List Devices

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe-read profile is covered. The description adds real context beyond that: the devices are local, already connected, cost nothing, and include both emulators/simulators and physical Android/iOS hardware. It does not describe the return shape (e.g. device IDs or ordering), which keeps it short of a 5.

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?

Four tight sentences with the core capability front-loaded and the alternative routing placed last. Every sentence carries distinct information (scope, device types, platforms, locality/cost, alternative).

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 listing tool with no output schema, the description covers scope, platform coverage, locality, cost, and the sibling alternative. Nothing required to call it correctly is absent.

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 takes zero parameters, so the baseline is 4 and there is no parameter behavior an agent could misconstrue. No parameter-level detail is needed or missing.

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 precise verb+resource (list available devices) and immediately scopes it to local physical devices plus simulators/emulators across Android and iOS. It explicitly distinguishes itself from the similarly named sibling mobile_list_remote_devices, so an agent can route without opening either 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?

Gives an explicit when-to-use (local devices 'ready to use immediately at no cost') and an explicit when-not plus the named alternative ('for devices from the shared remote cloud fleet, use mobile_list_remote_devices instead'). This is the routing information an agent needs.

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