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

Annotations already declare destructiveHint=true, so the description's job is to name the specific side effect, which it does: the organiser is notified, and declining one occurrence versus a series sends different messages. This adds consequence context beyond the annotation and warns agents not to treat this as a silent calendar change.

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 purpose is front-loaded in the first sentence, and each subsequent paragraph covers one distinct decision: provenance, pass-back, scope, and refusal handling. There is no filler; the bolded scope instruction makes the main branch easy to scan and apply.

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?

Given five parameters, a destructive annotation, and a potentially ambiguous recurring-event case, every call-time decision is covered. The recurring scope edge case is resolved, the notification side effect is stated, and the refusal behavior is addressed; the output schema covers return-value expectations.

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 100%, raising the baseline, but the description goes well beyond the schema: it explains event_id provenance, requires calendar_id from the same result, and gives a precise decision rule for scope based on is_recurring and whether the user named a date. This directly improves invocation correctness.

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?

The first sentence names a specific action and resource: accepts, declines, or tentatively accepts an invitation someone else sent the user. The 'someone else sent' qualifier distinguishes it from create_event/update_event/delete_event, and the rest of the description ties it to a clear invitation-response workflow.

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?

The description gives concrete when-to-use context: use data from get_availability or search_events, pass event_id and calendar_id straight back, and ask about scope only when the user named no date. It does not explicitly enumerate sibling alternatives as the wrong choice, though the warning about removing an invitation without answering implies why delete_event alone is insufficient.

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