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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable semantic context by clarifying that the value is 'legacy', not a custodial wallet balance, and not a pricing promise — this goes beyond the structured 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?

Two concise sentences with no fluff. The core purpose is front-loaded, and the caveat is included as a single clarifying clause. Every word adds value.

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 no parameters and an existing output schema, the description only needs to clarify semantics and purpose, which it does. It could be slightly more explicit about the absence of parameters or the nature of the returned metadata, but given the provided structure, it is sufficiently 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 input schema has zero parameters, so there is nothing for the description to add about parameters. With 0 parameters, the baseline is 4, and the description appropriately uses no space on parameter details.

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 uses a specific verb ('Read') and names the exact resource ('account credit/plan metadata'). It also distinguishes this tool from custodial wallet or pricing tools with the caveat, setting it apart from siblings like auraspay_payment_create and auraspay_payment_get.

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 implies usage for reading credit/plan metadata and warns against treating it as a wallet balance or pricing promise. However, it does not explicitly name alternative tools or state when to use them, leaving selection to inference from sibling names.

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