get_credits

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

Discloses key traits: 'Free — no credits charged', indicating no cost or destructive effects. With no annotations provided, the description adequately covers the tool's safe, read-only behavior, though it could mention what happens if no API key is provided.

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 wasted words. The action is front-loaded, and every sentence adds value: first states purpose and cost, second provides usage context.

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 0-parameter tool with no output schema, the description fully covers what the agent needs to know: what it returns, that it's free, and when to use it. Minor improvement would be explaining the output format or success indicator.

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 zero parameters, the schema coverage is 100% and no description of parameters is needed. The description adds no parameter specifics, which is appropriate given the baseline.

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 'Get' and resource 'current Fox Credit balance', clearly stating what the tool does. It distinguishes itself from sibling tools like verify_email and find_email by focusing on credit balance retrieval.

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?

Explicitly advises using it 'before a big verify/find run' and provides credit costs for operations (verify=1 credit/email, find=10 credits/contact), guiding the agent on when to use this tool versus alternatives.

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