Foxhole – Firefox sidebar where Claude remembers how sites work

I built this because every time I asked Claude to help me interact with a website, it would rediscover the same things from scratch — is this a React SPA? Does it have an API? Which selectors work?

  Foxhole is a Firefox sidebar extension where Claude learns and remembers how each site works across sessions.
  It saves site profiles (UI-only vs API-driven), working selectors, endpoints, and workflows. Next visit, it
  reads those specs before doing anything.

  Key things it does differently:

  - Site profiles: knows whether to click buttons or call APIs
  - Spec staleness: flags old knowledge, Claude can delete broken specs
  - Not QA automation: asks the user to handle age gates, logins, CAPTCHAs instead of flailing
  - Prompt injection defense: sanitizes page content before Claude sees it
  - Context compression: strips screenshots and raw payloads from old turns, keeps semantic summaries

  Firefox-only (Manifest V2), no build step, raw JS. Uses your own Anthropic API key.