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

Annotations cover the safety profile (readOnly=false, destructive=false, openWorld=false), and the description adds genuinely non-obvious behavior: a per-call price of $0.01 with no charge on failure, a 5 MB ceiling, and the accepted format list. It falls short of explaining what the returned path looks like, whether re-uploading the same image creates a duplicate (idempotentHint=false is not interpreted), or any auth requirements.

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 short sentences, front-loaded with the action and outcome, then inputs, then constraints, then cost. No filler and each sentence carries distinct 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?

No output schema exists, and the description correctly explains the return value as a path usable in a design or article. Combined with format, size, source options, and pricing, the essentials are present; only the `filename` parameter and duplicate/replace semantics are 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 0%, so the description carries the burden: it clarifies that `url` must be a public https URL (beyond the bare maxLength=2000) and that `data` is the file as base64. However `filename` (maxLength 120) is never mentioned, leaving one of three parameters completely undocumented in both schema and description.

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+resource ("Store an image") with concrete use cases (logo, hero background, article cover) and an explicit return value ("the path to use in the design or an article"), which scopes it to the help center. It never names the confusingly similar siblings (files_upload, google_drive_upload, m365_files_upload, files_upload_link), so an agent must infer the boundary from context alone.

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 implied by "use in the design or an article" and by the format/size constraints, but there is no explicit when-to-use statement and no exclusions. With four other upload tools in the sibling list, the description does not tell the agent which one to pick when a user just says "upload this image."

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