# Theo · Browser (Live-View Headless Browser)

> Theo Browser is a managed headless browser that an AI Worker can drive autonomously, with a live debugger surface so a human can watch (or take over) at any time. Branded as Theo Browser end-to-end. The upstream provider is never named on customer-facing surfaces.

Source of truth: https://hitheo.ai. Last updated: 2026-05-24.

## At a glance
- Managed session lifecycle. POST /api/v1/browser/sessions creates a session with a tracked liveViewUrl; DELETE releases the session and reconciles billing.
- Live view. GET /api/v1/browser/sessions/{id}/live returns a debugger iframe URL plus the open page list. Cached for 60 seconds; force-refresh available via ?force=1.
- Branded surface. The artifact uses providerId "theo-browser" and modelId "theo-1-browser". Tool descriptions, session payloads, and error messages never name the upstream provider.

## Tool surface (skills can call any of these)
- browser_start — open a session.
- browser_navigate — go to a URL. Forces a live-view refresh so the iframe picks up the new page within the 60s TTL.
- browser_act — perform a high-level action (click, type, select, scroll). Backed by an agentic act engine.
- browser_extract — pull structured data from the current page.
- browser_observe — read the current page's text + role tree.
- browser_screenshot — capture a screenshot, persisted to object storage with a Theo-branded artifact tag.
- browser_end — release the session.
- web_fetch — direct HTTP fetch with SSRF validation.
- web_search — web search via the research engine.

## In-turn action feed
Each browser_* call appends to an actions[] feed on the session artifact and re-emits via the agent loop's deduped collector, so the playground browser card + modal update in place as the AI Worker drives the session.

## Live view
The playground hosts a Theo-branded modal that embeds the debugger iframe alongside a real-time action feed. The CSP allows the upstream debugger origin so the frame loads. The branded modal is the only entry point a customer sees.

## Related machine-readable files
- https://hitheo.ai/llms.txt — full index of every Theo machine-readable file.
- https://hitheo.ai/llms-full.txt — long-form knowledge bundle (single fetch).
- https://hitheo.ai/humans.txt — team and open-source credits.
- https://hitheo.ai/lawyers.txt — trademark notice and legal contact.
- https://hitheo.ai/.well-known/security.txt — security disclosure contact.