Xcode-Studio-MCP

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

No annotations provided, so description carries full burden. It successfully discloses the critical behavioral trait of return format ('base64-encoded PNG') compensating for the missing output schema. Could mention whether this affects simulator state (it shouldn't) or requires specific permissions.

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, zero waste. First sentence states the action, second discloses return format. Perfectly front-loaded with no filler.

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?

Appropriately complete for a simple single-parameter tool. The description compensates for missing output schema by specifying the base64 PNG return format. Minor gap: doesn't specify error behavior if no simulator is booted.

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 coverage is 100%, establishing baseline 3. The description does not add parameter-specific semantics beyond the schema, but the schema already adequately documents the optional simulator_udid parameter with its default behavior.

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?

Clear specific verb ('Capture') + resource ('screenshot of the iOS Simulator screen'). Unambiguously distinguishes from siblings: unlike simulator_describe (metadata), simulator_tap/type (interactions), or xcode_build/run (compilation/execution), this tool specifically captures visual state.

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?

Usage is implied by the action (use when visual verification needed), but lacks explicit when-to-use guidance versus alternatives like simulator_describe, or prerequisites such as requiring a booted simulator.

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