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

Beyond the destructiveHint annotation, the description discloses that date deletion is not exposed, that unspecified fields are left untouched, that a special account permission is required (403 otherwise), and the underlying PATCH endpoint. These are meaningful behavioral and authorization traits an agent cannot get from the annotations alone.

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?

Information is front-loaded: the field list leads, the date-operation caveat and partial-update rule follow, and the permission requirement and endpoint close it. Every sentence carries load 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?

For a 9-parameter tool with deep nested objects, this is close to complete: it covers mutation scope, date-op limits, partial-update semantics, and authorization. The only minor gap is no explicit guidance on the override_location/regional storage behavior implied by the schema.

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 documents each field and nested structure in detail; the description reinforces this by listing the updateable field set. It adds the useful constraint that date operations are limited to CREATE/UPDATE, but the per-field meaning remains schema-driven.

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 verb (Update) and resource (an event) and enumerates exactly which fields are touched: name, description, timezone, location, keywords, classification, and dates. This is enough to distinguish it from sibling create_event/get_event 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?

It clarifies the date-operation semantics (CREATE and UPDATE, no delete) and that only passed fields are sent, which implicitly signals a partial-update pattern. However, it never explicitly states when to reach for this tool versus create_event, get_event, or list_events, leaving sibling routing to inference.

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