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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, covering the safety profile. The description adds one useful behavioral trait: the compliance requirement to disclose sponsored steps individually. However, the verb 'Build' sits awkwardly with readOnlyHint=true, implying creation/modification, which creates mild ambiguity about whether the tool mutates state.

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?

Two short sentences with no filler. The purpose is front-loaded and the REQUIRED compliance note is a critical, actionable instruction that earns its place. Slightly more structure (separating purpose from compliance) could help, but it is efficient.

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?

An output schema exists, so return values are covered elsewhere. The description covers purpose and the sponsorship disclosure. However, it omits routing guidance relative to skin_match and sponsored_search, and doesn't clarify how budget_usd or routine_type constrain the generated routine. Adequate but with notable gaps for a 5-parameter generative tool.

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 baseline is 3. The description maps skin_type and concerns to 'tailored to shopper's skin type and concerns,' adding minimal meaning beyond the schema. It adds nothing about budget_usd, routine_type enum semantics, or tenant_id, which are all already documented in the schema.

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+resource: 'Build a sponsored skincare routine tailored to shopper's skin type and concerns.' This is clear and actionable. However, it does not explicitly differentiate itself from overlapping siblings like skin_match and sponsored_search, which share the skin-topic/sponsorship space.

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?

No usage guidance is provided. There is no statement of when to use this tool versus alternatives such as skin_match (which likely handles skin-type matching) or sponsored_search. No exclusions, prerequisites, or when-not-to-use conditions are given.

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