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

Annotations declare read-only and non-destructive, and the description goes well beyond them: `unknown` is explicitly not «no», an unconnected business returns `not_connected`, slots are returned on the business's own clock with `timezone`/`start_at_utc` correspondence, and the default window is the next 7 days. It also reiterates that nothing is booked, ordered or paid, which is exactly the safety context an agent needs for an open-world lookup.

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 the eligibility gate, then product behaviour, then service behaviour, then the safety caveat — a sensible ordering for a branching tool. The closing pointer to server instructions and the listing of separation rules is slightly padded, but every clause carries operational meaning.

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 takes on the return-shape burden, documenting `state`, `slots`, `start_at`, and the `not_connected` case. Minor gaps remain around how many slots come back and what happens when the requested window has no availability.

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 earns above that by explaining that `from`/`to` define the slot window with a 7-day default and that `quantity` is the threshold stock is judged against. It leaves `variant_id` to the schema's own note, so it does not add meaning for every parameter.

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 a specific operation on a specific resource: stock state or booking slots for one business's offering, taken from the business's own connected Shopify/Square. It also distinguishes itself from adjacent siblings by pointing to `book_slot` (which consumes `start_at`) and by scoping itself to cards carrying `live_data`.

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 an explicit entry gate (only when the card shows `live_data`) and an explicit exclusion (results are information-only when the card's `cannot` lists `book`), plus a fallback outcome `not_connected`. It does not name a sibling to use instead when the business is not connected or not live, which keeps it just short of a full when/when-not/alternative statement.

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