check_balance

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

No annotations are provided, so the description carries the full behavioral burden. 'Free to call' adds useful cost/access context, and 'how many credits the account has left' implies a read-only query returning a balance. Still, it does not disclose the exact response format or explicitly confirm there are no side effects.

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 very short sentences with zero filler. The core message is front-loaded and every word contributes to the agent's understanding.

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 trivial zero-parameter tool, the description gives the key fact an agent needs: the tool reports how many credits remain. 'Free to call' adds cost context. A slightly more explicit return format would be nice, but the description is sufficient at this complexity level.

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 the baseline of 4 applies. The description does not need to explain parameter meaning because there is nothing to explain.

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 clearly identifies a credit/balance-checking operation and is easily distinguished from sibling tools like generate_video or check_video. It lacks an explicit imperative verb like 'Get' or 'Inspect', but the meaning is unambiguous.

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?

For a zero-parameter standalone balance check there is no obvious alternative tool, and 'Free to call' signals that cost is not a concern. However, the description does not explicitly state when to use it or whether any authentication is required, leaving some guidance implied rather than stated.

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