echo

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

With no annotations, the description carries the full behavioral burden, but it does convey the key trait: the output equals the input with no mutation, implying a pure, side-effect-free operation. It omits any statement about error behavior (contrast echo_error) or size limits (contrast echo_large).

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?

One sentence, no preamble, and the effect is stated immediately. Nothing is wasted and nothing is buried.

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?

An output schema exists, so return-value explanation is unnecessary, and the tool has only one required string parameter. Still, the crowded echo_* sibling family means an agent gets no help distinguishing this from echo_error or echo_types, leaving a real gap for such a simple definition.

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% and the single 'message' property has no per-field documentation. The phrase 'the input message' loosely ties to the parameter but adds no constraints, format, or example beyond what the schema already declares as a required string.

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 a specific operation and its exact effect: the input message is returned unchanged. That distinguishes it from transformation siblings like string_reverse or string_uppercase. It does not, however, differentiate it from the many echo_* variants (echo_error, echo_large, echo_nested), so it stops short of a 5.

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?

Usage is only implied: a pass-through tool is naturally used to test pipelines or inspect payloads, and the description says nothing explicit about when to choose it over echo_large or echo_nested. No exclusions or alternatives are named. For a trivial tool this is adequate but thin.

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