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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the useful scoping fact that results are limited to the current user's authorized sellers/marketplaces, but says nothing about result size or pagination behaviour for a listing call, and an output schema exists so return shape is not its job.

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?

A single front-loaded sentence listing the returned entities with no filler. It is appropriately sized, though the space saved is not spent on the missing usage routing.

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 a full output schema and complete annotations, most of the burden is already handled elsewhere. What remains missing is the operational context an agent needs: that this is the discovery entry point for seller and marketplace identifiers used by the query_* family.

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 coverage is 100% and the five optional filters are documented in unusual detail in the schema itself. The description restates none of them and adds nothing beyond the implicit 'all sellers for the current user' default, which the sellerId schema text already states. Baseline 3 is the correct ceiling.

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 names the resource concretely (sellers, marketplaces, and the SP/Advertising/active status fields returned) and scopes it to the current user, so an agent knows exactly what this returns. It does not, however, distinguish itself from near-neighbours like get_current_user or discover_capabilities, which an agent could easily confuse it with.

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?

There is no guidance on when to call this versus alternatives such as get_current_user or discover_capabilities. The most useful fact — that this is the tool to resolve sellerId/marketplaceId before calling query_* tools — is absent entirely.

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