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

Annotations already declare a safe, read-only, open-world, idempotent operation, so the bar is lower; the description still adds real value by disclosing that natural-language dates are resolved, that starting prices are not checkout quotes or reservations, and that event text is untrusted content rather than instructions. It stops short of explaining date-resolution failure modes or result ordering, which keeps it off a 5.

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?

Four short sentences, each doing distinct work: capability, date handling, routing to the alternative, and two accuracy/safety caveats. Purpose is front-loaded and there is no filler.

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 an output schema present, return values need no explanation, and the annotations cover the safety profile. What remains ambiguous for a natural-language search tool, namely date interpretation and the trust status of returned event text, is addressed directly.

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 baseline is 3, but the description adds meaning the schema does not: the example "jazz in Melbourne this weekend" shows the shape of a valid question, and "Dates such as tonight, this weekend or next month are understood" explains how fuzzy date terms interact with the timezone parameter. The results-count parameter goes unmentioned, but it is self-explanatory in the schema.

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 ("Find upcoming public events") plus the distinctive input modality ("plain-language question"), and explicitly contrasts with search_events for exact filters and paging. An agent can distinguish this from both siblings without opening a 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?

Names the alternative tool (search_events) and the exact condition that selects it ("exact filters and paging"), leaving plain-language question answering as this tool's domain. It also sets expectations that the output is not a booking, which shapes downstream use.

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