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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds useful behavioral scope (only upcoming/ongoing, only public events, no past events), but says nothing about result ordering, pagination behavior, or what happens when filters are combined.

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 front-loaded sentence that states resource, temporal scope, source scope, and filters with 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 four optional params, no output schema, and rich annotations, the description covers everything needed to call the tool correctly. The only gaps are result ordering and pagination, which are minor for a zero-required-param listing tool.

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 50%: `limit` and `online` are documented in-schema, while `city` and `query` are bare. The description compensates partially by mapping 'keyword' to `query` and confirming the `city` and online-only filters, but adds no matching semantics (partial match, case sensitivity, city naming).

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?

Specific verb+resource with scope: 'List upcoming and ongoing public events' and even names the publisher types (NGOs, student clubs, institutions). It is clearly distinguishable from the sibling lists (list_volunteering, list_open_funds, list_stores) by resource alone, though it never explicitly names them.

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 phrase 'optionally filtered by keyword, city or online-only' implies the intended usage contexts, but there is no statement of when to prefer this over `search` or `fetch`, and no exclusions or prerequisites.

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