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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the description's burden is lower. It adds valuable behavioral context beyond annotations: authentication requires an Etsy API key via x-api-key (no OAuth), and the tool returns only active listings with no sold-price data. This gives an agent a clear picture of expected behavior and limitations.

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?

Three short sentences and no filler. The core action and scope are front-loaded, followed by the critical auth requirement and the key data limitation. Every sentence 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?

Given the rich 100%-covered schema, the safety annotations, and a clear description, this is nearly complete. The description covers the two biggest contextual gaps: authentication and the active-only/no-sold-price data scope. Since there is no output schema, it might have briefly mentioned response shape, but for a search tool the purpose and limitations are sufficiently clear.

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%, so the baseline is 3. The description adds meaning beyond the schema by documenting the _apiKey parameter and its auth semantics (keystring, x-api-key, no OAuth), which is not present in the schema's properties but appears in the example. This is material because without it an agent would not know how to authenticate.

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 and resource ('Search active Etsy listings site-wide') and names the exact API endpoint (findAllListingsActive). The 'site-wide' scope clearly differentiates it from sibling etsy_search_shop_listings, and the active-listings limitation separates it from any historical or sold-price tool.

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 conveys a clear context: use this for site-wide searches of active Etsy listings, and it notes the limitation that sold-price data is not available. However, it never explicitly names sibling tools or states conditions like 'use etsy_search_shop_listings for shop-scoped queries' or 'use etsy_get_listing for a single listing', so the when-to-use guidance remains implied rather than explicit.

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