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

With readOnlyHint and openWorldHint already present, the bar is lower, but the description adds value by disclosing the response composition (shopping_results fields, category blocks, sponsored listings, refinement chips) and the API key requirement. No contradiction with annotations exists.

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 sentences with no filler. The first sentence front-loads the tool's purpose and output, the second captures the key parameter constraint, and the third states the operational prerequisite. Every sentence earns its place.

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 17-parameter tool with no output schema, the description supplies the essential output shape and the most important parameter-combination constraint, while the schema covers individual parameter details. It could be more complete by explicitly routing the agent to this tool only for shopping queries versus generic search, but the core invocation knowledge is present.

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 82%, so the schema already describes most parameters. The description adds crucial cross-parameter semantics not visible in the schema: the mutual exclusivity of price/sale/shipping/small_business refinements and the rule that sort_by combines with one refinement. This meaningfully improves correct invocation.

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: 'Search Google Shopping'. It then enumerates the concrete return components (product grid, category blocks, sponsored listings, refinement chips), which clearly distinguishes this tool from generic siblings like google_search, bing_search, and google_maps.

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?

The description gives practical usage guidance: it states the API key prerequisite and explains that price bounds, sale, shipping, and small business refinements are mutually exclusive while sort_by can combine with one of them. It does not explicitly say 'for general web results use google_search', so it stops short of full alternative routing.

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