Build Test

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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false, idempotentHint=false), so the agent knows this is a non-destructive local execution. The description adds the return shape, but since an output schema exists that is largely redundant. It does not mention side effects (build artifacts written, simulator state changes) or any precondition such as a booted simulator.

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?

Three short sentences, zero filler, and the core action is front-loaded ahead of the routing guidance. Every sentence carries distinct information (action, when, alternative, return shape).

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?

With an output schema present and annotations covering the safety profile, the description need not explain return values, and it correctly covers routing. The one omission is preconditions — siblings like build_boot_sim suggest a booted simulator may be required, and that dependency is unstated.

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?

Schema description coverage is 100%, so 'scheme', 'project', and 'device_name' are all fully documented in the schema with examples. The description only alludes to 'the scheme' and 'a simulator', adding no format or constraint detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb and mechanism ('Run xcodebuild test'), names the resource ('the scheme on a simulator'), and explicitly distinguishes itself from the sibling maestro_test. An agent can differentiate it from build_for_sim and maestro_test without opening any schema.

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?

'Use when: running unit/UI tests' gives the trigger condition, and 'For end-to-end Maestro flows use maestro_test' names the alternative and the condition that routes there. Both when-to-use and when-not-to-use are explicit.

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