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

Annotations already declare destructiveHint=true, and the description adds the explicit-confirmation requirement, which is useful beyond the structured data. However, 'This is destructive' and 'Side effects: deletes fax record' mostly restate existing information.

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 short and front-loaded with the main action, but the 'Side effects: deletes fax record' line is redundant with the first sentence and adds no informative value.

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?

With an output schema, full param descriptions, and destructive annotations, the tool is largely self-contained. The key gap is scope clarification: it does not specify that this tool deletes a regular fax record as opposed to an outbox fax, which is a real ambiguity given the sibling list.

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 the baseline is 3. The description does not enrich parameter meaning beyond the schema; the confirmation_text constraint is already documented in 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 'Delete a fax record' with a clear verb and resource. It is unambiguous about the primary action, though it does not explicitly distinguish from sibling tools like delete-outbox-fax or bulk-delete-faxes.

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?

No guidance is given on when to use this tool versus alternatives such as delete-outbox-fax or bulk-delete-faxes. The mention of 'requires explicit confirmation' is a prerequisite for invocation, not a selection guideline.

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