refinery_credits

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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful context by noting it is a 'Free endpoint' that queries 'upstream ZillAPI', meaning the check likely does not consume credits and reflects an external provider's balance. No contradiction with 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 short sentences, front-loaded with the primary action. The second sentence repeats 'credit balance' but adds the free/upstream context, so the redundancy is minor.

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 read-only balance check with an output schema and full safety annotations, the description is largely sufficient. It could mention output format or usage context, but the missing pieces are small given the tool's simplicity.

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?

With schema description coverage reported as 0%, the description carries the burden for parameter meaning, but it never mentions the response_format parameter or its values. The schema itself documents 'markdown' or 'json', so the gap is partially mitigated, but the tool description adds no parameter-level value.

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 and resource: 'Check remaining ZillAPI credit balance.' It is clear about what the tool does and is distinguishable from siblings like refinery_payment_status, though it does not explicitly name a sibling to exclude.

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?

Usage is implied by the purpose: call it when you need the remaining credit balance. It gives no explicit when-to-use versus alternatives or prerequisites, though none of the sibling tools obviously overlaps with this functionality.

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