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

Annotations only cover the safety profile (readOnlyHint=false, openWorldHint=true, destructiveHint=false). The description adds genuine non-obvious behavior: it does not fetch bytes and does not persist the signed source URL, which tells the agent about side-effect boundaries the annotations don't 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?

Two dense sentences with the core action and its key constraint front-loaded; the source_url hint is appended second. Minimal waste, though the second sentence is somewhat terse and could clarify the gdrive: format.

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?

With no output schema and no annotation detail, the description does not explain the return contract of a 'prepare' step (presumably a handle/token consumed by google_ads_video_upload_confirm) or the prepare→confirm chaining, which is essential context for calling this correctly.

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 only 14% (just customer_id), leaving six parameters undocumented. The description adds meaning for source_url only (gdrive: selection_key), leaving channel_id, video_title, video_privacy, video_description, and connection_context unexplained, so it fails to compensate for the coverage gap.

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 specific verb (prepare) and resource (one bounded HTTPS video upload), plus the key constraint it does not fetch bytes or persist the signed URL. This distinguishes it from the confirm sibling, though it doesn't explicitly contrast with google_ads_asset_upload_prepare.

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 line 'source_url may also be a gdrive: selection_key from creatives_list_cloud' names a valid alternative source and its originating sibling, which is useful routing. However, there is no explicit when-to-use vs google_ads_video_upload_confirm or the broader prepare/confirm workflow, so guidance remains implied.

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