Xcode MCP 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 mentions the action ('captures') and tool ('xctrace'), but lacks critical behavioral details: whether it's read-only or destructive (e.g., modifies app state), permission requirements, output format (e.g., trace file location), or error handling. For a tool with potential side effects, this is a significant gap.

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 front-loads the core action ('Captures a performance trace') and includes essential context ('using xctrace'). Every word earns its place, making it highly concise and well-structured for quick understanding.

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 no annotations and no output schema, the description is incomplete for a tool with potential complexity. It doesn't explain what the trace output is (e.g., a file, data structure), how to access results, or behavioral risks. For a performance tracing tool, this leaves critical gaps in understanding its full context and 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 parameter descriptions in the schema. The description adds no additional parameter semantics beyond implying 'appPath' targets an application and 'duration' sets trace time. Since the schema already documents these well, the baseline score of 3 is appropriate, as the description doesn't compensate but doesn't detract either.

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 ('captures a performance trace') and resource ('of an application'), specifying the method ('using xctrace'). It distinguishes from siblings like 'run_tests' or 'analyze_file' by focusing on performance profiling rather than execution or analysis. However, it doesn't explicitly differentiate from all siblings (e.g., 'run_xcrun' could also involve tracing), keeping it at 4 rather than 5.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an iOS/macOS app), exclusions (e.g., not for web apps), or compare to siblings like 'run_tests' for functional testing. Without such context, an agent might misuse it in inappropriate scenarios.

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