Echo

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and side-effect expectations. The description adds minimal behavioral context, mainly 'validated', which hints that inputs are checked but not how. No contradiction with annotations; the bar is lower, so a 3 is appropriate.

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, direct sentence with no unnecessary words. The verb is front-loaded, and the optional part is clearly flagged. Every word earns its place.

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 trivial echo tool, the description is nearly sufficient. The output schema exists, and annotations cover read-only/idempotent behavior, so return-value details are not needed. The only gap is vague 'validated' wording, but the tool is simple enough that an agent can invoke it correctly with the given information.

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 names 'message' and 'optional string metadata', but the schema already provides types and constraints. Calling metadata 'string metadata' is potentially misleading because the schema defines metadata as an object with string values, not a string. This adds little value beyond the schema.

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 uses a specific verb ('echo') and resource ('a validated message and optional string metadata'), making the core function clear. There are no sibling tools to differentiate from, so the lack of distinction is not a flaw. However, 'validated' is slightly ambiguous — it might imply an extra validation step that is actually handled by the schema.

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?

No guidance is given on when to use this tool or what to prefer it over. There are no siblings, but the description still does not state typical scenarios (e.g., debugging, round-trip testing). The intended usage is only implied by the verb 'echo'.

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