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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is largely covered. The description adds useful context with 'Permanently,' clarifying irreversibility beyond the annotation, but it does not describe return behavior, authorization, or other operational details.

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 description is a single front-loaded sentence with no wasted words. It immediately states the action and the practical reason for using the tool.

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 simple two-parameter delete tool with full schema coverage and descriptive annotations, the description provides enough context to invoke it safely: permanent deletion and quota cleanup. It is not fully complete because it omits any mention of return behavior or recovery implications, though no output schema exists to carry that.

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%, so messageId and operationId are already documented in the input schema. The description does not add parameter-level meaning beyond what the schema provides, which matches the baseline of 3 when schema coverage is high.

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 and resource: 'Permanently delete ... message.' It is clear what the tool does, but it does not explicitly differentiate itself from the sibling archive_message tool.

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 phrase 'to clean up storage and stay within quotas' gives clear context for when to use the tool. It does not explicitly say when not to use it or name archive_message as the non-destructive alternative, so it falls short of full when/when-not guidance.

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