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

Beyond the readOnly/idempotent annotations, it discloses that the call itself is free (no credit consumption), the meaning of the status enum, the reset boundary (user's local midnight), and how packs are added. It doesn't state caching/freshness of the counter, which is the one remaining behavioral unknown.

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 cost fact ("Free.") before the payload. The middle sentence is dense with enumerated fields but every element is actionable information.

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 zero-arg read with a full output schema and complete annotations, this covers purpose, timing, and the low-credit follow-up. The return-field enumeration is partly redundant with the output schema but reinforces what an agent should surface to the user.

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?

Zero parameters, so there is nothing for the description to disambiguate and the baseline is 4. The description correctly spends no words on arguments.

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?

Names a specific resource (this agent's Gogi credits) and enumerates exactly what comes back: used, limit, remaining, status, reset time, and top-up instructions. No sibling tool touches credits, so there is no ambiguity to resolve.

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?

"Check before long or expensive runs; tell the user when low" gives a concrete triggering condition and a follow-up action. There are no competing tools to exclude, so the absence of a "when not to use" clause is minor.

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