Click at screen coordinates or on a macOS UI element using an element_index from the latest accessibility state; returns an error when that index is stale.
Click at {x,y} or on a UI element, with optional button (left|right|middle) and count. Use element_index from the latest mac_ax_state (valid 30s); returns element_no_longer_valid when stale.
| Name | Required | Description | Default |
|---|---|---|---|
| x | No | ||
| y | No | ||
| count | No | ||
| button | No | ||
| element_index | No |
Changes observed during successful MCP inspections.
v0.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden, and it does disclose a real behavioral trait: the 30-second staleness window on element_index and the specific failure mode element_no_longer_valid. It omits other useful traits such as whether the click steals focus or what a right-click triggers.
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 tight sentences with zero filler, and the core action plus targeting modes are front-loaded before the staleness caveat.
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?
With no annotations, no output schema, and five undocumented parameters, the description covers the essentials an agent needs to invoke it correctly, including the cross-tool dependency and error code. Minor gaps remain around coordinate frame and default button/count behavior.
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 0%, so the description must compensate, and it largely does: it enumerates the button values (left|right|middle), explains count as repetition, and ties element_index to mac_ax_state and its validity window. It does not clarify whether x/y are screen-absolute or window-relative, nor default values for count or button.
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) with two precise targeting modes (coordinates or UI element) plus the optional button and count modifiers. An agent can immediately distinguish this from mac_drag, mac_scroll, and mac_key without inspecting any schema.
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?
Gives an explicit prerequisite for the element path: use element_index from the latest mac_ax_state, valid for 30s. It does not say when to prefer coordinates over element_index, so the choice between the two modes is left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.