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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds the non-obvious behavior that cannot be inferred from annotations: a mandatory two-phase confirmation handshake, the CONFIRMATION_REQUIRED response marker, and the requirement to surface consequences to the user before the destructive step. That is exactly the extra context annotations cannot carry.

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 sentences, zero filler. The core action leads, and the confirmation procedure follows immediately — front-loaded and complete for its length.

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 destructive three-parameter mutation with no output schema, the description covers the risky, non-obvious part (confirmation flow) and the schema covers the identifiers. It does not say what a successful call returns or whether the deletion is reversible/soft-delete, which would fully close the loop.

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% and already documents calendar, eventUid, and confirmToken, so the baseline is 3. The description adds a constraint the schema only implies: the second call must use the SAME arguments, only augmenting with the token — useful for preventing agents from re-deriving arguments on retry.

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+resource ('Delete an event') and narrows scope to 'the user's calendar of one provider', which separates it from unrelated delete_* siblings like delete_team or delete_webhook. It does not explicitly distinguish itself from delete_connection_event, the closest conceptual neighbor, so it stops short of a 5.

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?

It gives clear, actionable operating instructions: first call returns CONFIRMATION_REQUIRED, tell the user, then re-call with the same arguments plus token. It lacks guidance on when to choose this over delete_connection_event or cancel_booking, but the two-step protocol is unusually strong usage guidance.

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