List Devices

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

Annotations already declare readOnlyHint=true. The description adds valuable behavioral context beyond that: it lists physical devices, simulators, and emulators, and clarifies that both Android and iOS are included. It does not mention output format details, but the added scope information is meaningful for a read-only list tool.

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 two short sentences with the main action front-loaded ('List all available devices'). Every sentence contributes meaning, and there is no redundancy or filler.

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 tool with no input parameters and no output schema, the description adequately covers the tool's purpose and scope. It explains what devices are returned (physical, simulator, emulator; Android, iOS), which is sufficient for an agent to select and invoke the tool 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 zero parameters, and schema coverage is 100% by default. The description adds no parameter-specific details because none exist, but the baseline of 4 is appropriate for a no-parameter tool, and the description clarifies the result set (available devices across platforms).

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 ('List') and resource ('available devices'), clearly distinguishing it from sibling tools related to orientation, screen recording, crashes, and apps. It also specifies the scope: physical devices, simulators, and emulators, across both Android and iOS.

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 provides clear context about what the tool returns (both platforms, physical and virtual devices), effectively indicating when to use it. It does not explicitly name alternatives or exclusions, but no sibling tool performs a similar listing function, so the usage context is sufficient.

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