web-fetch

Web Fetch

Fetch one URL, prove it was allowed, extract the part the caller asked for, and return that slice by digest with the provenance needed to trust it later.

What this skill does

web-fetch retrieves a single public URL, extracts text, metadata, or links, and seals the result so a downstream step can cite the fetch without re-fetching. It checks the final host against the effective host policy before and after redirects, retrieves up to max_bytes, and returns the final URL, the HTTP status, a content_digest over the retrieved body, the extracted slice, and a provenance block recording when it ran, every redirect hop, and how many bytes it read. The body is referenced by digest; only the extracted slice is inlined.

This is the primitive an agent reaches for when it has already decided which page to read. The decision it makes easier is "can I read this page, and what did it actually say", with the answer backed by a digest instead of a remembered paraphrase. The calling agent decides which sources matter and synthesizes across them; web-fetch retrieves exactly one source. By default it may follow that source across any publicly routable host. Supply allowlist only when the operator needs to narrow the initial request and every redirect to named hosts.

The request path is native Runx code. Skills do not supply a JavaScript HTTP client: the runtime owns public-network enforcement, redirect admission, timeouts, retries, byte limits, response digests, and receipt-safe evidence.

When to use this skill

• An agent has chosen a specific page and needs its content bound to a content_digest so a later step can cite it without re-fetching.
• A research pass needs each source retrieved through one bounded public-network fetch with a complete redirect chain and byte count.
• A review must later prove what a page said at fetch time.
• A follow-on governed operation needs one source extracted as text, metadata, or links.

When not to use this skill