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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds real behavioral value beyond them: it explains WHAT is destroyed (a Gmail mailbox replaces the whole responder, dropping any existing schedule or restriction) and how Outlook differs (keeps unnamed fields, holds no subject). This is exactly the kind of provider-specific destructive nuance annotations cannot convey.

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, front-loaded with the core on/off action before the provider-specific caveats. Dense but essentially every clause (Gmail replace semantics, Outlook preservation, no subject) earns its place.

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?

An output schema exists so return values need not be explained, and annotations plus the provider-specific destructive details give an agent enough to call this correctly. The main omission is any explicit routing to settings_get_vacation.

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 all four parameters are documented in the schema, so the baseline is 3. The description adds only incidental hints ('holds no subject' touches responseSubject) and otherwise does not clarify parameter behavior beyond the schema.

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 states a specific verb+resource (turn the vacation responder on/off) and clearly identifies the operation. It distinguishes itself semantically from settings_get_vacation without naming it, so an agent gets the intent but must infer the distinction from the verb.

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 only implied: the tradeoff of on vs off is described, but there is no explicit when-to-use guidance and no naming of the sibling settings_get_vacation as the read alternative or of any prerequisites. Adequate but with a clear gap.

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