
],
"command": "npx"
}
}
}This one needs environment variables set before it will start:
COSMOS_TOKEN (pmk_ key from https://cosmos.polarity-lab.com/connectors. Optional on macOS once the system keychain is provisioned via `npx -y @polarity-lab/cosmos-mcp provision pmk_...`.).
The author declared them in the registry entry; get the values from the project itself.
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Cosmos MCP — questions
Answers built from our own checks of this server.