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

Annotations only declare readOnlyHint=false, destructiveHint=false, openWorldHint=false. The description adds substantial context beyond that: the URL is one-time, the upload requires the correct Content-Type header, per-file and per-call limits (8 files, 15 MB photos, 50 MB videos), dimension/duration constraints, and that the tool is a no-op for videos unless a custom-footage moment exists. This is rich behavioral disclosure the annotations cannot convey.

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?

The core workflow is front-loaded in the first sentence, and the remaining constraints are organized as a scannable bulleted list with no filler. It is dense and fairly long, but every clause (formats, sizes, tagging, descriptions, file cap) carries operational weight.

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?

There is no output schema, so the description correctly explains the return value (upload_url plus a ready-made curl command) and the required next step. For a 2-parameter upload-initiation tool, nothing an agent needs in order to invoke it correctly appears to be 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 50%: project_id is documented, content_type carries only an enum. The description enumerates the accepted formats (JPEG/PNG/WebP, MP4/MOV), which effectively explains the content_type enum values, but it never clarifies the meaning or scope of project_id or how content_type relates to the uploaded file. Baseline 3 is appropriate since the schema plus enum carries most of the load.

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?

The description states a specific verb and resource ('create media upload' returning a one-time upload_url for a photo or video file on the user's machine) and names the follow-up sibling (finalize_media_upload) and the moment-based sibling (add_moment). An agent can distinguish it from finalize_media_upload and update_product_media without opening any 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?

It states the precondition (a local photo/video file plus an agent that can run curl or make HTTP requests), the exact sequence (PUT bytes with Content-Type, then call finalize_media_upload), and the failure mode for videos uploaded alone ('does nothing' without a custom-footage moment). Explicit when-to-use and what-comes-next guidance is present.

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