Types text into an iOS simulator's active input field, optionally tapping a target element first to focus it before entering the provided string.
Type text (tap input field first to focus, or provide predicate).
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | Text to type | |
| device_id | Yes | Simulator UDID | |
| predicate | No | Tap element first |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description carries the full behavioral burden. It omits whether typed text replaces or appends to existing content, what happens if no field is focused, failure modes, or permission/setup requirements for the simulator.
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 front-loaded sentence with a parenthetical qualifier, no filler. It is efficient, though the parenthetical slightly muddles what predicate does relative to the preceding tap instruction.
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?
An output schema exists so return values need no explanation, and all three params are documented. Still, for a UI input mutation with zero annotations, the behavioral gaps (append vs replace, focus failure) leave it only minimally complete.
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%, so the schema already documents text, device_id, and predicate. The description only adds a marginal gloss on predicate ('tap element first'), which is already conveyed by the schema's own 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+resource ('Type text') that is clearly distinct from the tap/swipe/press siblings. It does not, however, explicitly contrast itself against keyboard-adjacent siblings like dismiss_keyboard, so it stops short of full differentiation.
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 parenthetical gives a procedural precondition ('tap input field first to focus, or provide predicate') which implies when the tool works, but never states alternatives or exclusions against sibling input tools. Usage context is implied rather than spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.