echo

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 discloses the core behavior (echoing back input) and the optional modifiers (repetition, prefix). It does not cover edge cases like zero or negative repetition, but for a simple echo tool this is adequate. It adds meaningful behavioral context beyond the schema.

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, efficient sentence that front-loads the core action and mentions the two optional modifiers. No wasted words.

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 with no output schema and a trivial return value, the description is sufficient. It explains the action and the parameters' purpose. Minor gaps like default behavior of repeat or prefix concatenation rules are not critical for an echo 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?

Schema description coverage is 100% – each parameter already has a clear description. The tool description's mention of 'optional repetition and prefix formatting' merely reiterates the schema. It adds no new semantic detail, so the baseline of 3 applies.

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 clear verb ('echoes back'), a specific resource ('the input message'), and the optional behaviors (repetition and prefix formatting). It is unambiguous and naturally distinguished from the sibling tools, which are unrelated in function.

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 does not explicitly mention when to use this tool vs alternatives, but the siblings (get_system_info, my_custom_tool) are so different in purpose that no exclusion is necessary. The context is clear, though not explicitly stated.

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