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

With no annotations, the description carries the full burden. It usefully discloses the return values (asset_id, media_url) and that media_url is intended for row linking, plus a size ceiling for base64. It does not state permission requirements, whether re-uploading overwrites an existing asset, or failure behavior — meaningful gaps for an unannotated mutation 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?

Two sentences, front-loaded with the action and accepted formats, then the return contract. No filler and nothing duplicated from the schema.

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 compensates by naming exactly what comes back and how it is consumed (asset_id and media_url for row linking). Combined with a fully described five-parameter schema, an agent has enough to call this correctly; the missing pieces are project resolution and overwrite semantics, which are secondary.

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%, so all five parameters are already documented with preference and size guidance. The description adds only the implicit mutual exclusivity of image_url vs image_base64 via 'or', which is baseline-level value when the schema does the heavy lifting.

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 names a specific verb (upload) and resource (PNG/JPEG image) bound to a publisher-scoped AR project, and the accepted formats distinguish it from the sibling upload_publisher_video. It stops short of naming competing siblings like asset_from_drive or upload_project_drive_file, so the differentiation is implicit rather than explicit.

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?

The parenthetical '(image_url or small image_base64)' hints at two input paths and the schema clarifies the size/preference tradeoff, but the description gives no guidance on when this tool is the right choice versus asset_from_drive or upload_project_drive_file. Usage is implied by the publisher-bound scope rather than stated.

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