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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context: the window is evaluated in Riga local time and only events that have started but not ended qualify. It does not touch result ordering or what happens if both city and category are supplied, leaving minor gaps.

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?

A single sentence with the scope front-loaded and the optional filters trailing. Every clause carries information; nothing is padding.

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?

For a three-optional-parameter, annotation-rich, read-only listing tool with no output schema, the description supplies the one thing the structured fields cannot: the exact time-window and timezone semantics. The only shortfall is the absence of output shape or ordering hints, which are minor here.

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 explains city, category and limit thoroughly, including examples and enum-like value lists. The description only echoes that the filters are optional and can be combined; it adds no format or matching nuance (e.g. whether city matching is exact or fuzzy) beyond the schema text.

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 description names the resource (events) and pins a precise scope: on right now, in Latvia, by Riga time, with 'started and not yet ended' defining the window. That is far more specific than the title, but it never contrasts itself with search_events, which an agent could plausibly pick for a time-bounded listing.

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 temporal framing ('on at this moment') implicitly signals when to reach for this tool, and 'optionally in one city or category' shows the filters are not required. However, there is no explicit exclusion or routing statement such as 'for events later today or on a date range, use search_events', so the agent must infer the boundary.

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