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

Annotations establish it is a non-readonly, non-idempotent, non-destructive mutation. The description adds genuinely useful context beyond those hints: the link expires in one hour, the user must be signed in, and the upload happens manually in the browser, which explains why a human-in-the-loop wait is required.

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?

Front-loaded with the core action, then the usage condition, then the required follow-up sequence. Three sentences with no filler, though the workflow instructions could be trimmed slightly.

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 helpfully names the returned field (uploadPageUrl) and the downstream tool, giving the agent the full call-and-continue loop. It omits expiry/error handling, but the essential lifecycle is covered.

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%, and the enum values (image/video) already carry the format and size limits. The description only restates 'image or video', adding no new semantics beyond the schema, so the baseline 3 applies.

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 (create a one-hour upload link) plus the constrained scope (image or video, uploaded in-browser while signed in). It also names the follow-up sibling, getUploadLink, so the agent can distinguish this 'prepare upload' step from the retrieval step 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?

Explicitly says when to use it ('for any file the user has, including files shared in this chat') and describes the orchestration sequence: share the URL, wait for the user to confirm, then call getUploadLink. It stops short of stating when NOT to use it or naming an alternative path, so not a full 5.

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