build_run_sim

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 explicitly states the tool will boot the simulator if needed, install and launch the app, automatically capture runtime logs, and include the log file path in the response. This discloses key side effects and response behavior beyond what annotations would provide. However, it does not mention prerequisites like a project/scheme or what happens on build failure, so it's not exhaustive but still strong.

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 three short sentences, each earning its place: the main action, the log-capture behavior, and the preferred usage context. It is front-loaded with the core purpose and contains no redundant or filler content.

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?

The description covers the tool's purpose, side effects, response contents (log file path), and when to prefer it. Given the moderate complexity of the tool, two optional parameters, and no output schema, this is nearly complete. It could mention failure handling or default setup requirements, but the essential information for an agent to select and invoke the tool is present.

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 has 100% description coverage, with both parameters (extraArgs and launchArgs) clearly described as build settings vs. app launch arguments. The tool description adds no additional parameter-specific semantics beyond what the schema already provides, so the baseline 3 applies.

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 tool's action: 'Build, install, and launch on iOS Simulator, booting it when needed.' This is a specific verb+resource combination that distinguishes it from siblings like build_sim (build only) and launch_app_sim (launch only). The phrase 'Preferred single-step run tool' further sets it apart as a combined build+run workflow.

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 a clear usage condition: 'Preferred single-step run tool when defaults are set.' This tells the agent when to prefer this tool over alternatives, implying it should be used for building and launching in one step when default settings are configured. It doesn't explicitly list alternatives or exclusions, but the sibling tool names and the 'preferred' phrasing give enough guidance for most scenarios.

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