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

Annotations already mark this as read-only and non-destructive, and the description adds meaningful behavior: the call is free, the remaining figure should be reported first, and there is a mandatory 'Account notice' verbatim output contract. No contradiction with annotations exists.

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 core purpose and each section serves a purpose, especially the output contract. It is somewhat verbose, and the 'How to use' guidance overlaps slightly with the 'Report the remaining figure first' instruction, keeping it from a perfect score.

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?

Even without an output schema, the description specifies the returned balance dimensions and the exact handling of the account-notice case. For a zero-parameter read-only tool, no critical usage or response information 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 are zero parameters, so the schema is already complete. The description adds no parameter-specific semantics but does explain what the call returns and that it is free, which is enough for a parameterless tool.

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 opens with the exact object: 'The caller's AMZScout AI-agents token balance — remaining, used, and limit.' It also clarifies that the call is free. This is clearly distinct from the sibling tools, which are all analysis, search, or recommendation tools.

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 gives explicit triggers: answer token-balance/usage/limit questions and use it 'when a call fails on quota.' It does not list alternatives or exclusions, but for a 0-parameter usage-status tool, the stated use cases are sufficient.

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