Xcode-Studio-MCP

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

With no annotations provided, the description carries the full burden. It successfully discloses the external dependency (idb) and implies coordinate-based interaction, but fails to describe return values, error behaviors (e.g., out-of-bounds coordinates), or whether the operation is synchronous.

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 sentences with zero waste: the first states the action immediately, and the second provides essential prerequisite information. Perfectly front-loaded and appropriately sized for the tool's complexity.

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 4-parameter interaction tool with no output schema or annotations, the description covers the core function and dependency but lacks completeness regarding the coordinate system origin (0,0 location), return value structure, and error scenarios.

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?

Input schema has 100% description coverage, establishing a baseline of 3. The description mentions 'specific coordinates' which aligns with the x/y parameters, but adds no semantic detail beyond what the schema already provides regarding the duration or simulator_udid parameters.

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 specific action ('Tap') and target resource ('iOS Simulator screen'), distinguishing it effectively from siblings like simulator_screenshot (capture), simulator_type (text input), and xcode_build (compilation).

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 critical prerequisite information ('Requires idb') but lacks explicit guidance on when to use this tool versus alternatives like simulator_type, or when tapping is preferable to other interaction methods.

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