xcode-mcp

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

No annotations are provided, so the description carries full burden. It states the action ('Open') but doesn't disclose behavioral traits such as what happens if the simulator isn't running, whether this requires specific permissions, error conditions, or the expected outcome (e.g., opens in browser vs. app). For a mutation tool with zero annotation coverage, this is insufficient.

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 that directly states the tool's purpose without unnecessary words. It's front-loaded and wastes no space, 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 (a mutation tool with no annotations and no output schema), the description is incomplete. It doesn't explain what 'Open' entails behaviorally, potential side effects, error handling, or return values. For a tool that interacts with simulators, more context is needed to use it effectively.

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 both parameters (device and url). The description doesn't add any meaning beyond what the schema provides (e.g., no examples of deep link formats or device selection strategies). Baseline 3 is appropriate when 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 clearly states the action ('Open') and target ('a URL or deep link on a simulator'), making the purpose immediately understandable. It doesn't explicitly distinguish from siblings like simctl_launch (which might launch apps) or simctl_push (which might push notifications), but the specific focus on URLs provides reasonable differentiation.

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 about when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a booted simulator), exclusions, or relationships with sibling tools like simctl_launch (for app launching) or simctl_boot (for starting simulators). The description assumes context without providing usage context.

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