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

Annotations already declare non-read-only, non-destructive, open-world, non-idempotent, so the safety profile is covered. The description adds genuinely useful beyond-schema behavior: free/no credit cost, accepted formats, an 80 MB size limit, downstream propagation of the logo flag, and the returned `asset.id`. It does not address duplicate handling despite idempotentHint=false, which keeps it off a 5.

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 and scoped with a compact exclusion; nearly every clause carries distinct information. It is tightly packed with sibling tool names and format/size details in a single dense block, which is efficient but slightly harder to scan than a clean two-sentence split.

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 five-parameter, non-destructive upload tool with no output schema, the description covers formats, size cap, cost, downstream consumption, disambiguation from the sibling, and the return handle. Nothing material an agent needs before calling 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 100%, so baseline is 3, but the description supplies downstream meaning for `primary_logo` ("makes an image the brand's logo, which visuals and films then carry") that the one-line schema text does not, plus URL constraints and return value. It adds real semantic value rather than repeating field text.

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 concrete verb and resource (store an image/logo/video into a brand's Library) and immediately disambiguates from the closest sibling: 'Not upload_asset — that stores into a WEBSITE's media library, which Creative Studio does not read.' An agent can select this over other upload/import tools without opening a 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?

Gives both when-to-use (feeding references into create_visual, add_studio_video_media, create_motion_project `from.asset_id`) and an explicit when-not with the named alternative (upload_asset for website media). It also flags the `primary_logo` special case, so the agent knows the branching condition inside this tool.

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