MCP Safari Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states what the tool does but doesn't describe important traits: whether execution is synchronous/asynchronous, error handling, security implications, performance impact, or what happens if the page isn't loaded. For a JavaScript execution tool with zero annotation coverage, 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 wasted words. It's appropriately sized for a simple tool and front-loads the essential information (execute JavaScript in Safari). Every word earns its place.

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 this is a potentially powerful JavaScript execution tool with no annotations and no output schema, the description is incomplete. It doesn't explain what the tool returns (e.g., the result of the last expression), error conditions, or security considerations. For a tool that could have significant side effects, more context is needed.

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%, so the schema already documents the single 'script' parameter completely. The description doesn't add any parameter semantics beyond what's in the schema (e.g., examples of valid JavaScript, constraints on script length or complexity). Baseline 3 is appropriate when the schema does all the parameter documentation work.

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 ('Execute JavaScript') and target ('in the current Safari page'), providing a specific verb+resource combination. However, it doesn't distinguish this tool from potential alternatives like browser automation tools that might have similar functionality, which prevents a perfect score.

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 (like needing a page to be loaded), exclusions (like what types of scripts might fail), or relationships to sibling tools (like get_console_logs for debugging). This leaves the agent with minimal context for tool selection.

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