Drag from one Android screen coordinate to another in display pixels, with configurable duration plus optional observation and wait conditions; executes a single drag without replay.
Drag once from start {x,y} to end {x,y}, in Android display pixels. Supports duration, observation_id, wait_for and observe. No automatic replay.
| Name | Required | Description | Default |
|---|---|---|---|
| end | Yes | ||
| start | Yes | ||
| observe | No | none | |
| duration | No | ||
| wait_for | No | ||
| variation | No | ||
| observation_id | No |
Changes observed during successful MCP inspections.
v0.7.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the mutating, non-repeatable nature is partly covered. The description adds genuinely useful behavior beyond that: a single drag execution and 'No automatic replay', which tells the agent it must re-issue calls itself. It says nothing about timing side effects, failure modes, or what the returned observation contains.
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, front-loaded with the action and coordinate system before the modifier list. The trailing parameter enumeration is low-value filler but not verbose enough to hurt.
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?
Seven parameters with zero schema descriptions, no output schema, and an open-world mutating annotation set is a heavy burden the description does not carry. Four parameters are named without semantics and `variation` (with its bounded-randomization semantics) is never mentioned, so an agent cannot confidently compose a call with waiting or observation.
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% — the schema only supplies titles, ranges and defaults. The description merely lists four parameter names (duration, observation_id, wait_for, observe) without explaining what any of them do, what observe modes return, or what wait_for waits on, and it omits `variation` entirely. Only the start/end pixel units are meaningfully clarified.
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?
Names a concrete verb and gesture ('Drag once from start {x,y} to end {x,y}') and pins the coordinate system to Android display pixels, which is a real ambiguity resolved. It does not, however, distinguish itself from the close sibling aua_swipe or from aua_scroll_until, so an agent must infer the difference from 'Drag once' and 'No automatic replay'.
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?
'Drag once' plus 'No automatic replay' implies this is a single-shot gesture rather than a repeated or scroll-like motion, which weakly separates it from aua_swipe. There is no explicit when-to-use statement, no named alternative, and no precondition (e.g., element already located via aua_locate) before calling.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.