Update Event

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

With no annotations, the description carries the full disclosure burden. It usefully discloses partial-update semantics, but omits permission/auth requirements, whether the change is reversible, and whether attendees are notified. It also doesn't surface the destructive replace semantics of the attendees field, though that is captured in the schema.

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?

Two short sentences with the core action and the most important calling convention front-loaded. No 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?

An output schema exists, so return-value explanation is unnecessary, and the schema fully documents all 11 parameters. Still, for a mutation tool with zero annotations, the description should say more about side effects (attendee notifications, replace semantics) and any permission or conflict constraints.

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 every parameter is already documented in the schema, including formats (RFC3339, yyyy-mm-dd) and the attendees-replaces-existing behavior. The description adds no parameter meaning beyond that, so the baseline of 3 applies.

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 ('existing calendar event'), which clearly separates it from create_event, delete_event, and get_event siblings by name. It stops short of explicitly naming an alternative, but the purpose is unambiguous.

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?

'Only provided fields are changed' implies the patch-style usage context and is a meaningful hint about how to call it. However, there is no explicit when-to-use guidance, no mention of prerequisites (e.g., event must exist, which calendar), and no routing to siblings like create_event for new events.

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