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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds that results come 'with domain-expert scoring' and 'checkout URLs', but discloses no auth requirements, rate limits, or latency, so it contributes only modestly beyond the structured fields.

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 tight sentences that front-load the core purpose before the usage triggers and return note. No filler, though it is slightly terse for a tool with four parameters and a long sibling list.

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?

With no output schema, the description usefully notes the return shape ('scored products with checkout URLs'), and usage triggers are given for the single required parameter. The main gap is the absence of any routing distinction from skincare_recommend, given the crowded sibling set.

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 brand, query, domain, and strategy are all documented in the schema (including domain auto-detection from merchant). The description adds nothing about parameter syntax, formats, or interactions, so the baseline 3 applies.

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?

States a specific verb (recommend) and resource (personalized products) plus a differentiating qualifier ('domain-expert scoring'). However, it never distinguishes itself from the overlapping sibling skincare_recommend, so an agent cannot fully disambiguate the two from the description alone.

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?

Gives concrete usage triggers ('user wants advice, has a concern, or asks what to buy'), which is clear context for invocation. It stops short of naming alternatives such as compare_products or search_products or stating when not to use it, so routing between siblings is left partly to inference.

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