macOS GUI Control MCP

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action but doesn't cover critical aspects like whether it moves the cursor first, if it requires specific permissions, or what happens on failure (e.g., if coordinates are off-screen). This leaves significant gaps in understanding the tool's behavior.

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 extremely concise with a single, front-loaded sentence that directly states the action. There is no wasted verbiage, making it efficient and easy to parse.

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 complexity (a mouse action with coordinates), lack of annotations, no output schema, and poor parameter documentation, the description is incomplete. It doesn't address behavioral nuances, error conditions, or practical usage details needed for effective tool invocation.

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?

The schema has 0% description coverage for its two parameters (x and y), and the description doesn't add any semantic meaning beyond 'coordinates'. It fails to specify units (e.g., pixels), coordinate system origin, or valid ranges, which are essential for correct usage.

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 action ('Double-click') and target ('at coordinates'), making the purpose understandable. However, it doesn't differentiate from sibling tools like 'mouse_click' or 'mouse_right_click', which would require specifying the double-click behavior more explicitly relative to single clicks.

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?

No guidance is provided on when to use this tool versus alternatives like 'mouse_click' or 'mouse_right_click'. The description lacks context on scenarios requiring double-clicks over single clicks or other mouse actions, leaving usage unclear.

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