device_list

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so no contradiction. The description adds useful context that results are a flat enumeration (serial, state, model) and lists all connected devices. With annotations carrying the safety profile, the description contributes meaningful detail about the return contents.

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?

Single sentence, zero waste, every word earns its place. Front-loaded with the verb and resource immediately.

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?

A 0-parameter list tool with a readOnlyHint and an output schema is well-served by this description. It names the three data fields returned, which effectively covers what's needed. Slight deduction because it doesn't hint that the output schema provides the full return shape, but for a simple listing tool this is close to complete.

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?

Zero parameters means the schema has nothing to cover; schema description coverage reports 100% trivially. The description explains what data is returned per device (serial, state, model), which gives the agent an accurate picture of expected output, compensating for the lack of an explicit return format explanation.

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?

Clear verb (list) + resource (Android devices) + specifics (serial numbers, state, model). Distinct from siblings like device_info (which focuses on single device detail) and version (tool versions). The readOnlyHint and openWorldHint annotations align with the descriptive, safe nature of listing 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?

Implied usage is clear — this is the way to discover available devices before starting sessions or interactions. However, no explicit when-to-use guidance is offered, nor is an alternative named. Lacks the strong when-not guidance seen in top-tier tools.

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