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

Annotations cover safety (non-destructive, non-idempotent) but say nothing about lifecycle, so the description's key contribution is the 24-hour validity window and the fact that it produces a link rather than performing the upload. That is meaningful behavioral context beyond the annotations; it stops short of saying whether the link is single-use or what happens after expiry.

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?

One sentence, front-loaded with the return value and the 24-hour constraint, with no filler. Everything stated carries information an agent needs.

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 takes on the burden of describing the return value (a secure link, 24h validity). It is nearly complete for a zero-required-parameter tool; the only gap is the post-upload handoff (what to call once the image lands), which matters in a flow with get_upload as a sibling.

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% for the single optional "product" parameter, so the baseline applies. The description adds nothing about what the product reference does to the returned link (e.g. whether it scopes or brands the upload), leaving that entirely to the schema's terse "Optional: product reference".

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?

Specific verb ("Returns") plus a concrete resource ("a secure link ... where the user uploads their own photo, drawing or design"), which is unambiguous about what the call produces. It does not, however, differentiate itself from the closely related sibling get_upload, so an agent must infer which one to call.

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?

Usage is only implied by the phrase "the user uploads their own photo ... from their device" — that hints the tool is for user-supplied images. There is no explicit when-to-use guidance, no statement about which sibling to pick instead (e.g. use_chat_image, get_upload), and no note on what to do after the upload completes.

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