mouseDown

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

No annotations are provided, so the description carries the full disclosure burden and does not meet it. It never states that the press occurs at the current cursor position (implying a prior mouseMove), that the button stays held until mouseUp, or any state/ordering requirements — all essential for a stateful input primitive.

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?

One short sentence with zero padding, which is structurally clean, but the brevity is under-specification rather than effective conciseness for a stateful primitive in a 28-tool suite.

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?

There is no output schema and the tool is simple, so little is strictly required, but for a stateful mouse primitive the missing information — cursor-position dependency and the required mouseUp pairing — is exactly what an agent needs to invoke it correctly alongside its siblings.

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% and the single 'button' parameter is fully documented with an enum and default in the schema, so the description adds nothing but also needs to add nothing. Baseline 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 verb+resource is stated ('press mouse button down'), which is concrete enough to be understood, but it does not differentiate itself from the many overlapping siblings (click, mouseClick, dblclick, press, mouseUp). An agent cannot tell from this text why it would use mouseDown rather than click.

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 when-to-use guidance at all. In a suite containing click, mouseClick, dblclick, mouseUp, and mouseMove, the description never explains that this is a low-level primitive typically paired with mouseUp (e.g. for drag or hold gestures) rather than a standalone action.

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