start_emulator

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

The description discloses key behavioral traits: it initiates boot with quick or cold modes, waits for Android to finish booting, and selects the emulator as active. This adds context beyond the annotations (readOnly=false, openWorld=false), which only indicate mutation and non-open-world behavior. It does not contradict annotations.

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 a single, well-structured sentence that front-loads the primary action and includes all key behaviors without unnecessary words. It is concise and every clause 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?

Given the tool's moderate complexity (4 parameters, no output schema), the description adequately covers the main behavior: starting, booting, and activating. It does not explain return values or timeout failure behavior, but the schema and defaults cover timeout_ms. The context is sufficient for 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 75% (3 of 4 parameters described), so the baseline is 3. The description mentions 'quick or cold boot,' which maps to the boot_mode parameter, but this adds little beyond the schema's own enum and description. It does not elaborate on avd_name, headless, or timeout_ms beyond what the schema already provides.

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's function: start an Android Virtual Device with specific boot modes, wait for boot completion, and select it as active. This specific verb+resource combination distinguishes it from sibling tools like list_avds or connect_device, which serve different purposes.

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 when to use this tool (to start and activate an emulator) and provides clear context about waiting for boot and selecting active. However, it does not explicitly state alternatives or when not to use it, such as preferring connect_device for physical devices.

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