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

The description adds meaningful behavior beyond the annotations: the URL is short-lived, exactly one URL is returned, and access is gated on a clean safety verdict. It does not describe failure behavior when the verdict is not clean, but the disclosed conditional behavior is valuable.

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?

A single sentence carries the core action, the object, and the governing safety condition with no filler. The most important constraint is front-loaded.

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?

The description covers the tool's core contract and safety gate, and an output schema exists so return-value documentation is not required. However, with zero parameter descriptions and no mention of how the required identifiers fit together or what happens when the safety check fails, an agent still has meaningful gaps to resolve before confident invocation.

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 0%, and the description does not explain any of the four required parameters: inbox_id, message_id, attachment_id, and idempotency_key. The reference to 'attachment' hints at attachment_id, but the idempotency_key semantics and the relationship among the three identifiers are left entirely to inference.

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 ('Return'), a concrete resource ('one short-lived Ausca download URL'), and a precise condition ('only when the exact stored attachment has a clean safety verdict'). This clearly distinguishes it from the sibling read/messages/delete tools.

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 'only when the exact stored attachment has a clean safety verdict' gives clear situational guidance for when this tool applies. It does not explicitly name alternatives or exclusion cases, but the uniqueness of the attachment-download purpose makes the usage context evident.

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