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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real value beyond that: the upstream data source and the meaning of an empty result ('no brand enrolled' vs 'not synced yet'). It stops short of describing pagination or caching/freshness behavior, so not a full 5.

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 sentences, each carrying distinct load: identity/provenance, when to call it, and how to read the empty result. The most decision-relevant constraint (brand-gated work) is front-loaded right after the purpose.

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 read-only, single-optional-parameter tool with no output schema, the description covers purpose, provenance, usage trigger and the ambiguous empty-result case. Nothing an agent needs to invoke it correctly is missing.

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?

There is one optional parameter whose schema description is 100% covered by the schema itself (account seller id, sourced from list_my_accounts, only needed with several accounts). The description adds nothing about the parameter, which is acceptable here since the schema does the heavy lifting.

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 resource (brands registered to this seller in Amazon Brand Registry) plus the extra field of interest (brand entity id) and the provenance (Amazon's Advertising API). It is clearly distinguishable from siblings like get_brand_search_terms or get_ads_overview, which deal with performance data rather than enrollment.

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 an explicit precondition ('Call this before proposing anything brand-gated') and enumerates the dependent features (Sponsored Brands, A+ Content, Brand Analytics, Vine) that require an enrolled brand. It also tells the agent how to interpret the empty case, so there is no ambiguity about when this tool is the right call.

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