pi-browser-search

A pi extension that adds browser_search, browser_open, browser_act, and browser_read tools backed by a real Playwright Chromium browser.

Static fetching can't handle JavaScript-rendered pages, SPAs, cookie walls, or lazy-loaded content. This extension drives an actual browser instead, while enforcing the same defense-in-depth as pi-safe-search: prompt-injection sanitization on every result, and SSRF protection enforced at the network layer on every request the browser makes — not just the ones the model asked for.

Install

From npm:

pi install npm:pi-browser-search

Or from git:

pi install git:github.com/sebaxzero/pi-browser-search.git

Add -l to either form to install project-locally (adds to .pi/settings.json only).

No manual setup: the playwright npm dependency installs automatically with the package, and the Chromium binary (~150 MB) downloads once on the first browser launch. To pre-download it instead, run npx playwright install chromium in the install directory.

How it works

Sanitization pipeline (runs on every result)

Shared with pi-safe-search. Every piece of page content passes through this pipeline before reaching the LLM:

1. Unicode normalization — NFKC normalization plus a homoglyph map folds lookalike characters to ASCII
2. Zero-width character removal — strips invisible characters used to hide instructions
3. Control character stripping — removes everything below space except \t, \n, \r
4. HTML entity decode → re-strip — decodes <script> then strips the resulting tags
5. URL decode — catches percent-encoded payloads
6. Base64 blob redaction — replaces suspicious base64 blobs with [BASE64_ENCODED_DATA]
7. Injection pattern redaction — override directives, role hijacking, system prompt extraction, mode switching, and more
8. Random-delimiter wrapping — content is fenced with a random token so the LLM treats everything inside as data, never instructions

A second sanitization pass runs on every tool result via the tool_result hook, catching anything that slips through.

SSRF protection at the network layer

Unlike a plain fetch-based tool, a rendered page can issue requests the model never asked for — redirects, iframes, XHR calls, subresources. A context.route("**/*") interceptor checks every one of them against:

• Non-http(s) schemes (file://, ftp://, etc.)
• Dangerous ports: 21, 22, 25, 53, 3306, 5432, 6379, and more
• RFC-1918, loopback, link-local, and reserved IP ranges (DNS-resolved, 60s cache)

browser_open additionally validates the URL up front with descriptive errors before navigation starts.

Browsing model

The extension keeps one lazy-launched browser/context and one "current page." browser_open navigates and extracts text and links; browser_act clicks, types, presses keys, scrolls, or waits on that page; browser_read pages through the last extracted content by character offset without refetching. A click that opens a new tab switches to it, and dialogs are auto-dismissed.

browser_search deliberately uses DuckDuckGo's static HTML endpoint over plain fetch — DDG bot-walls headless Chromium — so the browser is spent only on what needs it: rendering and interacting with pages.

Tools

browser_search — Searches DuckDuckGo and returns titles, URLs, and snippets.

Parameters:

• query (required) — search query
• max_results (optional) — number of results, default 5, max 10

browser_open — Navigates to a URL and returns rendered text plus a link list.

Parameters:

• url (required) — must be http or https

browser_act — Interacts with the currently open page: click, type, press, scroll, or wait_for.

browser_read — Pages through the last snapshot's extracted text by character offset, no refetch.

Configuration

Persistent configuration lives in extensions/browser-search.json (auto-created on first load with defaults). You can ask the agent to edit it directly:

{
  "MAX_RESULTS": 5,
  "MAX_CHARS": 8000,
  "MAX_LINKS": 25,
  "NAV_TIMEOUT_MS": 30000,
  "HEADLESS": true,
  "BLOCK_MEDIA": true
}

Key	Default	Description
MAX_RESULTS	5	Default number of search results returned by browser_search (1–10)
MAX_CHARS	8000	Page text returned per browser_read chunk
MAX_LINKS	25	Links listed per page
NAV_TIMEOUT_MS	30000	Navigation timeout in milliseconds
HEADLESS	true	Set false to watch the browser window
BLOCK_MEDIA	true	Skip loading images/media/fonts

Changing HEADLESS or BLOCK_MEDIA or NAV_TIMEOUT_MS closes the current browser so the next call relaunches with the new options.

Changes to the JSON take effect on the next session. For live tuning within a session, use the command below.

Command

/browser-search                 — show current status and config
/browser-search set KEY=VAL     — override config for the current session only
/browser-search reset           — close the browser

Compatibility

Shares its sanitization and SSRF model with pi-safe-search — install both if you want cheap static fetch for most pages and a real browser reserved for JS-heavy ones.

Dependencies

playwright (^1.53.0) — installed automatically with the package, whether via pi install npm: or a git-based install. The Chromium binary is downloaded separately on first browser launch (see Install above).

Tests

node --test test.mjs

17 tests covering IP range checks, URL validation, DuckDuckGo redirect unwrapping, and a sanitization smoke test. Pure logic lives in net.ts and sanitize.ts (no Playwright import), so the suite runs without a browser. CI runs it on every push and pull request.

Releasing

Bump version in package.json, commit, tag vX.Y.Z, and push the tag — the publish workflow runs the tests and publishes to npm.

License

MIT

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Built with Claude.