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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds important behavior beyond the annotation: it is a real-time fetch with ~10-40 seconds latency, restricted to 'Amazon marketplaces only,' and capped at 'up to 3 pages per call.' These constraints are not available anywhere else and manage agent expectations.

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?

The description is front-loaded with the core action, then gives example triggers, alternatives, and constraints in a logical order. Every sentence adds a distinct fact—returned fields, latency, alternative tools, marketplace restriction—so nothing feels redundant or wasted.

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 tool with no output schema and six parameters, the description covers the return contents, when to use it, latency, pagination cap, and marketplace scope. An agent has all the information needed to select the tool and invoke it correctly without additional lookups.

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 each of the six parameters is already individually documented in the schema. The description doesn't need to restate them but adds value by imposing a usage limit on the page parameter ('up to 3 pages per call') and reinforcing marketplace scoping, which goes beyond the schema's default-value notes.

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 opens with a specific verb and resource: 'Fetch a LIVE Amazon search-results page (SERP)' and lists the exact data returned (position, ASIN, title, price, rating, badges). It also names the sibling tools it is not (search_products, shopping_search), so an agent can distinguish the tool immediately without opening other definitions.

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?

It explicitly states when to use the tool: 'Use when the user wants CURRENT ranking/visibility' and gives three concrete example queries. It also provides clear exclusions: 'for warehouse keyword search use search_products; for buying advice use shopping_search.' This is direct, actionable routing guidance.

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