ios_doctor

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

Annotations already declare this tool read-only, non-destructive, and idempotent. The description adds meaningful behavioral information: it is a diagnostic preflight that provides concrete remedies for every failing check. This tells the agent what kind of output to expect and reinforces a safe, non-mutating behavior.

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 compact, front-loaded with the core purpose, and every sentence adds value. The second paragraph gives concrete usage triggers, and the final clause sets expectations for the output. There is no fluff or repetition of structured metadata.

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 zero parameters, existing output schema, and comprehensive annotations, the description is complete. It covers what the tool does, when to run it, how it fits into the workflow, and what kind of result it produces. Nothing essential is missing for an agent to invoke it correctly.

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 the description has no parameter semantics to convey. The schema fully documents this with an empty properties object. A baseline of 4 is appropriate because no additional parameter meaning is needed.

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 uses a specific verb ('Check') and a clear resource ('that this machine can drive an iOS device'), and states the output ('say how to fix what it can't'). This cleanly distinguishes the tool from diagnostic siblings like ios_list_devices or ios_session_status, which focus on device presence or session state rather than host readiness.

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 explicitly says when to run this tool: when a session fails to start, when a device does not appear, or after an Xcode/iOS upgrade. 'Run this first' also gives ordering guidance. It does not explicitly name excluded alternatives, but the conditional triggers are clear enough.

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