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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real context beyond them: the empty result is not an error, files live in a draft in the user's Drafts folder, and that draft is auto-removed on attach or swept later. This lifecycle and side-effect disclosure is valuable and consistent 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?

Four sentences, all front-loaded and functional: purpose, ordering, empty-result behavior, then draft lifecycle. Nothing is redundant or padding.

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?

No output schema exists, yet the description explains what comes back (a fileRef per file, or a plain empty notice) and how to interpret it. For a single-parameter read tool, nothing an agent needs to call it correctly 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% and the single uploadId parameter is already documented as coming from create_upload_link, so the schema carries the load. The description only reinforces the ordering relationship with create_upload_link, adding no new syntax or format detail. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Look for the files an upload link put into this mailbox') and the return value ('give back a fileRef for each so you can attach them'). It clearly positions itself relative to the sibling create_upload_link, so an agent can distinguish it 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?

Gives explicit timing ('straight after you upload the file yourself, or once the person says they have') and an explicit anti-pattern ('tell them what you are waiting for rather than calling this repeatedly'). This is exactly the when/when-not guidance the dimension asks for.

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