device.start_emulator

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

Despite no annotations being provided, the description front-loads important behavioral flags: 'approval required,' 'device mutation,' and 'risk:dangerous.' It also discloses completion behavior ('Returns after launching or optional boot wait'), which is meaningful for a mutation tool. However, it does not describe failure modes, side effects, or state changes beyond starting an emulator.

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 compact and efficient. The risk flags appear first, followed by a clear one-sentence specification of the action and return behavior. No filler words are present.

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 annotations, no output schema, and three parameters, the description is thin. It fails to explain timeoutMs, mention how to obtain valid AVD names, describe what happens if the emulator is already running, or provide any error/failure semantics. The description does not fully equip an agent to 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?

Schema description coverage is 0%, so the description must compensate. It explains avdName ('by AVD name') and partially covers waitForBoot ('optional boot wait'), but timeoutMs is never described. The meaning, units, and behavior of timeoutMs are left entirely unspecified, leaving a significant gap.

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: 'Start an Android emulator by AVD name.' This clearly identifies the tool's function and distinguishes it from siblings like device.stop_emulator and ios.boot_simulator. The scope is unambiguous.

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 implies usage through its name and wording, but there is no explicit guidance on when to use it versus alternatives, no preconditions such as listing available AVDs first, and no exclusion such as 'for iOS, use ios.boot_simulator.' Usage context is left to inference.

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