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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: the public catalogue source, the 50-result maximum, and the dataAsOf timestamp. It doesn't discuss errors or pagination, but those are secondary given the annotations and output schema.

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?

The description is compact and well-structured: one scoping sentence, one filter sentence, one constraint sentence, and one result-shape sentence. It is front-loaded with the core purpose, and every sentence earns its place without filler or redundancy.

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?

Covers the data source, all filter modes, the radius dependency constraint, the maximum result count, and the shape of each hit. With an output schema present and annotations providing the read-only/idempotent safety profile, nothing essential 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 0%, so the description carries the parameter-meaning burden. It clarifies that city accepts a name or PLZ, query is free text, dateFrom/dateTo form a date range, and radius requires lat, lng, and radiusKm together with a 100 km max. The limit parameter isn't explicitly explained, but the 50-result cap plus the schema's min/max/default make it recoverable.

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 precise verb and object: search German flea markets from the public my-flohmarkt.de catalogue, and even enumerates the market type synonyms. The filter list and output description make it distinct from sibling tools get_event and recently_updated_events even though those aren't named.

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 clear context for when to use the tool: free-text search, city/PLZ search, date-range search, or radius search. It also explicitly states that radius searches require lat, lng, and radiusKm together, which is key operational guidance. It stops short of a 5 because it doesn't explicitly contrast with the sibling tools, e.g., 'for a known event, use get_event.'

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