Echo

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

With no annotations, the description must carry behavioral meaning; 'echo back' clearly communicates a non-mutating pass-through operation and 'optionally repeated' adds the only behavioral variant. It does not explicitly state the absence of state changes, but the echo semantics strongly imply it.

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 eight words long and front-loads the core operation, followed by the optional qualifier. Every word contributes meaning with no 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?

This is a minimal, single-purpose tool with fully documented parameters, no siblings, and an output schema present. The description, combined with the schema, is sufficient for an agent to select and call it correctly.

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 coverage is 100%, so the parameter semantics already live in the input schema. The description's 'optionally repeated' maps to the times parameter but adds no range, formatting, or ordering details beyond what the schema already states.

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 names the exact operation ('Echo a message back') and the object it operates on (a message), and adds the optional repetition behavior. With no sibling tools to differentiate, this is fully 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 gives clear context that this tool simply returns a provided message, optionally repeated. There are no siblings or exclusions to document, so the intended use is evident from the purpose statement, though no explicit when/when-not guidance is given.

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