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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond annotations: this is a current per-brand set, not a time series, and an empty result is explanatory rather than retryable.

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?

Purpose is front-loaded in the first two sentences, and the Args block is scannable. Minor redundancy with the schema (repeating 1-365 and 1-200 ranges) costs a little, but nothing is wasted overall.

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?

No output schema exists, and the description does cover the meaningful return behavior (the empty-set `note`). Combined with the effective annotation set, an agent has enough to call this correctly, though the absence of sibling routing leaves a small gap.

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?

With 50% schema coverage, the description compensates well: it explains the semantics of `days` (only opportunities first found in the last N days, omit for current set), `limit`, and the legacy `brand` key compatibility. It omits any mention of the `user_intent` parameter, which the schema documents only thinly.

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+resource (get opportunities) and defines the concept precisely as citation gaps where competitors are cited but the brand is not. However, it never differentiates itself from close siblings like list_opportunity_pool or commit_opportunity, so an agent must infer which opportunity tool to pick.

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?

Gives clear operational context: leave `days` unset for the full current set (what the app shows), and empty results carry a `note` that retrying with different `days`/`limit` won't fix. It does not state when to prefer this over `list_opportunity_pool` or when to hand off to `commit_opportunity`.

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