Echo a message

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

With no annotations, the description carries the burden of disclosure. It clearly conveys that the tool performs no transformation and returns the message exactly as provided, implying a safe, stateless operation. It does not mention error cases or side effects, but there is no indication any exist.

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?

Two sentences, no filler: the first states behavior, the second gives practical context. The important verb-and-echo concept is front-loaded.

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 tool this simple, the description is complete. It defines the sole parameter, the behavior, and the use case, and the lack of an output schema is acceptable because the tool's output is obvious from 'echoes ... back verbatim.'

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 schema provides zero description coverage, so the description must compensate. It does by clarifying that the `message` parameter is the input that will be echoed back verbatim. This is sufficient for a single-string parameter, though more detail about constraints or format could be added.

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 states a specific verb and resource: 'Echoes a message back verbatim.' This clearly differentiates it from siblings like say_hello, get_server_time, and add, all of which have different behaviors.

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 explicitly states its use: 'Useful for verifying that the connection between the client and this MCP server is healthy.' It does not describe when not to use it or list alternatives, but the intended context is clear.

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