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

Goes well beyond the readOnly/idempotent annotations: it discloses the auth requirement, the result ordering (smallest published area that meets the filters), page size (20) and cursor mechanics, the per-row fields (fit reasons, waste_pct, source_url, as_of, stale), and an important exclusion rule (spaces not publishing a filtered figure are dropped). That is real behavioral context an agent cannot get from the structured fields.

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?

Dense but front-loaded: the prerequisite opens the description, then filters, then ordering/pagination, then row shape. Every clause carries information, though the long single paragraph packs several distinct concerns (auth, filters, ranking, paging, exclusions) together without separation.

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 must carry the return shape, and it does: row fields, ordering, page size, cursor, and exclusion behavior are all covered, plus the account prerequisite. Nothing an agent needs to call and interpret this correctly 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 coverage is 100%, so the baseline is 3, but the description adds a coupling rule not obvious from the schema: min_capacity applies to only 'one kind' of capacity_kind, and it frames the filters as a size requirement. It also explains that cursor pages are only valid with the same arguments, reinforcing the schema note. Marginally more than the schema alone.

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 (search halls/rooms) scoped to a country with size filters, and the 'best fit first' ranking makes the retrieval intent unambiguous. It separates itself from search_venues/get_venue_spaces by describing the returned unit (spaces/rows) rather than venues. An agent can tell what it returns without opening the schema.

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?

It states the prerequisite (free Messe Atlas account, sign in when prompted) and the implicit use case (find a hall that meets area/height/capacity constraints), but never names an alternative tool or a when-not condition. Usage is inferable from the filter semantics rather than explicitly routed.

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