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

Annotations already declare this as a non-read-only, destructive, open-world mutation. The description adds real value beyond that: it explains that the provider sends the answer from the account's own address, that notify=none suppresses notifying the organiser, and that answering a series cascades to other occurrences and reports a replaced count. The Google message-visibility caveat, however, lives only in the schema, not the description.

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 action is front-loaded, which is good, but the second sentence ('Answering a whole series answers each occurrence answered apart from it too, and says under replaced how many of their answers it replaced') is a convoluted run-on that is hard to parse, hurting readability more than length does.

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 with no output schema, the description covers the important behavioral edges: cascading series answers and the returned 'replaced' count. Combined with the 88%-covered schema, an agent has enough to invoke this correctly, though provider-specific fallbacks (calendarId, provider) are left entirely to the schema.

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 88%, so the schema already documents nearly every parameter including notify, scope, and message semantics. The description largely restates the notify and series behavior rather than extending it, so it does not meaningfully exceed the schema baseline.

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 set (accept, tentatively accept, decline) against a specific resource (an invitation), and the response enum mirrors this exactly. It is clearly distinguishable from siblings like events_edit, events_cancel, or events_create.

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?

Usage is implied by the nature of the tool rather than stated. There is no explicit guidance on when to choose this over events_edit for changing a reply, and no prerequisites are given, though the scope/series and notify clauses give partial context for deciding how to invoke it.

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