# pi-web-search

Unified web search and fetch for Pi. The main model only ever sees two tools —
`web_search` and `web_fetch` — provider selection happens inside the extension.

- `web_search(query, max_results?, site?, published_after?, published_before?, depth?)`
  routes each query to Tavily, Exa, or Keenable using the session's current main
  model (`ctx.model` + `ctx.modelRegistry.complete`), guided by per-provider
  rules. Results include `details.provider` / `details.routedBy` for debugging.
- `web_fetch(urls, max_characters?)` always reads pages via Exa
  (`web_fetch_exa`), degrading silently to Keenable then Tavily.

## Providers (`clients/`)

Plain `fetch` calls — no MCP adapter, no upstream extension wrappers:

- `clients/tavily.ts` — `POST api.tavily.com/search|extract`, Bearer key.
  Requires a `tavily` credential.
- `clients/keenable.ts` — `api.keenable.ai`, keyless `/public` endpoints by
  default, a `keenable` credential raises rate limits. Adapted from
  `@keenable/pi-search`.
- `clients/exa.ts` — JSON-RPC over `mcp.exa.ai/mcp` (Streamable HTTP):
  `initialize` once, cache `mcp-session-id`, `tools/call` per request, re-init
  on session expiry. An `exa` credential is optional (`x-api-key` header).

Keys live in Pi's `auth.json` as one `api_key` credential per provider
(`tavily`, `exa`, `keenable`), read by `auth.ts` with upstream resolution
semantics — literal values, `$VAR`/`${VAR}` interpolation, and `!command`
indirection (e.g. `"!op read op://Vault/Tavily/key"`). `configure.sh search`
writes them (atomically, mode 600, preserving all other entries); process
environment variables are not read directly — use `"key": "$TAVILY_API_KEY"`
to indirect through env. `KEENABLE_API_URL` stays env-only, or can be stored
in the keenable credential's `env` map.

## Routing

`router.ts` asks the current model to answer with exactly one provider name,
given a prompt containing the per-provider strengths and the query's requested
filters. Decisions are cached per session (LRU, 32 entries). Failure paths are
deterministic: an unroutable answer or a dead provider falls back across the
remaining available providers — never a heuristic choice over the model.