Get ScreenApp usage

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the non-obvious behavioral fact that calling this tool does not consume credits, which is valuable beyond the annotations and not contradicted by them.

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 sentences, with the core purpose front-loaded and the second sentence adding only the non-obvious credit assurance. Every word earns its place and nothing extraneous is included.

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 zero-parameter, read-only tool with rich annotations, the description is complete: it states the resource, the type of data, and a behavior that matters to callers. No output schema is present, so the description's high-level promise of usage and billing counters is sufficient guidance.

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?

There are no parameters, so the schema carries no parameter meaning to compensate for; the 0-param baseline of 4 applies. The description's mention of 'usage and billing counters' adequately frames what the returned data represents.

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 names a specific verb, 'Read', and a distinct resource, 'ScreenApp usage and billing counters,' which clearly separates it from the recording-, transcript-, profile-, and team-oriented siblings. The title reinforces the resource without ambiguity.

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 statement 'Read ScreenApp usage and billing counters' provides clear context for when to call the tool, and 'This does not consume credits' signals it is a low-cost informational call. It does not explicitly name sibling alternatives or exclusions, but none are needed for a zero-parameter read-only counter.

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