Tap + screenshot + ask

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It describes the sequence of actions (tap, wait, screenshot, ask) and mentions a wait period before screenshotting. However, it does not disclose what happens if the tap fails, the exact return format (e.g., does it return an image, a text answer, or both?), or any side effects like requiring a running app. The description is adequate for basic behavior but lacks depth on error handling or output, which is significant for a composite tool.

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 two sentences with no redundancy. The first sentence front-loads the action sequence, and the second sentence provides direct usage guidance. Every word serves a purpose, and the structure is clean and immediately understandable. It avoids jargon and is well-scoped.

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 composite tool with 4 parameters and no output schema, the description should cover the response format and any prerequisites. While it clearly states the purpose and usage, it does not mention what the tool returns (e.g., an answer to the question, a screenshot reference) or any necessary preconditions (e.g., the device being interactive). Since there is no output schema, the description's silence on return values leaves an agent without complete information for correctly interpreting the tool's outcome. This is a notable gap, so a 3.

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 100%, so the baseline is 3. The description adds minimal semantic value beyond the schema: it refers to 'wait briefly' which maps to waitMs, and characterizes the question as 'short and specific', but does not explain coordinate units or default wait behavior beyond what the schema provides. The description does not go beyond the schema definitions, so a 3 is appropriate.

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 verb and resource: 'Tap at device screen coordinates (x, y), wait briefly for the UI to react, take a screenshot, and ask a short question about the result - all in one call.' It distinguishes itself from the siblings by defining its specific action (tap) and explicitly contrasting with calling separate tap/screenshot/ask tools. The title also reinforces the composite nature, so there is no ambiguity.

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 when-to-use guidance: 'Use this for any "tap here, then check what happened" step instead of calling separate tap/screenshot/ask tools.' This clearly defines the usage context and names an alternative (separate tools). It does not explicitly mention sibling tools like swipe_and_ask or long_press_and_ask, but the reference to 'tap' inherently implies a distinction from those. This is strong guidance, but not exhaustive about exclusions from all siblings, hence a 4.

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