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

Annotations mark it non-read-only, non-idempotent and open-world; the description adds genuinely new context beyond that: the listing itself is not modified, output is capped at 10 terms, terms are derived from the listing's own text with the saved draft applied, and the call 'Counts against the daily AI allowance' (a quota/rate-limit disclosure). It does not explicitly reconcile why readOnlyHint=false while the listing is unchanged (quota consumption is the implied side effect), leaving a small gap.

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 tight sentences, front-loaded with the purpose before constraints and quota. Every clause carries information (scope, output cap, non-mutation, capacity, sibling route, cost). Dense but not padded.

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?

With no output schema, the description correctly covers the return shape ('Returns up to 10 terms that fit the Store's rules and aren't in the listing yet') and the key constraints. Combined with 100% schema coverage and annotations, an agent has enough to call it correctly; only the readOnlyHint rationale is left implicit.

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 baseline is 3; the description goes slightly further by explaining the 'language' parameter's role ('one listing language, written in that language'), telling the agent what language the returned terms will be in. It adds meaning but no syntactic detail beyond the schema's own examples.

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?

States a specific verb and resource ('Ideas for Store search terms') scoped to 'one listing language', and immediately distinguishes itself from the sibling that saves them ('the listing isn't changed ... save them with update_listing'). An agent can tell this apart from update_listing or translate_listing_missing without opening any 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?

Gives clear usage context: it produces candidates and the caller then chooses a few and saves them via update_listing, with the listing's 7-term/21-word capacity given as the selection constraint. It names the follow-up sibling but does not state when the tool should NOT be used (e.g. when terms already exist), so it stops short of full when/when-not guidance.

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