macOS GUI Control MCP

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 adds valuable context about safety ('deletion blocked') which helps the agent understand limitations, but doesn't cover other important behavioral aspects like error handling, permissions needed, or what happens when AppleScript fails. The description provides some behavioral insight but leaves significant gaps.

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 (just 8 words) and front-loaded with the core purpose. Every word earns its place - 'Run arbitrary AppleScript code' states the action, and '(full power, deletion blocked)' adds crucial behavioral context without redundancy. This is a model of efficient description writing.

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 tool's complexity (executing arbitrary code) and lack of both annotations and output schema, the description should do more. While it mentions safety constraints ('deletion blocked'), it doesn't explain what the tool returns, how errors are handled, or what 'full power' entails. For a code execution tool with no structured safety annotations, this is minimally adequate but leaves important gaps.

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?

With 100% schema description coverage and only one parameter, the schema already fully documents the 'script' parameter. The description doesn't add any additional parameter semantics beyond what the schema provides (type, description, requirement). This meets the baseline of 3 for high schema coverage situations.

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 specific action ('Run arbitrary AppleScript code') and the resource ('AppleScript'), distinguishing it from sibling tools like run_shell or keyboard/mouse tools. It provides a precise verb+resource combination that leaves no ambiguity about what the tool does.

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 clear context about when to use this tool ('Run arbitrary AppleScript code') and implicitly distinguishes it from alternatives like run_shell (for shell commands) or other automation tools. However, it doesn't explicitly state when NOT to use it or name specific alternatives, keeping it at a 4 rather than a 5.

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