iOS Simulator MCP

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

Annotations already indicate readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe read operation with potentially variable output. The description adds useful context by specifying it returns an 'accessibility element' (implying UI inspection) and operates on the 'iOS Simulator's screen', which clarifies scope beyond annotations. No contradictions with annotations exist.

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, well-structured sentence that front-loads the core purpose ('Returns the accessibility element') and efficiently specifies the context ('at given co-ordinates on the iOS Simulator's screen'). There is no wasted wording, and every part of the sentence contributes essential information.

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?

Given the tool's moderate complexity (UI inspection with coordinates), annotations cover safety and variability, and schema fully documents parameters. However, there is no output schema, and the description does not detail the return value format (e.g., what an 'accessibility element' includes), leaving a minor gap. It is mostly complete but could benefit from output clarification.

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%, with clear descriptions for udid, x, and y parameters. The description adds no additional parameter semantics beyond what the schema provides (e.g., coordinate system details, unit of measurement, or accessibility element format), so it meets the baseline for high schema coverage.

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 ('Returns') and resource ('accessibility element at given co-ordinates on the iOS Simulator's screen'), distinguishing it from siblings like ui_describe_all (which describes all elements) and ui_tap/ui_swipe (which perform actions rather than returning descriptions). The verb 'Returns' is precise and the target is well-defined.

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 implies usage by mentioning 'iOS Simulator's screen' and coordinates, but does not explicitly state when to use this tool versus alternatives like ui_describe_all (for all elements) or ui_view (for view hierarchy). No guidance on prerequisites (e.g., simulator must be running) or exclusions is provided.

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