ui_tap

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It only states the basic tap action, but omits behaviors implied by optional parameters such as duration (long press), udid targeting, and any side effects or results. The description is too minimal for a tool with additional configurable behavior.

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 a single, clear sentence with no filler words. The prefix '[ios-simulator-mcp]' provides context and every word earns its place. It is appropriately concise.

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 tool with 4 parameters, no annotations, and no output schema, the description is incomplete. It does not explain optional behaviors like duration, how to select a simulator via udid, or what the tool returns. A basic tap is understood, but the full context of usage is missing given the richer parameter set.

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?

The input schema describes all parameters, achieving 100% coverage, so the baseline is 3. The tool description adds no parameter meaning beyond the schema. However, the schema contains a notable typo (the description for 'y' says 'The x-coordinate'), which the tool description does not correct, so no added clarity is provided.

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 ('Tap') and resource ('the screen in the iOS Simulator'), which is a specific verb+resource combination. It distinguishes from sibling tools like ui_type and ui_swipe by indicating a precise interaction type.

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 provides no guidance on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or scenarios where tapping is appropriate versus other UI interactions. Sibling tools like ui_type and ui_swipe are distinct but no comparative guidance is given.

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