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

Annotations already cover safety (readOnlyHint, idempotentHint, destructiveHint false, openWorldHint false), so the bar is lower. The description still adds real behavioral context: results are saved data from the latest review, and video coverage is bounded to the last 7 days. It stops short of describing pagination or how fresh the non-video data is.

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?

Front-loaded with user intent, then the returned fields, then the sibling exclusion. Mostly dense and purposeful, but the trailing fragment "Saved data from the latest review." reads as an orphan and could be merged into the prior sentence.

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?

There is no output schema, so the description carries the burden of explaining returns — and it does so in detail (copy fields, score, issues, video metrics, drop-off, visual review, fix steps). Complete enough to invoke correctly; only minor freshness/pagination detail is 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 description coverage is 100% and the single brand_id parameter is fully documented in the schema (source list_brands, default behavior). The description adds nothing about the parameter, so the baseline 3 for schema-does-the-work applies.

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 and resource — it returns a review of ads already running — and enumerates exactly what the review contains (first line, headline, CTA/link, score, issues, plus video metrics and fix steps). It also names the sibling it is not (get_ad_fatigue), so an agent can distinguish it without opening a 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?

Opens with the concrete user questions it answers ("is my ad copy good?", "why do viewers skip my video?") and explicitly routes the tired-ads case to get_ad_fatigue. Both when-to-use and when-to-use-something-else are given.

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