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

Adds substantial context beyond the annotations: a 15-minute expiry, byte-level binding via SHA-256 so a different file cannot be attached, the fact that raw bytes are POSTed with the declared MIME type, and that credits are not consumed. These are exactly the operational traits an agent needs before invoking an upload-preparation tool.

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?

Three dense sentences, front-loaded with the capability and its scope, followed by return values and the operational caveats. No filler, and each sentence carries distinct information.

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?

For a six-parameter, all-required tool with an output schema, the description covers the creation semantics, expiry, byte binding, and the handoff to confirmation. Nothing an agent needs in order 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 83%, so the baseline is 3. The description reinforces the binding semantics of contentHash and the role of purpose without contradicting or extending much beyond the schema's own wording (the enum is already explained as never selecting a paid generation).

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 precise verb and resource: creates a signed HTTPS POST upload capability bound to user, project, role, file metadata and SHA-256. It also distinguishes itself from the post-upload step by noting 'attachment status is confirmed separately', which points an agent at studio_media_confirm rather than confusing the two.

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 clear situational context: no file bytes traverse MCP, no generation credits are spent, and confirmation is a separate step. It does not explicitly name when to prefer this over studio_media_upload_widget or studio_media_import_url, so the alternative-choice guidance is implied rather than stated.

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