update_calendar_event

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

No annotations are supplied, so the description carries the behavioral burden. It usefully discloses that this is a partial update ('only the fields to change') rather than a full replacement, but says nothing about permissions, reversibility, attendee notification side effects, or rate limits.

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 single sentence is front-loaded with the purpose and then gives the key calling instruction; no words are wasted. Its brevity is appropriate, though it contributes to the missing behavioral detail noted elsewhere.

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 12-parameter mutation with no annotations and no output schema, the description covers the core invocation but omits side effects and permissions. It is minimally adequate when combined with the 58% schema descriptions, but not fully complete for the tool's complexity.

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 58%, so several parameters are undocumented in the schema. The description adds the partial-update rule for optional fields and names event_id, but does not explain semantics for title, all_day, location, description, or event_id beyond what is obvious.

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 mutation ('Change') on a specific resource ('an existing event'), and 'existing' distinguishes it from create_calendar_event. An agent can identify this as an update operation without opening the 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 states the precondition ('existing event') and the invocation pattern ('give event_id and only the fields to change'), making partial updates clear. It does not name alternatives such as create_calendar_event for new events or find_calendar_events for locating an event, so it falls short of a full when-to-use guide.

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