first_responder

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

No annotations are provided, so the description carries full burden. It accurately describes a read-only inspection tool with no side effects. The information about returned fields (className, frame, canInsertText) is transparent and sufficient.

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 sentence with no wasted words. It conveys purpose, behavioral traits, and usage guidance efficiently.

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?

Given no input schema, no annotations, and no output schema, the description covers the essential aspects: what the tool returns and its role in a workflow. It could mention potential error states, but for a simple info retrieval tool, it is sufficiently 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 tool has no parameters, so schema coverage is 100%. Baseline for 0 parameters is 4. The description adds value by explaining the purpose of the output, which is adequate.

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 retrieves first responder info (className, frame, canInsertText) and explicitly links it to a specific use case: checking focus before typing. This verb+resource specification distinguishes it from sibling action tools like type_text and set_text_at_point.

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 phrase 'Check focus before type_text' provides explicit when-to-use guidance. It does not mention when not to use or list alternatives, but the context is sufficiently clear given the sibling set.

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