da_screenshot

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

Without annotations, the description carries the full transparency burden. It discloses the PNG format and display selection behavior, but fails to mention what happens with the captured screenshot (e.g., returned as binary, saved to file, or returned as path). This leaves a significant gap for agent reasoning.

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?

A single, front-loaded sentence covers the tool's purpose and the key parameter behavior. There is no wasted wording, and the content is efficiently organized.

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 tool with no annotations and no output schema, the description covers the input semantics well but omits any information about the return value or output handling. Since no output schema exists, the description should have disclosed what happens after capture to be complete.

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 provides only type and range for displayId, with zero description coverage. The description fully explains the meaning: null/undefined targets the primary display, while an integer targets a specific display. This adds essential meaning beyond the schema.

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 PNG screenshot, naming the exact resource and output format. It distinguishes between primary display and specific display id, which uniquely identifies this tool among siblings like da_verify_pixels and da_ocr.

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 displayId should be null vs. a specific integer, giving clear usage context for the parameter. It doesn't explicitly mention alternatives, but no sibling tool provides screenshot functionality, so this is acceptable.

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