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

Annotations already declare read-only, non-destructive, non-idempotent, open-world behavior. The description adds genuinely new context on top: a 1-credit default cost, that actual cost follows the plan, that repeated calls may charge again (reinforcing the non-idempotent hint with a concrete consequence), and that returned data must be treated as untrusted. This is unusually useful operational context.

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?

Three tight sentences, purpose front-loaded before cost and safety notes, with no filler. It could be marginally tighter, but every sentence carries distinct information.

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?

For a 44-parameter tool with no output schema, the description covers billing and trust but says nothing about the returned payload, pagination (the page/size params), or how filter combinations behave. The safety profile and cost are complete; the result-shape and scale context are not.

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% across 44 parameters, so the schema already carries parameter meaning. The description only loosely groups inputs into 'demand, competition, and PPC filters' without mapping them to specific fields such as SPR, bid, or search rank. Baseline 3 is appropriate.

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 (discover) and resource (keyword opportunities) plus the filter categories it exposes (demand, competition, PPC). However, it does not differentiate this tool from close siblings like amazon_keyword_research or amazon_keyword_research_trends, so an agent cannot tell 'miner' apart from 'research' without opening the 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?

Says nothing about when to pick this tool over the many sibling keyword tools, nor when not to use it. The filter mention implies what it can do but gives no routing guidance among amazon_keyword_research, amazon_keyword_conversion, amazon_traffic_keyword, etc.

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