Update Event

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

Goes well past the annotations (destructiveHint=true, idempotentHint=false) by explaining *why* it is consequential: changes are saved immediately with no review dialog, and a recurring event changes the entire series rather than one occurrence. That series-wide side effect is the single most important behavioral fact and is not derivable from the schema or annotations.

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 compact sentences ordered by importance: what it does, how it behaves destructively, then routing to alternatives. Every clause carries information; there is no filler or restatement 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?

For a 12-parameter mutation with no output schema, the description covers the critical risks (immediate save, whole-series propagation) and the identifier source. It stops short of saying whether a single occurrence of a recurring event can be edited at all, which is the one ambiguity an agent might still hit.

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 parameters are already self-documenting (including the null/[] clearing semantics for showAs, reminders, and categories). The description's only parameter-adjacent contribution, that eventId and calendarId come from listEvents, merely restates what the schema fields already say. Baseline 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 plus resource ("Change an existing event in place") and immediately scopes it with "only the fields passed change." It explicitly names the sibling operations it is not (createEvent for new, deleteEvent for removal), so an agent can route correctly 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?

Gives explicit when-to-use (modify an existing event) and names both adjacent alternatives with their conditions: "New event: createEvent; removal: deleteEvent." It also tells the agent where the two keys come from (listEvents), which is the prerequisite for invoking it at all.

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