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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds substantial behavior beyond them: a hard cap of 4 results, never including the source event, distance and date windowing, fallback radius logic, ordering rules, an empty-list case, and 404 behavior for hidden/cancelled/unknown slugs.

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?

Every clause earns its place and the result cap is front-loaded, but the core content is delivered as one very long run-on sentence that is harder to parse than necessary. Density is justified by the complexity, though tighter partitioning into sentences would read better.

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 is responsible for return semantics and it does cover them (up to 4 events, ordering, empty-list case). It omits what fields each returned event contains, but for a recommendation-style tool with full behavioral rules this is only a minor gap.

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% for the single 'slug' parameter, so the description must carry the load. It implicitly clarifies that the slug identifies an event (via 'never including the event itself' and the 404-on-unknown-slug rule) but never states the parameter's format or that it is the source event's slug explicitly.

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 title and description state a specific resource and behavior: returning up to 4 upcoming events similar to a given event, mirroring the 'More like this' feature. This is clearly distinguishable from siblings like get_event (single fetch) and list_events (browse/filter), so an agent can select it 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 gives clear context for use ('More like this' on the event page) and fully specifies the matching semantics, which effectively tells the agent what this tool is for. However, it never names an alternative or an explicit when-not condition (e.g. when to prefer list_events or get_event instead), so it falls short of a 5.

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