Browser screenshot

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

The annotations already declare readOnlyHint=true, and the description does not contradict this. The description adds the fact that the output is a PNG screenshot from a browser debug session page, which is useful context, but it does not disclose any other behaviors such as session requirements, pagination, or what happens if the session is invalid. This is adequate given the annotation coverage.

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, front-loaded sentence with no wasted words. It accurately summarizes the core action. However, it is slightly under-specified, as it misses parameter details that could be included concisely, so it does not achieve a perfect 5.

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 no output schema, the description should clarify what the tool returns (e.g., file path, base64 image). It only states the format (PNG) but not the exact return structure. There is also no mention of prerequisites such as an active debug session. The annotation covers read-only safety, but other contextual information is lacking, making this incomplete for a tool of moderate 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?

Schema description coverage is 0%, and the description does not compensate by explaining the parameters. It does not clarify what 'session_id' refers to or what 'full_page' controls. The only implicit hint is 'browser debug session page' in the description, which suggests session_id is the session identifier, but no meaning is provided for full_page. This is a significant gap in a tool with only two parameters.

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 uses a specific verb 'Capture' and a clear resource 'a PNG screenshot from a browser debug session page', which makes the tool's purpose evident. However, it does not explicitly distinguish itself from the sibling tool 'browser_snapshot', which could be confused with this screenshot tool, so it falls short of a 5.

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 versus alternatives like browser_snapshot or browser_console_logs. It simply states what the tool does without any contextual cues or exclusions, leaving the agent to infer appropriate usage from the tool name alone.

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