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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds meaningful context beyond those annotations by specifying that results are scoped to what 'this token can access' and by previewing the return payload (marketplaces and currencies), which is especially useful given there is no output schema.

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 with no filler. The verb and core constraint appear immediately, and every remaining phrase ('Amazon seller connections', 'this token can access', 'marketplaces and currencies') contributes essential information.

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 zero-parameter read-only listing tool, the description covers the essential behavior, access scoping, and the main output fields. It could be slightly more explicit about the exact return structure or pagination, but given the tool's simplicity and the readOnly/destructive annotations, it is largely complete.

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?

The tool has zero parameters, so no parameter explanations are required; the baseline for 0-parameter tools is 4. The description's mention of marketplaces and currencies refers to the output, not parameters, and therefore does not need to compensate for any schema gaps.

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 ('List'), a precise resource ('Amazon seller connections'), and the access scope ('this token can access'), plus the returned attributes (marketplaces and currencies). This clearly differentiates it from sibling account_* tools like account_profiles or account_report, which target different account data.

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 no guidance on when to use account_sellers versus alternatives such as account_profiles or account_feedback. There are no exclusions, preconditions, or scenario-based routing hints, leaving the agent to infer usage solely from the tool name and title.

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