read_screen

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It mentions 'verified Sky window' and that OCR output is produced, but doesn't disclose details like whether the window must be focused, whether OCR fails gracefully, or what the raw screenshot is retained or discarded. Some useful context but not rich.

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 efficient sentence: 'Capture the verified Sky window and run local OCR.' Zero waste, action-oriented, front-loaded with the verb. Could arguably mention alternatives or output format, but the brevity is appropriate for a simple zero-parameter tool.

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 tool has zero parameters but an output schema exists, which presumably documents the OCR results. The phrase 'verified Sky window' hints at a prerequisite (the window must be verified first, likely by a status/open_chat sibling). For a simple, zero-input capture-and-OCR tool, the description is reasonably complete given the output schema covers return values.

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 tool has zero parameters, so there's nothing for the schema to document and nothing for the description to explain. A baseline 4 is appropriate for a no-parameter tool since parameter ambiguity cannot exist.

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 verb (capture + run OCR) and the resource (the verified Sky window). It names two related sibling tools (screenshot, take_screenshot) but doesn't explicitly distinguish from them beyond mentioning OCR and the Sky window. Purpose is fairly clear with specific scope.

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 implies this is used when you need OCR text from the Sky window rather than a raw image. However, it doesn't explicitly say when to use this vs screenshot/take_screenshot, nor does it state exclusions. The 'verified Sky window' phrase implies a prerequisite state, which is helpful context.

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