Click at specified viewport coordinates from a recent screenshot to focus or activate the piano, ensuring no keys are held down.
Click viewport coordinates from a recent screenshot to focus or activate the piano. No keys may be held.
| Name | Required | Description | Default |
|---|---|---|---|
| x | Yes | ||
| y | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=false, destructiveHint=true, and openWorldHint=true. The description adds behavioral context about requiring a recent screenshot and prohibiting held keys, but does not describe side effects, permissions, or response behavior. It does not contradict the 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?
Two short sentences, each earning its place. The first is the action and purpose, the second is a constraint. No wordy filler or repetition of schema information, and the key action is front-loaded.
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 taking only two integers and no output schema, the description explains the source of coordinates, the intended action, and an important constraint. It doesn't mention return values or failure modes, but a click action with minimal parameters is adequately specified without them.
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 0%, so the description must carry the meaning of x and y. The phrase 'viewport coordinates' does add semantics, indicating the numbers are pixel coordinates in the viewport shown in the screenshot. However, it doesn't specify the coordinate origin (e.g., top-left) or units, leaving some ambiguity.
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?
States a specific verb 'Click' and a specific resource 'viewport coordinates from a recent screenshot', with the clear purpose 'to focus or activate the piano'. This distinguishes it from siblings like key_down/key_up, which are about keyboard events, and browser_screenshot which captures the image.
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?
Provides clear context by specifying the coordinates come from a recent screenshot, implying the agent should take a screenshot first. The 'No keys may be held' constraint is a limiting rule. It doesn't name alternative tools explicitly, but the distinction from key-based interactions is clear enough for an agent to infer when to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.