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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful context that this is a pure data fetch with no AI analysis, going slightly beyond annotations. It does not mention auth or rate limits, but the readOnly annotation covers the primary safety concern. No contradiction.

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?

Four sentences with no filler. The purpose is front-loaded, followed by the no-AI-analysis clarification, the sibling alternative, and a 'How to use' guidance. The guidance is slightly verbose but adds interpretive value, so the structure earns a 4.

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?

Given there is no output schema, the description provides a reasonable summary of return content (per-niche product sets plus aggregates like price/sales/revenue distributions, revenue concentration, brand spread). It also explains how to interpret the data for a verdict, which is helpful for an agent calling the tool.

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 baseline is 3. The description reinforces the keywords count (2–5 niches) and refers to per-niche product sets, which aligns with the count parameter, but it does not add meaning beyond what the schema already provides.

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 clearly states the tool compares 2–5 Amazon niches/category keywords and returns per-niche product sets plus computed aggregates. It explicitly distinguishes itself from compare_products by noting that tool is for ASINs, which helps an agent route correctly.

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?

Provides an explicit alternative for ASINs ('For ASINs, compareProducts is the equivalent') and implies when to use this tool via 'Pure data fetch (no AI analysis) — do the comparison yourself.' This is clear context, though it doesn't enumerate other siblings like analyze_niche for single-niche analysis.

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