list_devices

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

No annotations are provided, so the description carries full burden. It discloses that the tool returns ADB state values and explains the serial parameter's optionality ('when exactly one device is attached'). It implies a read-only operation with no mention of side effects, which is appropriate.

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, zero waste. The first sentence states purpose and output, the second gives usage guidance. Information is front-loaded and every word earns its place.

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 simple list tool with one optional parameter and no output schema, the description is complete. It explains what the tool does, what the states mean, and when to use it, leaving no obvious gaps.

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 coverage is 100%, so the schema already describes the 'serial' parameter. The description adds value by explaining the optionality condition ('when exactly one device is attached'), which goes beyond the schema's description.

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 clearly states the tool lists attached emulators/devices and their ADB state ('device', 'offline', 'unauthorized'), with a specific verb ('List') and resource ('attached emulators/devices'). It distinguishes from siblings like boot_emulator or connect_wireless by focusing on listing and state inspection.

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 explicit usage contexts: 'confirm a device is up before driving it' and 'get the serial when several are attached.' It does not explicitly state when not to use it, but given the sibling list contains no alternative listing tools, this guidance is clear and sufficient.

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