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

Annotations already flag destructiveHint=true, but the description adds non-derivable behavior: the deletion cascades to every event, it is irreversible ('not recoverable'), and one calendar class is protected. These are exactly the facts an agent needs before a destructive call and cannot be inferred from the structured fields.

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, front-loaded with the effect, then the constraint, then the confirmation requirement. No filler and nothing buried.

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 destructive tool with no output schema, the description covers effect, irreversibility, and the protected-default constraint. The remaining gap is where calendarId comes from and whether permissions are required, but the core is complete.

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 only 50%: calendarId has no description and the description adds no meaning for either parameter, no format, no source for the ID, no hint that list_outlook_calendars supplies it. The mailbox field's own schema description already covers its guidance, so the description compensates for nothing.

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 ('Delete') and resource ('a calendar') plus the cascade scope ('and every event on it'), which cleanly separates it from delete_outlook_calendar_event in the sibling list. No ambiguity about what gets removed.

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 real precondition ('the default calendar cannot be deleted') and a mandatory pre-call workflow ('Ask the user to confirm before calling this'), which is strong usage guidance. It stops short of naming an alternative tool or stating when another deletion route would be preferable, so not a 5.

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