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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety and idempotency. The description adds only 'FREE', which is not a behavioral trait. It does not disclose response details, rate limits, or prerequisites beyond what annotations provide.

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 one short sentence that conveys the purpose effectively. However, the redundancy of 'FREE. (FREE)' wastes space without adding value. Still, it is mostly efficient and front-loaded.

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 simple tool with one required parameter and no output schema, the description provides essential context (what is checked) and notes it is free. It lacks details about the return format or possible errors, but given the low complexity and rich annotations, it is minimally adequate.

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% with a clear description for the wallet parameter. The tool's description does not add additional meaning (e.g., format examples or notes) beyond what the schema already states. Baseline of 3 is appropriate given full schema coverage.

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 explicitly states the tool checks 'GCX credit balance, loyalty rewards, and volume tier', providing a clear verb and resource. The sibling tools are diverse and unrelated, so no ambiguity arises. The repeated 'FREE' emphasizes no cost but does not detract from clarity.

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 by stating what it checks and that it's free, but it offers no guidance on when to choose this tool over siblings (e.g., when needing balance vs. asset info). No alternatives or exclusions are mentioned, leaving the agent to infer context.

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