ui_type

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

With no annotations provided, the description carries the full burden. It discloses that typing requires a focused field and mentions the AXe CLI dependency. However, it does not explain behavior if no field is focused (e.g., error or no-op), keyboard handling, or delays. This is adequate but not detailed.

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?

The description is two sentences plus a dependency line, front-loading the core purpose. Each sentence earns its place. The dependency line is useful but could be integrated. Very efficient overall.

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 simple tool (type text into a focused field), the description covers the main purpose, prerequisite, and dependency. It does not mention return values (no output schema) or device parameter behavior, but given simplicity and full schema coverage, it is fairly 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 coverage is 100%; both parameters (device, text) are described in the schema. The description adds no additional meaning beyond the schema, such as default values or format details. 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 description clearly states the tool's action: 'Type text into the currently focused field on the simulator.' It uses a specific verb ('Type') and resource ('text into currently focused field'), and distinguishes from siblings like ui_tap (tap to focus) and ui_swipe (swipe).

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 description explicitly says 'Tap a text field first with ui_tap to focus it, then use this to type,' providing a clear prerequisite and sequential usage. It also notes the AXe CLI dependency. However, it does not mention when to avoid this tool or provide alternatives beyond the prerequisite.

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