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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower, and the description adds real context on top: the date-confidence vocabulary ('confirmed by its own site', 'expected', 'when it usually falls'), the travel-advice coverage gap, and the distance computation when from_city is supplied. It stops short of describing result ordering or pagination, but the freshness/confidence semantics are genuinely valuable.

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 information is dense and non-redundant, and the core purpose does lead the (single, sprawling) sentence. But the run-on structure with nested em-dashes, quoted fragments, and semicolon lists is hard to parse, and return-value details are bundled into the same breath as the scope statement rather than separated. It is information-rich but poorly structured.

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 and no nested objects, the description must convey what comes back, and it largely does: dates with confidence labels, what the event is, organiser-named closures, the event's own site, and distance from a departure city. The remaining gap is operational detail such as result limits or ordering, but for a read-only three-optional-filter tool this is close to complete.

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 schema already documents month, place, and from_city as optional filters, and the description's 'in one month, at one place, or all of them' largely restates that. It does add one useful nuance for from_city, that the distance is returned 'in the site's words', but overall it does not extend much beyond the schema. Baseline 3 is correct.

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 opening clause names a concrete resource and its scope: 'The big events that fill a town -- festivals, carnivals, Christmas markets, races -- at the places TravelCharika lists, from this month on for a year.' An agent can tell this returns events, not general activities. However, it never differentiates itself from siblings like activities, where_to_go, or best_months, which a reader must infer from the resource alone.

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?

The description explains the three filtering shapes ('in one month, at one place, or all of them') but gives no when-to-use guidance relative to alternatives, no when-not guidance, and no mention of sibling tools. The only exclusions are coverage facts ('A place under travel advice has none listed'), not usage instructions. An agent has to guess whether this or activities is the right call.

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