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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the description's side-effects note adds only mild context: it modifies multiple outbox records rather than a single one. It does not disclose permissions, atomicity, or irreversibility, but it also does not contradict 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?

Every sentence is front-loaded and the whole description is only two lines. It states purpose immediately and adds a deliberate side-effect note; no filler or redundant elaboration. This is a model example of concise tool documentation.

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?

Given the simple two-parameter shape and the presence of a full schema plus output schema, the description is technically entering, but for a bulk mutation it stays silent about partial failures and invalid IDs and what happens to already-sent vs queued faxes. That gap is not fixed by schema, so the description is adequate but not 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 description coverage is 100%, so the baseline is 3. The description merely echoes 'comment' and 'multiple' but adds no extra semantics for payload structure, user_id, or whether IDs must be queued outbox records. It does not fully compensate, but the schema already carries the burden.

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 ('update comment'), a precise resource ('multiple queued outbox faxes'), and the batching mode ('in one request'). The qualifiers 'outbox', 'queued', and 'multiple' distinguish it from sibling tools such as update-outbox-fax and bulk-update-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?

The description does not say when to prefer this tool over alternatives or when not to use it. It never mentions update-outbox-fax for single updates, bulk-update-faxes for non-outbox updates, or any exclusion criteria. The only hint is 'for multiple... in one request,' which is too implicit.

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