Taps pixel coordinates from a captured screenshot to simulate user touches, matching the screenshot scale for accurate targeting and optional screen-settle waits.
Tap a point given in pixels of a screenshot you took (set scale to the same value as the screenshot).
| Name | Required | Description | Default |
|---|---|---|---|
| x | Yes | ||
| y | Yes | ||
| scale | No | ||
| settle | No | wait for the screen to change and settle before returning | |
| timeout | No | ||
| stable_for | No | ||
| wait_change | No |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the whole burden. It does not disclose that this is a synthetic input injection, what the tap does to app state, whether it blocks, or what the four timing parameters (settle, timeout, stable_for, wait_change) control; only the coordinate/scale behavior is conveyed.
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?
A single tight sentence with the coordinate frame front-loaded and the critical constraint in a parenthetical. Nothing is wasted, though the brevity comes at the cost of omitting needed detail.
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 7-parameter action tool with no annotations and no output schema, the description is far too thin: the wait/settle semantics, default behavior, and return values are all unaddressed, leaving an agent unable to reason about the four timing knobs.
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 only 14%, so the description must compensate and it only partially does: it clarifies that x/y are screenshot pixels and that scale must equal the screenshot's scale value, which is genuinely non-obvious. The remaining timing parameters (timeout, stable_for, wait_change, and partly settle) are left entirely undefined in both schema and description.
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 (tap) and a specific coordinate frame (pixels of a screenshot you took), which distinguishes it in spirit from the sibling `tap` and from `tap_element`/`tap_css`. It never names those alternatives outright, so the differentiation is inferred rather than stated.
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 phrase 'a screenshot you took' implies the workflow (capture, then tap in that image's pixel space) and the parenthetical tells the caller to match scale. There is no explicit when-to-use vs. `tap`, `tap_element`, or `tap_css`, and no statement of preconditions or failure modes.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.