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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses a per-business rate limit ('at most once every ten minutes however many of its offerings you open'), the caching semantics (from_cache, checked_at), the failure mode with ok:false and a reason, and that the call is free. It also tells the agent to pass action_url through verbatim with ref=versum, which is operationally important.

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?

Front-loaded with 'Free' and the core behaviour, then proceeds in a logical order: why to call it, rate limit, failure mode, and the action_url handoff. It is dense and a couple of sentences are long, but essentially every clause carries real information.

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 does useful work naming return fields (live_check, from_cache, checked_at, ok, action_url) and the degraded path when no live check is possible. A fuller picture of the overall response shape would close the remaining gap, but an agent has enough to call it correctly.

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?

There is only one parameter and schema coverage is 100%, with the schema already noting it is 'the offering id from search_catalog.' The description adds no further guidance on the id itself; its added value is confined to return fields rather than input semantics, so the baseline 3 holds.

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 clearly: 'One offering in full, with ONE live request to the shop asking for that item's price and stock right now.' The live-check behaviour distinguishes it from a plain catalogue read. It does not, however, distinguish itself from the sibling get_product, which an agent could reasonably confuse it with.

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?

Explicitly says 'Call it before you quote a price to a person: a catalogue read yesterday is yesterday's price,' and explains the fallback when a shop has no single-item endpoint (price list, menu, quote form → ok:false, stored reading stands). What's missing is any mention of when to prefer get_product or search_catalog instead.

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