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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered. The description adds real behavioral context beyond that: result ordering (nearest first, or soonest sessions first when no place is supplied) and the fact that each venue carries its next session date.

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 tight sentences with zero filler. The core purpose leads, and the zero-argument fallback is appended where it is needed rather than buried.

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 carries the return burden and does partially discharge it by stating each venue includes its next session date and that ordering is distance- or date-based. It stops short of describing the shape of the venue record or any pagination/limit behavior beyond the schema, but it is sufficient for correct invocation.

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%, so the parameters are already well documented, and the baseline is 3. The description adds only one piece of meaning beyond the schema — the behavior when no place is given, which explains why all four parameters are optional.

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?

The description gives a specific verb and resource ("Find the Youngster venues"), disambiguates what a venue is ("libraries, community centres"), and scopes it geographically ("in Australia"). It distinguishes itself from list_sessions implicitly by returning venues with a single next session date rather than sessions themselves, but it never names the siblings to make the boundary explicit.

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 implied by the two modes described (with a place, or with no place), but the description never states when to reach for this tool over list_sessions or book_slot, nor any exclusions or prerequisites. The alternative inputs (latitude/longitude) are only documented in the schema, not surfaced as guidance here.

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