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

No annotations exist, so the description carries the burden. It discloses that the call is 'Free' and that it's equivalent to GET /v1/videos/{video_id}/scorecard, which implies a read and gives cost transparency. It does not state auth requirements, whether the api_key is required, rate limits, or error behavior, leaving gaps for a no-annotation 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?

One dense sentence lists the payload contents up front, followed by short clauses for cost and endpoint equivalence. Every fragment carries information; there is no padding.

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?

An output schema exists, so return values needn't be explained, and the endpoint equivalence plus 'Free' note are helpful. However, for a tool with an undocumented api_key and no usage guidance, the description leaves the agent without enough to choose it confidently over video_stats.

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 50%: video_id is documented in the schema as an 11-character YouTube id, but api_key is undocumented there and not explained in the description either. The description adds no parameter-level meaning beyond the schema, 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?

The description names a specific resource (one video) and enumerates what it returns: multiple, views per hour, tags, title/thumbnail changes, reads, similar videos. That distinguishes it concretely from siblings like find_similar or video_stats, though the overlap with video_stats isn't addressed. An agent can tell what it fetches without opening the 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?

There is no guidance on when to pick this over alternatives. The sibling list contains video_stats, trending_shorts, find_similar and channel_outliers, and the description never says how scorecard differs or which to choose. 'Free' is the only hint, and that speaks to cost, not selection.

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