take_simulator_screenshot

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

Beyond the idempotentHint and readOnlyHint annotations, the description discloses the return value (file path), error conditions (XCodeMCPError for no booted simulators or failure), and the fallback behavior when UDID is omitted. This adds significant behavioral context.

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 extremely concise: a one-line purpose followed by structured Args/Returns/Raises sections. Every sentence is informative and there is no fluff. The structure is front-loaded with the core action.

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 simple tool with one parameter and an output schema, the description covers purpose, parameter behavior, return value, and error handling. Annotations provide safety guarantees. It is fully complete without being verbose.

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 only defines udid as an optional string/null. The description adds meaning by explaining its purpose (device identifier), the fallback to first booted simulator, and how to find UDIDs with list_booted_simulators. With 0% schema coverage, this fully compensates.

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 'Take a screenshot of a booted iOS simulator', providing a specific verb and resource. It distinguishes from sibling tools like take_app_screenshot or take_window_screenshot which target different contexts.

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 explains that an optional UDID can be provided, and if omitted the first booted simulator is used, with a pointer to list_booted_simulators for discovery. It does not explicitly compare to alternative screenshot tools but the context makes the use case clear.

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