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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description adds genuinely useful behavioral context by disclosing the cost ("10 credits"), but says nothing about return format, rate limits, or whether suggestions are live. The credit disclosure earns credit beyond the annotations.

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?

A single front-loaded sentence plus a cost tag; every element earns its place with no padding. Slightly terse but well-structured.

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 simple read-only suggestions endpoint with annotations covering safety and no output schema, the description is adequate but thin. It omits how suggestions are returned and any hint about the sibling amazonSearch, leaving a small gap for correct tool selection.

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 67%, so query and department are documented in the schema; only limit lacks a description. "What a shopper has typed so far" in the schema already conveys the query semantics, and the description adds no parameter detail. 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 resource (Amazon's autocomplete suggestions shown as a shopper types) with the verb implicit in the phrasing. It is understandable on its own, though it does not explicitly differentiate from the sibling amazonSearch, which an agent might reasonably confuse it with.

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?

"Useful for keyword research" implies a use case but gives no explicit when-to-use, when-not-to-use, or named alternative such as amazonSearch for actual result scraping. Usage is suggested rather than prescribed.

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