MCP Appium Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool 'sets' a preference, implying a write/mutation operation, but doesn't specify if this requires specific permissions, whether changes are persistent across simulator sessions, potential side effects, or error handling. This is a significant gap for a mutation tool with zero annotation coverage.

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—'Set a specific simulator preference' directly conveys the core action. It's 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 complexity of a mutation tool with no annotations and no output schema, the description is inadequate. It doesn't explain what happens after setting the preference (e.g., success response, error cases), behavioral traits like idempotency or side effects, or how it relates to sibling tools. For a 4-parameter write operation, more context is needed.

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 all four parameters (udid, domain, key, value). The description adds no additional meaning beyond the schema, such as examples of valid domains/keys or format constraints. Baseline 3 is appropriate since the schema does the heavy lifting.

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 'Set a specific simulator preference' clearly states the action (set) and target (simulator preference), but it's vague about what 'preference' entails—it could mean configuration settings, system preferences, or app-specific options. It doesn't distinguish from sibling tools like 'xcode_configure_simulator_preferences', which might handle broader configuration vs. this tool's specific key-value setting.

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?

No guidance is provided on when to use this tool versus alternatives. For example, it doesn't mention if this is for fine-grained settings vs. using 'xcode_configure_simulator_preferences' for bulk configuration, or prerequisites like needing a booted simulator. The description alone offers no usage context.

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