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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower. The description still adds real behavioral context beyond them: prices are counted across currencies without conversion, and search volume is structurally unavailable from Etsy's API. Missing rate/cost or pagination/cap details on volume of listings sampled, which keeps it from a 5.

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 sentences, both earning their place: the first front-loads what comes back, the second pre-empts the obvious wrong expectation. No filler, no restatement 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?

Only two simple non-enum parameters and no output schema, and the description compensates by enumerating return contents in detail. It also closes the biggest gap an agent would hit (no search volume, no demand verdict), so nothing needed to call or interpret the tool is missing.

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 both parameters are already documented in structured form. The description reinforces 'the phrase' and notes non-USD listings are included, which lightly touches the 'physical' filter's intent but never clarifies it. Baseline 3 is appropriate since the schema does the heavy lifting.

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?

Names the resource (facts from one Etsy search) and enumerates the exact outputs: active listing count, price quartiles/median, shared tags and title phrases, and the shops behind them. The output enumeration implicitly separates it from siblings like etsy_tag_ideas (ideas, not observed data) and etsy_shop_audit (shop-level, not phrase-level). No ambiguity about what an agent gets back.

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?

Clearly frames the tool as a raw-facts snapshot and explicitly excludes two expectations: 'No demand or saturation verdict and no search volume.' That negative guidance is genuinely useful. However, it never names an alternative sibling (e.g. etsy_rank_check or etsy_tag_ideas) or states the condition under which an agent should prefer this over them.

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