Screenshot as escalation

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

The description discloses a side effect of scrolling to center when an id is passed, which is beyond the readOnly/idempotent annotations. It does not contradict annotations, and the readOnly hint covers the lack of destructive actions.

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 concise, using two sentences with a stylistic flair ('Pixels as ESCALATION'). It is slightly unconventional but conveys all necessary information without unnecessary verbosity.

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 provides enough context for operation, including when to use it and a sibling reference (browser_verify). It does not specify the output format, but this is not required given the absence of an output schema and the typical nature of screenshot tools.

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?

Both parameters (id, sessionId) are fully described in the schema, and the description adds context about the id being used to center an element. Since schema coverage is 100%, baseline is appropriate and no additional meaning is provided.

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 captures a screenshot ('snapdom render') of the viewport or a specific element when an id is passed. It also distinguishes itself from browser_verify by emphasizing visual-only use cases.

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?

Explicit guidance is provided: use only when visual doubt exists (layout, color, overlap) and not as a default; for changes, use browser_verify. This directly tells the agent when to choose this tool over alternatives.

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