Cosmos is a personal knowledge graph that every MCP-capable AI reads from and writes to. Claude, ChatGPT, Cursor, Codex, Zed, Obsidian, your iMessage, your browser. One graph, keyed to your account. The portable artifact is apolarity file. Self-hostable.
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Maker
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We built cosmos because every AI tool I use is keeping a private model of me, and none of them talk to each other. Claude has one. ChatGPT has one. Cursor has one. They each get a fraction of the picture and they never travel with me when I change tools.
Cosmos is the layer that lets them share. It is an MCP server, so any client that speaks Model Context Protocol can connect. The same key is valid in three different agents at the same time. Observations land in a graph keyed to your account, not to the client.
The hosted version is free. The portable artifact is a .polarity file you can take elsewhere if we ever ship something stupid.
Local connectors live in the CLI. The iMessage one reads your chat.db after you grant Full Disk Access, normalizes contact names through AddressBook, and lands real conversational turns as nodes in your graph. There is also a Notion sync, an Obsidian plugin, a Mac browser-history sync, and an Apple Calendar sync. All local-first.
Would love feedback, especially from people running heavy MCP setups.