MCP Appium Server

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

No annotations are provided, so the description carries full burden. It states the action is a 'tap' but doesn't disclose behavioral traits such as whether it waits for the element to be tappable, handles errors if the element isn't found, or what happens on timeout. The mention of 'timeoutMs' in the schema hints at waiting behavior, but the description doesn't elaborate.

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, efficient sentence with zero waste: it states the action, method, and platform constraint without unnecessary words. It is appropriately sized and front-loaded, making it easy to parse quickly.

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 (interactive UI action with two parameters), no annotations, and no output schema, the description is minimally adequate. It covers the basic purpose and platform but lacks details on behavior, error handling, or output, leaving gaps for an agent to infer usage.

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 both parameters ('predicateString' and 'timeoutMs'), including an example for the predicate. The description adds no additional parameter semantics beyond what the schema provides, so it meets the baseline score of 3 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 action ('Tap on an element') and the method ('using iOS predicate string'), with the platform constraint '(iOS only)' explicitly mentioned. It distinguishes itself from generic tapping tools by specifying the iOS predicate approach, though it doesn't explicitly differentiate from similar siblings like 'tap-by-ios-class-chain' or 'tap-element'.

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 context through '(iOS only)', suggesting this tool is for iOS-specific interactions. However, it provides no explicit guidance on when to use this versus alternatives like 'tap-by-ios-class-chain', 'tap-element', or 'inspect-and-tap', nor does it mention prerequisites or exclusions.

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