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

Annotations only supply the generic readOnly/openWorld/destructive flags, but the description adds specifics an agent cannot get elsewhere: link lifetime (60 minutes default, up to 24 hours), the constraint that the host computer must be online, that anyone with the link can download, that the file streams through BCD in pieces and is not retained, and the required read permission. No contradiction with 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?

Five short sentences, front-loaded with purpose and the critical output instruction ('Give the user the url'), followed by the expiration/online constraints, the security caveat, and the permission requirement. No sentence is redundant.

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 no output schema, the description correctly tells the agent what to hand back (the URL). It covers durability, availability, security exposure, data handling, and required permissions for a genuinely open-world operation, so nothing essential is missing.

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 coverage is 100%, so the schema already documents path, minutes, and deviceId, including bounds. The description restates the expiry default and ceiling, adding light context for 'minutes,' but does not touch deviceId selection or the 2 GB limit 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 opens with a concrete verb and resource: 'Make a link that downloads one file from a computer,' plus the user-facing purpose (open on phone or pass on). The download direction is inherently distinct from the upload_link sibling, so an agent can route correctly without opening either schema.

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?

It gives clear context (share to a phone or hand off a link) and an explicit guardrail: 'make one only for a file the user asked to share.' It does not, however, name an alternative tool or say what to do when a durable transfer is needed rather than a link.

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