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

Annotations only supply destructiveHint=true and a title, so the description carries meaningful extra weight. It usefully discloses the side effect that the organizer gets notified and that the action is performed on behalf of the connected account, which goes beyond the annotations. It does not state whether the RSVP is reversible or what happens if the account is not an attendee.

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?

Two tightly written sentences: the core action and its side effect come first, followed by the one conditional detail. No filler or redundancy.

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 four-parameter mutation with no output schema, the description covers the action, the allowed responses, the notification side effect, and the account disambiguation rule. Minor gaps remain around reversibility and error conditions, but an agent has enough to invoke it correctly.

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 all four parameters are already documented in the schema, including the enum values for response_status. The description restates the enum and the account condition without adding new semantics, so the 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 and resource ('RSVP to a Google Calendar event') plus the exact allowed outcomes and the side effect of notifying the organizer. It is clearly distinguishable from siblings like update_event, delete_event, and get_event.

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 a clear conditional usage rule for the `account` parameter ('when more than one calendar-capable account is connected'), which is actionable context. It stops short of naming alternatives or exclusion cases (e.g., when to prefer update_event), so it is clear but not fully routing-aware.

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