hello_world

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

No annotations are provided, so the description carries the full burden. It states the tool returns a greeting, implying it's a read-only operation, but doesn't explicitly mention side effects, permissions, or rate limits. The description adds basic behavioral context (e.g., it's an example tool), but lacks details on error handling or performance characteristics. This is adequate for a simple tool but minimal.

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 front-loaded with the core purpose but includes meta-commentary about FastMCP that doesn't aid tool selection. The Args and Returns sections are structured but could be more integrated. Overall, it's reasonably concise but has some extraneous information (e.g., the example tool note), reducing efficiency.

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 low complexity (one optional parameter) and the presence of an output schema (implied by 'Returns' in description), the description is mostly complete. It covers purpose, parameters, and return values adequately. However, it lacks usage context or error information, which is a minor gap for such a simple tool.

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 description adds significant meaning beyond the input schema, which has 0% description coverage. It explains the 'name' parameter as 'The name to greet. Defaults to "World".' This clarifies the parameter's purpose and default value, fully compensating for the schema's lack of descriptions. For a single parameter tool, this provides complete semantic understanding.

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 purpose: 'Return a friendly greeting.' It specifies the verb ('return') and resource ('greeting'), though it doesn't differentiate from siblings since this is a simple example tool with unrelated functionality to other tools on the server. The purpose is specific and unambiguous.

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 mentions it's 'an example tool that demonstrates the basic pattern for creating MCP tools with FastMCP,' but this is meta-commentary rather than usage guidance. There's no indication of practical application contexts or when it might be preferred over other greeting-related tools (though none exist in siblings).

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