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

The destructiveHint annotation already marks it as a mutation, but the description adds essential traits: partial-update semantics, a special permission requirement with 403 consequences, inability to delete dates, and the underlying PATCH endpoint. This gives the agent operational context beyond what annotations provide.

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?

Four tight sentences, each earning its place. Key partial-update semantics and date-operation scope are front-loaded before the permission requirement and endpoint reference.

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 complex nested-parameter mutation tool, the description covers the highest-risk gaps: partial updates, authentication/permission requirements, date operation constraints, and endpoint. With no output schema, it correctly focuses on behavioral and usage context rather than return values.

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 baseline is 3. The description still adds value by clarifying that only passed fields are sent and by explicitly stating that date deletion is not exposed, a constraint not spelled out in the schema's oneOf structure.

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?

States a specific verb (update) and resource (an event), then enumerates the exact updatable fields. The action is clearly distinguishable from sibling tools like create_event, get_event, and list_events without opening any 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?

Gives clear context: it is a partial PATCH that only sends passed fields, requires special account permission, and supports CREATE/UPDATE date operations but not deletion. It does not explicitly name alternative tools (e.g., create_event) or when-not-to-use conditions, so it stops just 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.