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

The annotations already declare readOnly=true, idempotent=true, and destructive=false. The description adds meaningful behavioral context: the Partner tier requirement, the current signed-out state, the expected authentication challenge, and the instruction not to fabricate an answer. This goes beyond the annotations.

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?

The description is front-loaded with the purpose, followed by the tier requirement, current sign-in state, usage guidance, and a warning. All five sentences are necessary and effectively structured.

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 tool with no output schema and minimal annotations, the description covers the essential usage: what it does, when to call, and what authentication behavior to expect. It doesn't describe the success response, but that's a minor omission given the focus on the auth challenge.

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 and an empty schema, so the description doesn't need to document any. Per the baseline for 0 params, this scores 4.

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 clearly states the tool scans activity for merchants attributed to the user's reseller account, with a specific verb ('Scan') and resource ('activity for merchants'). It distinguishes from siblings by scoping to 'YOUR reseller account' and naming the Partner tier requirement.

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?

It explicitly says to call this tool if the user is asking for their own business, reseller, or licensed data, even though the user is not signed in. It also tells the agent that the server will respond with an authentication challenge, so the agent knows what to expect. No alternative tool is named, but the guidance is clear.

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