list_devices

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

With no annotations, the description carries the behavioral disclosure burden. It communicates that the tool is a read-only listing operation and clarifies the adb states it reports. It does not explicitly state the absence of side effects, but 'List' and the focus on device state strongly imply a safe, non-mutating operation.

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 first two sentences are concise and front-loaded with essential information. However, the third sentence about the React Native/Expo guide is tangential to listing devices and introduces workflow advice that may belong elsewhere. It slightly dilutes the tool-focused message.

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 tool with one optional parameter and no output schema, the description covers the core action, expected state values, and practical use cases. It could be more complete by explicitly describing the return format, but the description is sufficient for an agent to understand what will happen.

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% and the schema already documents the 'serial' parameter with its optionality and adb -s semantics. The description adds marginal context by mentioning serial retrieval when multiple devices are attached, but it does not meaningfully supplement the schema.

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 states a specific verb and resource: 'List attached emulators/devices and their adb state'. It also defines the state values (device, offline, unauthorized), making the tool's function unambiguous. This distinguishes it from sibling tools like list_avds, which target AVDs rather than attached devices.

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 tells the agent when to use this tool: 'confirm a device is up before driving it' and 'get the serial when several are attached'. It does not explicitly mention alternatives or exclusions, but the usage contexts are clear enough for an agent to decide.

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