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

With annotations already covering read-only, idempotent, non-destructive, and non-open-world safety traits, the description adds substantial behavioral context: matching order, up to 25 returned stores, what fields come back, and what happens when no match is found. This goes well beyond the structured annotation data.

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 primary use case, then covers matching, returns, parameter guidance, fallback, and exclusions without wasted sentences. Despite its length, every sentence supports routing or invocation.

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 the tool has three optional parameters, full schema coverage, annotations, an output schema, and multiple siblings, the description supplies the missing decision context: when to use it, when not to, and how results behave. Nothing critical for correct invocation appears absent.

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 schema already documents limit, query, and category. The description reinforces that query, category, or both may be supplied and gives category-inference examples, but it adds little parameter syntax or constraint detail beyond the schema, matching the baseline for high schema coverage.

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 states a specific verb and resource: searching stores for coupon codes by product or category rather than a named store. It explicitly distinguishes this tool from siblings find_coupons and list_largest_discounts, so an agent can route correctly without opening schemas.

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 gives explicit when-to-use conditions, concrete example queries, and clear when-not-to-use guidance with named alternatives. The fallback behavior when nothing matches is also stated, leaving little to inference.

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