zu-tools 0.4.0

Zu built-in tools: web_search, http_fetch, html_parse, pdf_extract, render_dom, browser

zu-tools

Tools — the Tool port: actions the model may take. A tool declares its tier (the escalation ladder), its JSON schema, a prompt_fragment, and its capability envelope (capabilities + egress) so its blast radius is visible in its own code and the gate can bound it.

Registered plugins (zu.tools)

Name	Class	Tier	Envelope
http_fetch	HttpFetch	1	CAP_NET, open egress — a general web fetcher with a host-level SSRF guard (net.check_url).
html_parse	HtmlParse	1	none — pure CPU on HTML it is handed (least privilege).
render_dom	RenderDom	2	CAP_NET + CAP_SANDBOX, open egress — renders a URL in a headless browser inside a SandboxBackend (unlocked only after a detector escalates off tier 1).

The tier ladder

http_fetch and html_parse are tier 1 (cheap, offered from the start). render_dom is tier 2 — the escalation target when a JavaScript page defeats tier 1. The loop only offers tools at or below the current tier; a detector ESCALATE climbs the ladder. The browser runs in a sandbox behind a seam tests can freeze (a saved rendered page), so the escalation arc is proven offline.

Extend

Implement the Tool shape (see AGENTS.md → Recipe: add a tool), declare a minimal capabilities/egress, register under zu.tools, and add a deterministic test (use an httpx.MockTransport to fixture the network).

Tests

uv run pytest packages/zu-tools — offline; the network is fixtured.