Owl Browser (agent rendering)

Owl Browser is an AI-native browser. Instead of screenshots or raw HTML, it renders each page as OwlMark: a compact, handle-addressable text view of what is actually on screen. You observe the page, then act on handles. This is far cheaper than a screenshot and removes pixel-coordinate guessing.

Every call is POST $OWL_API_ENDPOINT/execute/\x3Ctool> with a JSON body and Authorization: Bearer $OWL_API_TOKEN. A reusable helper:

owl() { curl -s -X POST "$OWL_API_ENDPOINT/execute/$1" \
  -H "Authorization: Bearer $OWL_API_TOKEN" \
  -H "Content-Type: application/json" -d "$2"; }

The loop (do this, keep it short)

create_context(render_mode=agent) -> navigate(url) -> observe
   -> click/type(handle) -> observe -> ... -> close_context

• Call observe after navigating and after every action. It is the only way you see the page.
• Act using the handle tokens observe prints (e.g. l5, b12, x27). No CSS selectors, no pixel coordinates.
• observe blocks until the page is ready. Do not add a separate wait step.
• Never screenshot to read text or find elements. Screenshot only to judge visual design or layout.

Core tools

browser_create_context

Creates a session. Returns result.context_id (use it in every later call). Do NOT pass context_id in.

owl browser_create_context '{"render_mode":"agent"}'
# use "both" if you will also screenshot; "pixel" is the legacy human render

browser_navigate

owl browser_navigate '{"context_id":"ctx_...","url":"https://example.com"}'

Does NOT return the page. Call observe next.

browser_observe (your eyes)

Returns render (OwlMark text), handles (actionable elements), metadata, token_estimate.

owl browser_observe '{"context_id":"ctx_..."}'
owl browser_observe '{"context_id":"ctx_...","detail":"outline"}'   # headings-only map of a long page

Params: detail = min | normal (default) | full | outline; region = main/nav/header/footer or a handle; max_tokens = soft budget.

A handle in the render looks like: - link "Pricing" [#l5] or textbox "Email" [#x27 val=""]. Pass the token (l5, x27).

browser_click / browser_type (your hands)

Pass the handle token as selector (or handle). The response includes an effect: navigated, dom-changed, or no-effect. Trust it, then re-observe.

owl browser_click '{"context_id":"ctx_...","selector":"l5"}'
owl browser_type  '{"context_id":"ctx_...","selector":"x27","text":"[email protected]"}'

Also: browser_clear_input '{"context_id":"...","selector":"x27"}' before re-typing, and browser_press_key '{"context_id":"...","key":"Enter"}' to submit.

browser_screenshot (visual check only)

owl browser_screenshot '{"context_id":"ctx_..."}'

browser_close_context

owl browser_close_context '{"context_id":"ctx_..."}'

Drill-down tools (when observe collapsed something)

• browser_expand '{"context_id":"...","handle":"R1"}' re-serializes one collapsed region/template at higher detail.
• browser_read_node '{"context_id":"...","handle":"M1"}' returns the full text of a single node (e.g. an article body).

Edge cases and recovery

Check metadata.status on every observe:

• ready — act on it.
• pending — the page has not rendered its content yet (a lazy client-rendered shell). The envelope has reason and retry_after_ms; re-observe after that delay. Do NOT treat a pending render as an empty page.
• incomplete — chrome rendered but main content did not; re-observe once, then use vision.

metadata.dropped_surfaces tells you what text could not capture:

• canvas / webgl / image:N — a visual surface. Use render_mode:"both" + browser_screenshot + your own vision.
• sparse_main / shell_unhydrated / main_content_unrendered — content is late or withheld; re-observe, then vision if still empty.
• first_tree_timeout — slow or bot-blocked; read it with a screenshot.

Other cases:

• Handles are per-document. After any navigation (a click whose effect is navigated, or a browser_navigate), re-observe to get fresh handles. Acting on a stale handle returns STALE_HANDLE; when you see that, re-observe.
• Same-page anchors scroll, they do not navigate. Clicking an href="#section" link returns effect: "scrolled" and moves the viewport. Expected, not a failure.
• Rare click-nav crash: on a few slow sites, a click that triggers a cross-document navigation can crash and auto-respawn the browser (~1s). If a context is lost right after such a click, recreate the context and browser_navigate directly to the destination URL instead of clicking.
• PDF / embedded plugins: read the content with a screenshot (render_mode:"both"); in-page plugin controls may not be actionable handles.

Do and do not

• DO observe before acting and re-observe after every action.
• DO act on the exact handle tokens observe printed.
• DO read the effect of a click/type before assuming it worked.
• DO use detail:"outline" on long reference pages, then expand/read_node the part you need.
• DO NOT screenshot to read a page or find elements.
• DO NOT guess pixel coordinates. Owl gives you handles so you never have to.
• DO NOT pass context_id to create_context; it is returned to you.

Minimal example: search and open a result

CTX=$(owl browser_create_context '{"render_mode":"agent"}' | jq -r .result.context_id)
owl browser_navigate "$(printf '{"context_id":"%s","url":"https://duckduckgo.com"}' "$CTX")"
owl browser_observe  "{\"context_id\":\"$CTX\"}"                 # find the search box, e.g. x4
owl browser_type     "{\"context_id\":\"$CTX\",\"selector\":\"x4\",\"text\":\"owl browser olib ai\"}"
owl browser_press_key "{\"context_id\":\"$CTX\",\"key\":\"Enter\"}"
owl browser_observe  "{\"context_id\":\"$CTX\"}"                 # results appear, pick a link, e.g. l31
owl browser_click    "{\"context_id\":\"$CTX\",\"selector\":\"l31\"}"
owl browser_observe  "{\"context_id\":\"$CTX\"}"                 # read the opened page
owl browser_close_context "{\"context_id\":\"$CTX\"}"

Notes

• Over MCP, the Owl MCP server exposes this same loop and defaults to render_mode=agent; the toolset is profile-scoped via OWL_MCP_PROFILE (agent, automation, webdev, full).
• The full machine-readable tool reference is served at GET $OWL_API_ENDPOINT/agent-skills.md.