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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so safety is partly covered. The description adds nothing beyond the name: it does not state that this call is non-destructive and stages work for a later confirm, nor what artifact or token it produces. For a mutation-prepare tool this is a meaningful gap.

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?

It is a single clean, front-loaded sentence with no filler, which is good. But it is shorter than the operation warrants, so it reads as under-specification rather than disciplined conciseness.

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 a mutation-adjacent prepare step, the description supplies none of the missing context: the confirm follow-up, the expected shape of video_url, or the purpose of connection_context. What the agent needs to call this correctly is largely absent.

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 only 33% (just customer_id documented), so the description is expected to compensate and does not. It never explains that video_url must point at a YouTube video, nor what connection_context is for, leaving two of three parameters undocumented in both places.

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-plus-resource ('Prepare creation of a Google Ads YouTube video asset reference'), so the agent can tell it is the staging half of a two-phase operation. It does not, however, distinguish itself from adjacent prepare tools such as google_ads_video_upload_prepare or google_ads_asset_upload_prepare, which is a real ambiguity in this namespace.

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 description gives no when-to-use context, no mention of the required follow-up google_ads_youtube_asset_confirm call, and no conditions that select it over the other prepare/confirm pairs. The two-phase workflow must be inferred entirely from the '_prepare' suffix.

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