Say Hello MCP World

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

There are no annotations, so the description carries the behavioral burden; however, the behavior is fully disclosed as a greeting action with no parameters. It doesn't discuss side effects or permissions, but for a simple no-argument hello tool this is not a meaningful gap, especially since an output schema exists.

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?

A single sentence front-loads the action and then states the trigger condition. There is no redundant restatement of the title or filler.

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?

For a parameterless, sibling-less tool with an output schema, this description is complete: it names the behavior and specifies when it should be invoked. No additional context is needed for correct invocation.

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 tool has zero parameters, so the baseline is 4. The description correctly adds no parameter claims, and there is nothing for an agent to misinterpret at call time.

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 uses a specific verb ('say hello') and identifies the target ('the MCP world'), with a clear condition that limits its scope. It is unambiguous and the title and name align, so an agent knows exactly what operation this tool performs.

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?

It states the only valid trigger: 'when the user explicitly requests it.' With no sibling tools listed, this explicit when-condition is sufficient guidance for selecting the tool and implies it should not be used unprompted.

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