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Version: MVP

Browser tool boundary

2 min readReferenceUpdated 2026-05-19

What you'll find here

The policy-controlled boundary that represents browser automation and tool execution as a sandbox backend — what the request records, required controls, and redaction.

Evaluates dispatch, doesn't drive the browser.

The helper in craik.runtime.browser_tool_boundary evaluates whether a caller has enough policy context to dispatch through a governed browser/tool backend. It does not drive a browser or invoke a tool.

What it records

BrowserToolRequest:

Backend id

Tool name

Capability name

Action reference

Policy envelope id

Capability grant id

Receipt id

Result metadata

Required controls

Sandbox backend

Kind browser_tool · isolation browser.

Declared backend capability

Matching the requested capability.

Policy envelope id

Capability grant id

Receipt id

Tool result metadata redaction

Requests missing any required control are denied before dispatch.

Result redaction

No raw payloads in receipts.

Tool result metadata must not persist raw page text, DOM, HTML, headers, cookies, screenshots, storage state, payloads, or secret-like fields. The boundary helper returns redacted metadata for both allowed and denied decisions.

What's next