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

Annotations already cover read-only, idempotent, non-destructive, and open-world behavior. The description adds valuable context beyond those annotations: it discloses the 'not_measured' state when no capture exists, explains that results are limited to one store and currency per brand, and notes that homepage banners and product markdowns are independent signals. It does not cover rate limits or auth, but against the annotation baseline this is solid disclosure.

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?

The definition is a dense but front-loaded paragraph that immediately states what the tool does, then defines the two readings. Every sentence contributes semantic content. It could be slightly more scannable with structure, but it avoids waste.

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 safety behavior covered by annotations, the description does a good job defining both output readings, the measurement caveat ('not_measured'), and the store/currency constraint. It does not explain the exact response shape or ordering, leaving a small gap, but an agent has enough to invoke the tool 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 50%. The 'days' parameter has only min/max in the schema, but the description adds the default (30) and the 7–365 range, which is useful. The 'domains' parameter is documented in the schema but not mentioned in the description. The description adds some value but does not compensate fully for the half of schema coverage that is missing.

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 states a specific verb and resource: 'How often and how deep each brand discounts, over a window.' The two-metric framing (homepage banner vs product markdowns) makes the tool's purpose distinct. However, it does not explicitly name a sibling tool or contrast itself with one, so it falls short of the top score for sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives. It never mentions sibling tools like get_most_discounted_products or get_active_promotions_and_coupons, nor does it state exclusions or prerequisites. The agent must infer applicability solely from the metric definitions.

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