Echo

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

The description adds 'validated text' which suggests input validation, beyond what annotations provide (readOnlyHint, idempotentHint). Annotations already indicate a safe, idempotent operation. The description complements them without contradiction.

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, clear sentence with no extraneous words. It is front-loaded and perfectly concise for the tool's simplicity.

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 simplicity, good annotations, and existence of an output schema, the description is complete. It explains the core functionality and return value without requiring further detail.

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 0%, so the description must compensate. It mentions 'validated text' which hints at validation (likely the min/max length) but does not explicitly describe the 'message' parameter's purpose. The parameter is named 'message', so its purpose is partially inferable, but more detail would be better.

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 returns validated text and Unicode character count. This goes beyond the name 'echo' by specifying the output includes validation and character count, distinguishing it from a simple echo. With no sibling tools, there is no ambiguity.

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 implies usage for getting character count of validated text. Since there are no sibling tools, explicit when-to-use or alternatives are not critical. The description is straightforward and sufficient for a simple utility tool.

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