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

Annotations already cover readOnly/idempotent/non-destructive/closed-world, so the bar is lower. The description still adds real behavioral context beyond them: result ordering, the return fields, the caveat that seat counts are shown as the site displays them (e.g. '5+'), and that session_id chains into start_booking.

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, both front-loaded: the query scope and ordering come first, the routing rule second. No filler or restated name/title.

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 a full schema, an output schema, and rich annotations, the description supplies the missing pieces an agent needs: purpose, ordering, the venue-vs-suburb routing rule, and the downstream session_id link. Only minor operational details like empty-result behavior are absent.

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 every parameter (course, location, limit, date_from, date_to) is already documented with defaults and caps. The description adds no parameter-level syntax or format detail, so the baseline 3 applies.

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 resource (upcoming sessions of one course at one venue), the ordering (soonest first), and the fields returned. It explicitly differentiates itself from search_nearby_sessions by the venue-vs-suburb input distinction.

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?

Names the alternative tool and the exact condition that selects it ('If the person gave a suburb or postcode rather than a venue, use search_nearby_sessions instead'). The agent does not have to infer routing.

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