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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false; the description adds the missing piece by explaining that "clear" removes the existing answer, which is what the destructive flag refers to. It also discloses the occurrence scoping default (next occurrence), though it says nothing about authorization/participant_token requirements or overwriting an existing answer.

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, zero filler, with the core action and status values front-loaded and the repeating-event nuance and usage trigger following in order of need.

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 five-parameter mutation with no output schema, the description covers what the tool does, the value space, the default occurrence behavior, and the compile-time trigger, and the schema itself handles plan-link validity and credential sourcing. Nothing essential for a correct call is 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 80%, so the schema baseline carries most parameters, but the description still adds meaning: it explains the semantics of the three status values and that occurrence_date defaults to the next occurrence, a default the schema does not state. That is genuine added value over the enum and pattern constraints.

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: recording the participant's RSVP (yes/no/clear) on the plan's Event. That wording conceptually separates it from scheduling-flavored siblings like set_availability, but no sibling is ever named, so differentiation is left implicit.

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 trigger: "Use when the user says they are or are not attending." It supplies no exclusions or alternatives (e.g., when to use set_availability instead), so the agent gets context but not routing help.

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