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

readOnlyHint=true already establishes the safe-read profile, so the description's value-add is the returned shape: per-day status values (available/partial/unavailable) and bookable quantity. That is genuinely useful since there is no output schema. It omits pagination, timezone/location scoping behavior, and any rate-limit context.

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, zero filler, with the returned data described first and the API mapping second. Every clause carries information an agent can use.

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?

For a read-only, no-output-schema tool, the description covers scope, return fields, and status vocabulary. It leaves location_id's effect (does it scope the calendar?) and any result-size limits unaddressed, but nothing critical for correct invocation 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% (year, month, quantity threshold, product_id UUID, location_id all documented), so the baseline is 3. The description adds no syntax, format, or constraint detail for any of the five parameters beyond what the schema already states.

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 concrete verb+resource+scope: day-by-day availability for one product over a month, and enumerates what comes back (status, bookable quantity). It implicitly distinguishes itself from the sibling booqable_check_inventory_availability via the calendar/month framing and endpoint mapping, but never names that sibling explicitly.

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?

Usage is only implied through the endpoint hint (GET /api/4/availabilities with subject_type=item), which signals it is the per-item monthly calendar lookup. No when-to-use or when-not-to-use guidance versus booqable_check_inventory_availability or booqable_book_product, which cover adjacent availability concerns.

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