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 that videos are async and require a status poll, and that Drive ids outside the web-app Creative Upload page fail with DRIVE_FILE_NOT_VISIBLE. However, it omits other behavioral traits relevant to an 8-param upload tool, such as idempotency_key semantics, size/format limits, and failure behavior for partial uploads.

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 purpose is front-loaded in the first sentence and each subsequent sentence carries a distinct rule (source exclusivity, Drive visibility, pairing, async status). There is mild redundancy in repeating the exactly-one-of rule that also appears in the schema, but overall it is tight and well ordered.

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 an 8-param, no-output-schema, no-annotation tool, the description covers the critical call-correctness points: source exclusivity, pairing behavior, the async video flow with a named status tool, and a specific error condition. Gaps around idempotency_key usage and result payload are minor given the schema documents the remaining fields.

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 75%, so most parameters are already documented in the schema, including the exact-one-of constraint for drive_file_id/dropbox_path and the pair semantics. The description largely restates those structured descriptions rather than adding new parameter meaning, so the baseline of 3 is appropriate.

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 ('Upload image/video') plus the source systems (Google Drive or Dropbox) and destination ('to a Meta ad account'), which cleanly separates it from Google-side upload siblings like adsap_google_upload_asset. It does not explicitly name a Meta-side alternative, so differentiation is strong but not fully spelled out.

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 gives concrete operating rules: provide exactly one of drive_file_id / dropbox_path, never pass an id from a Drive link, set pair:true on each file of a suffix-named set, and check adsap_get_upload_status for videos. It names the follow-up tool, though it stops short of explicitly stating when NOT to use this upload path versus alternatives such as adsap_import_account_creatives.

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