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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context: the default active-only filter (with ability to include expired/upcoming via active=false) and cursor-based pagination via the 'after' parameter. These details go beyond annotations and help the agent understand default behavior and pagination semantics.

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 a single paragraph that front-loads the main purpose and then enumerates filters and behaviors. Every sentence contributes to understanding, with no fluff or redundancy. It is slightly longer than the two-sentence ideal but remains efficient and 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 search tool with 11 parameters fully described in the schema and read-only annotations, the description covers the essential behavioral aspects: default active filter, pagination, and the ability to include non-active promotions. It does not need to describe return values since no output schema exists, and the filter list in the description aligns with the schema. No critical information is missing for an agent to call the tool correctly.

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 all parameters are already documented in the input schema. The description summarizes the filter options but does not add new meaning beyond what the schema provides. For instance, it mentions 'expiry' but the schema already details expiring_within_days. Thus, it provides a convenient overview but no additional semantic value, aligning with the baseline score of 3.

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 'Search current promotions, coupons, sales, and deals across retailers' — a specific verb, resource, and scope. It clearly differentiates from sibling tools like search_retailer_products, which targets product search. The explicit list of filters further narrows the tool's purpose without ambiguity.

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 provides clear context on when to use the tool (searching promotions) and lists filter options, but it does not explicitly name alternatives or state when not to use it. Since the purpose is unambiguous and the sibling tools are clearly distinct (e.g., product search vs. promotion search), the guidance is sufficient but lacks explicit exclusions.

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