Upload an image from a URL

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

Annotations already declare non-read-only, open-world, non-idempotent, non-destructive. The description adds genuinely new facts the annotations cannot convey: the server performs the fetch, accepted formats, and the 20 MB ceiling — the failure modes an agent would otherwise hit blind. It doesn't mention auth/SSRF restrictions or that repeated calls duplicate the image.

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?

Two sentences, front-loaded with the action and followed by the content constraints, then the usage cue. No filler and nothing an agent would have to re-read.

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 an output schema present and full param coverage, the description need only carry constraints and selection guidance, and it does both. The remaining gap is that it treats this as the only URL-based image ingest path without pointing at upload_image for local files.

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 name, category and description are already documented, giving a baseline of 3. The description only restates the format and size constraints already attached to the url property, adding nothing new; note it says 'https URL' where the schema says 'public http(s) URL'.

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 two-step verb chain (download from URL, upload to Image Label) plus the resource, which an agent can distinguish from upload_image and upload_slide_from_url by the 'from an https URL' qualifier. It never names those siblings explicitly, so the differentiation is inferred rather than stated.

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?

'Use this for images that are online, e.g. ones attached in a chat' gives a clear positive selection condition. It stops short of the inverse rule (e.g. 'for local files use upload_image') or any note that each call creates a new image rather than replacing one.

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