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

Annotations already carry the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds genuinely useful behavioral context beyond them: conversion is computed from the window's summed units and sessions, and unit-session percentage is called out as the discriminating field. It does not discuss default window fallback or handling of empty windows.

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 what is returned and the source report, and each sentence carries a distinct point. The funnel-separation sentence is somewhat rhetorical but does convey diagnostic value; sizing is appropriate with no major 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?

There is no output schema, so the description must describe returns, and it names the key fields (sessions, page views, conversion rate, unit-session percentage) and their per-ASIN granularity. With zero required parameters and a fully documented schema, this is nearly complete, though it omits default-window and pagination behavior.

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%, so the schema already documents all five parameters including the start_date/end_date vs days interaction and the 730/365-day limits. The description adds no parameter-level meaning beyond that, which is the correct baseline of 3 when the schema does the work.

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: sessions, page views, and conversion rate per ASIN sourced from Amazon's Sales & Traffic report for the connected seller account. This clearly separates it from the get_ads_* siblings, which cover the paid half of the funnel, and from profit/BSR tools.

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 an explicit when-to-use: 'Check it before recommending any listing change', and frames its diagnostic role (distinguishing targeting problems from detail-page problems). It does not name a specific alternative tool or state when not to use it, so it stops short of a 5.

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