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

Annotations already indicate readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds a key requirement about disclosing sponsored steps, which is useful compliance context. However, it does not clarify what happens to the generated routine (e.g., whether it is returned, stored, or formatted) beyond the disclosure note, which holds it below a 4.

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 extremely concise: a single purpose sentence followed by a critical requirement. It is front-loaded with the core action and resource, with no filler or redundant phrasing.

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?

The description covers the core purpose and an important compliance requirement. Since an output schema exists, return values need not be described. The parameters are already well-documented in the schema, so the description provides sufficient context for an agent to call the tool correctly. Minor gaps exist around how the routine is structured, but these are not critical given the schema.

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 parameters are adequately documented. The description directly references 'skin type and concerns' which maps to skin_type and concerns, but it adds no additional detail about parameter syntax or interactions. This meets the baseline for high coverage; no extra credit is warranted.

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 clearly states the action ('Build'), the resource ('sponsored skincare routine'), and the tailoring criteria ('skin type and concerns'). This makes the tool's purpose unmistakable and distinct from sibling tools like brand_spotlight or skin_match, which serve different functions.

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 what the tool does (builds a routine) but does not explicitly describe when to use it versus alternatives or when not to use it. However, the purpose is self-evident given the tool name and sibling names, so it meets the threshold for 'clear context, no exclusions'.

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