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

Despite annotations already declaring a safe read-only, non-open-world operation, the description adds substantive behavioral context: the index scale (1.0 = average, >1.0 above, <1.0 below), that retail events are not pinned to static ISO weeks, and critically that an unavailable result means the curve was never computed rather than zero demand. That last point prevents a serious misinterpretation.

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-loads the definition and scale interpretation, then the two usage modes. Dense but nearly every sentence carries information; the two 'Use without ASIN / Use with ASIN' sentences are slightly parallel but each adds a distinct output shape.

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 shapes need not be enumerated, and the description still covers the things schema cannot: the data threshold required for computation, how to read the index, and what an unavailable result implies. Nothing an agent needs to call it correctly 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 coverage is 100%, so the baseline is 3, but the description goes beyond the schema by explaining the semantic effect of the primary parameter: the presence or absence of ASIN switches between a ranked cross-ASIN summary and a single-ASIN weekly curve. It also reinforces the limit default of 52 for ASIN curves.

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 ('Get a year-independent, unlabeled 52-week ISO-week demand curve for ASINs') with the source basis (historical sales, sessions, revenue). An agent can immediately distinguish this from sales/traffic or ranking siblings 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?

Explicitly separates the two calling modes: without ASIN gives a ranked summary of all ASINs by seasonal amplitude, with ASIN gives the weekly curve plus coverage and availability metadata. It also states the data prerequisite (365 distinct daily records per ASIN). Missing only explicit routing to named sibling tools when seasonality isn't the right lens.

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