browser_frame_bbox

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

No annotations are present, so the description carries the full burden. It adds useful context such as 'page coordinates' and the return tuple, but does not disclose whether the operation is read-only, what happens if the frame selector is invalid, or any potential side effects. This is a minimal but not misleading disclosure.

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 two short sentences with no fluff. The first sentence states the core function, and the second provides a concrete usage example. Every word earns its place.

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?

For a simple one-parameter read-only tool with no output schema, the description covers the essential return shape and suggests a primary use case. It does not explicitly mention 'iframe' in the description, but the schema does. Overall, it is reasonably complete for the tool's complexity.

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 fully documents the single parameter 'frameSelector' with the instruction 'use >> for nested'. Since schema description coverage is 100%, the description adds no extra parameter meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

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 purpose: 'Get bounding box (x, y, width, height) of the frame in page coordinates.' It uses a specific verb ('Get') and resource ('bounding box of the frame'), and the mention of 'browser_click_at' distinguishes it from other browser tools.

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 gives explicit usage context: 'Use with browser_click_at or to compute relative clicks.' This tells the agent when to use the tool, though it does not explicitly exclude alternatives or list when-not-to-use scenarios.

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