Capture a screenshot of a renderer

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

With no annotations, the description discloses use of 'Page.captureScreenshot' and that it returns base64, hinting at payload size. However, it lacks details on permissions, side effects, or whether it is read-only. Some behavioral context is given but not comprehensive.

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?

Two succinct sentences. First sentence states core action and method, second provides key tip. No unnecessary words. Perfectly front-loaded.

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?

The description explains return format (base64) and hints at full-page mode, but does not cover all parameters or expected output beyond base64. Given no output schema and moderate parameter count, it leaves some gaps for an agent to infer, but is minimally viable.

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 coverage is 100%, so baseline is 3. The description adds value by noting that 'fullPage: false' is the default and preferred for quick-look, which goes beyond schema descriptions. It also mentions base64 return, aiding parameter comprehension.

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 it captures a screenshot of a target renderer using specific verb 'Grab' and resource 'screenshot of a renderer'. It uniquely identifies the tool among siblings like 'list_windows' and 'evaluate'.

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 practical guidance: prefer 'fullPage: false' for quick-look snapshots due to large payloads. This helps the agent decide when to use the default mode, though it does not explicitly exclude alternatives or state when not to use the tool.

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