Credits and usage

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

No annotations are provided, so the description carries the full burden. It does disclose meaningful behavior about the result scope (a 30-day window, grouped by verdict, plus tier-level pricing), but it never states that this is a read-only, zero-side-effect operation, nor anything about authorization requirements or result freshness.

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?

A single ten-word fragment with no filler, front-loading the primary datum (credit balance) before the secondary breakdowns. Nothing could be removed without losing 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?

With no output schema available, the description usefully enumerates what the caller will receive, which is the key completeness concern for a zero-parameter tool. It stops short of explaining units, formatting, or the exact meaning of 'verdict' categories, but it is adequate for a simple read.

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 tool takes zero parameters, so schema-based parameter semantics are not applicable and the baseline is 4. The description correctly implies a parameterless, global query rather than a per-account filter.

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 names the specific resource (credits) and the exact data returned: credit balance, per-tier pricing, and 30-day usage broken out by verdict. It is a noun phrase rather than a verb+resource, and it does not reference any sibling, but no sibling overlaps this resource so differentiation is not needed.

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?

There is no when-to-use guidance, no stated prerequisites, and no mention of alternatives among the 22 siblings. An agent can infer it is a status lookup, but the description never says under what circumstances to call it (e.g. before sending email, before creating a batch).

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