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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description still earns credit by quantifying the blast radius ('Without eventType every entry on the date goes') and by disclosing remediability ('A day away that is removed can be planned again') — behavior an agent could not read off the annotations.

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 with the destructive scope front-loaded and no filler. The four-item enumeration in the first sentence partially duplicates the enum in the schema, a minor redundancy that keeps it just short of a 5.

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 two-parameter, fully documented schema with rich annotations and no output schema, the definition supplies what matters: scope of deletion, the effect of omitting eventType, and recoverability. Only the relationship to sibling mutation tools is left unstated.

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% and the eventType property already documents 'omit for all', so the schema does the heavy lifting and baseline 3 applies. The description restates the omission consequence in operational terms, which is mildly additive but introduces no new syntax, format, or default information.

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 description opens with a specific verb-plus-resource ('Remove guests, an evening out, days away or a member's absence on one date') and enumerates the event kinds covered, so an agent can tell this is the deletion counterpart to mark_away / mark_eating_out / mark_member_absent. No sibling is named explicitly, which is the only thing separating it from 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?

Usage is implied rather than stated: the agent can infer it should call this to undo an entry on a given date, and the line about omitting eventType acts as an implicit caution to narrow scope. There is no explicit when-to-use versus when-not, and no named alternative (e.g. mark_* tools for adding events) to route against.

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