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

The annotations already establish that the tool is read-only, idempotent and non-destructive, yet the description also adds a non-obvious domain fact: 'No shop found' does not mean the name is available, because Etsy never reuses the names of closed shops. That caveat directly affects how an agent interprets the results and cannot be found in any structured field.

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?

Two tight sentences, with the scope stated first and the critical interpretation caveat immediately after it. No filler and no repetition of the title.

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 one-parameter, read-only tool, the description covers the scope and the main interpretation pitfall well. But with no output schema, the description is largely silent about the shape of the results: how rule violations and availability are reported per name, and whether a per-name breakdown comes back.

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 schema already documents the single 'names' parameter, including the maxItems of 6 and the string-or-array union. The description's 'up to 6 shop names' only restates that limit, 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?

It names a specific verb and resource ('Checks ... shop names against Etsy's shop name rules') and states the batch limit of 6. No sibling tool covers this task: fee_calculator, listing_check, niche_check and rank_check all ask different questions, so the agent can choose it without opening another 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?

The usage is only implied: the 6-name cap and the availability framing suggest pre-registration validation, but the description never states when to prefer this tool over the siblings, nor does it set out prerequisites or exclusions. An agent must infer the context from the tool name alone.

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