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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile needs no restating. The description adds one useful behavioral note, that liveness is reported, but says nothing about behavior on an unknown or stale id (empty result vs. error) or about what else "details" contains.

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?

One sentence, front-loaded with the resource and scope, with the identifier provenance and the liveness hint appended in a compact parenthetical. No filler, though the parenthetical does slightly interrupt the main clause.

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 one required parameter, no output schema, and strong annotations, the definition is close to sufficient. The remaining gap is that it never enumerates what the returned details include beyond liveness, and the absence of an output schema means that omission is on the description.

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 0%, so the single parameter offer_id is undocumented in the schema and the description must compensate. It does partly, by establishing that the value is an offer identifier obtained from an earlier result, but it gives no format, validation, or example, leaving the compensation incomplete.

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?

"Details of one offer by its id" is a specific verb-plus-resource statement with singular scope, which contrasts cleanly against siblings like get_store_offers and top_offers_in_category. It stops short of naming those alternatives, so differentiation relies on the reader inferring cardinality from the sibling names.

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?

"(from an earlier result)" is a real usage hint: it tells the agent the id must be harvested from a prior search call rather than composed. There is no explicit when-not or a named alternative for bulk or filtered retrieval, so guidance remains implied.

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