update_calendar_event

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

With no annotations, the description carries the full burden and does so well: it discloses the side effect of resetting every attendee's RSVP to 'needs-action', the duration-preservation rule when moving `start`, and the no-duplicate guarantee. These are exactly the mutation traits an agent needs before acting.

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?

Tight and front-loaded: the core action and the partial-update rule lead, followed by edge-case behavior and the routing hint. Every sentence conveys a distinct fact 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 10-param mutation tool with no annotations and no output schema, the behavioral coverage is strong, but parameter-level completeness is thin (no format hints for address/timezone, no distinction between message and description). Slightly short of fully self-sufficient.

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 0% across 10 params, so the description must compensate. It adds strong semantics for the time fields (empty = unchanged, moving start keeps duration) but says nothing about address, timezone, message vs description, location, or event_id. Half the parameters remain opaque.

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?

Specific verb+resource ('Change a meeting this inbox organized') with the ownership scope made explicit. It clearly distinguishes itself from create_calendar_event, cancel_calendar_event and rsvp_to_invite, the latter by name. An agent can select it 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?

Explicit when-not guidance: received invitations 'cannot be changed here; answer those with rsvp_to_invite.' It also states the partial-update contract ('Pass only what changes, empty = unchanged'), which tells the agent exactly how to call it versus a full-replace alternative.

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