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

Annotations already establish readOnlyHint, and the description adds useful behavioral context: the catalogue is 'global,' 'small,' and 'rarely changes,' which helps an agent treat results as stable and cacheable. This goes beyond the bare schema and annotation data.

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 entire description is one compact sentence that defines the tool, states its purpose, and notes its stability. Every clause earns its place and there is no redundant filler or repetition of the title.

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 simple read-only list operation with only optional pagination parameters and full schema documentation, the description is complete. It gives the catalog's role, its relationship to create/update APIs, and its expected size/stability, which is sufficient for correct invocation.

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?

The input schema fully documents `page` and `page_size` with descriptions and bounds, so schema coverage is 100%. The description adds slight contextual value by implying the list is small, but it does not add new parameter-level meaning beyond what the schema already states.

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 a specific resource ('global catalogue of event types') and precisely ties it to the `type` field on `event_create`/`event_update`. This clearly differentiates it from sibling event-related list tools like `event_roles` or `event_presets`.

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 clearly states when this tool is relevant: when needing allowed values for the `type` field on `event_create`/`event_update`. It does not explicitly list exclusions or alternative tools, but the purpose is specific enough for an agent to infer the right context.

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