cosmos by polarity lab

About

cosmos by polarity lab is the browser-history connector for cosmos, the
exocortex at cosmos.polarity-lab.com. it walks your chrome.history.search,
filters out navigational noise client-side, and ships the pages that
actually meant something into your personal knowledge graph.

what gets sent
- url, title, hostname, last-visit timestamp, visit count, and the
  static string "web" as source. that's the entire payload per page.
- no page bodies, no cookies, no form data, no request headers, no
  tracking pixels. the network call carries exactly the fields above
  and nothing else.

what gets filtered (locally, before the network call)
- navigational noise, search-result URLs, untitled tabs, your own
  domains. filter rules live in the open at shared/filter-rules.json
  in the source repo. nothing leaves your machine without passing
  through this.

how it runs
- hourly background sync via chrome.alarms. installs with a 90-day
  lookback on first sync so the graph starts with the last quarter
  of your real reading, not a year-zero blank slate. subsequent
  syncs are incremental and idempotent.

how to use it
1. open chrome://extensions and pin the cosmos icon.
2. go to cosmos.polarity-lab.com/connectors, mint an MCP key.
3. paste the key into the extension's options page. that's it.

the cosmos MCP key lives in chrome.storage.local and is sent only as
the X-MCP-Key header to cosmos.polarity-lab.com. no other endpoint is
contacted. no analytics, no telemetry.

permissions justification
- history: read the browser history this extension is named after.
  the whole product is "your reading becomes your graph."
- storage: hold the MCP key and the last-sync watermark.
- alarms: schedule the hourly background sync.
- host permission to cosmos.polarity-lab.com only.

source code at github.com/teampolarity/cosmos-browser-extension.