update_event

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

With no annotations, the description carries the full burden. It usefully discloses patch semantics, the start/end pairing rule, and the attendee-notification side effect of mutating shared events, but says nothing about permissions, whether unspecified fields are preserved, or how recurring-event instances are affected — a major concern for a calendar mutation.

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?

Three short sentences, front-loaded with the core purpose, then the key constraint, then the risk note. Every sentence earns its place 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 an 8-parameter mutation tool with no annotations, no output schema, and near-zero schema description coverage, the description leaves too much unsaid: recurrence handling, timestamp format, permission requirements, and set-vs-clear semantics for optional fields are all missing.

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 only 13% (just calendar_id is documented), so the description must compensate. Apart from the start/end coupling rule, it adds no meaning for summary, location, description, all_day, or event_id — notably absent are the time format/timezone for start/end and how to clear a field.

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 first sentence names a specific verb and resource ('Partially update one Google Calendar event') and 'partially' signals patch semantics, distinguishing it from create_event and delete_event. It doesn't explicitly name a sibling as its alternative, so it falls short of a 5.

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?

'Supply start and end together' is a genuine usage constraint, and the attendee-notification note flags when extra care is warranted. However, there is no guidance on when to choose this over create_event or respond_to_event, no prerequisites, and no exclusions.

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