browser.open_url

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the basic action and mentions 'allowlisted', which hints at a restriction, but it does not disclose what happens on failure, whether the session navigates away, or what 'wait_until' and 'timeout_ms' imply about behavior. This leaves significant ambiguity about tool side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence, highly concise with no wasted words. It is front-loaded with the action and resource, making it easy to parse. However, its brevity means it lacks depth, though that is more of a completeness issue than a conciseness issue.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has no output schema, no annotations, and 4 parameters with zero schema descriptions, the description is far from complete. It does not explain the return value, error handling, or the meaning of the timeout and wait conditions. This is inadequate for a tool that navigates a browser session.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage, so the description must explain parameter meanings. It only implicitly refers to 'URL' and 'browser session', but provides no guidance on 'timeout_ms' or 'wait_until', which are key parameters. The description adds negligible value beyond the raw parameter names.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Opens'), the target ('an allowlisted URL'), and the context ('in the browser session'), which specifically identifies the tool's purpose. It distinguishes from sibling tools like browser.start_session (which starts a session) and browser.inspect_page (which inspects), as opening a URL is a distinct action.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool, prerequisites (e.g., an active session), or alternatives. It does not mention any exclusions or conditions under which another tool should be used instead, leaving the agent without decision-making support.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.