Browser Open

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

No annotations are provided, so the description must carry the full behavioral burden. It mentions 'session' naming the attachment, but does not disclose important behaviors such as whether the tool waits for page load (wait parameter), timeout behavior, or side effects like changing the active session. It also doesn't explain what happens when both url and target_id are provided. The description is too sparse for a tool with no annotations.

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, dense sentence that front-loads the core action ('Open a URL') and then adds the attachment mode. It is efficient and free of filler, though it packs a lot of information into one sentence, which could be slightly clearer with separation. Overall, it is concise and well-structured.

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?

With 7 parameters and no annotations, the description is incomplete. It does not explain the return value (though an output schema exists), nor does it clarify the roles of wait, timeout, or device. It does not describe how to handle errors or whether the tool blocks until the page loads. For a tool with such complexity, the description falls short of providing sufficient context for correct invocation.

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?

Schema description coverage is 0%, meaning the description is the only source of parameter meaning. It explains target_id, app, and session, but ignores url, wait, device, and timeout. The description provides partial clarity for 3 of 7 parameters, leaving the rest undefined. It does not compensate for the complete lack of schema descriptions.

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 tool's primary function: 'Open a URL in the on-device browser' and its secondary attachment mode. It specifies the resource (URL/browser) and the verb (open/attach), and distinguishes from siblings like browser_tabs and browser_read by mentioning target_id and app for WebView. The purpose is unambiguous.

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 explains when to use the tool: to open a new URL or attach to an existing page (via target_id or app). It gives a specific source for target_id (browser_tabs) and hints at the app parameter for WebView. However, it does not explicitly state when not to use this tool or compare it to other browser_* tools, but the usage context is clear enough for an agent to decide when to invoke it.

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