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

Annotations already declare the tool is read-only, idempotent, non-destructive, and open-world, so the safety profile is covered. The description adds the scope of data returned (plan, credit, compute jobs, and builds against limits), which is useful context, but it does not disclose freshness, auth requirements, or return format beyond that content list.

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?

The description is very short and front-loads the purpose, which is good. However, it is a sentence fragment with a trailing ellipsis, suggesting incompleteness rather than a fully structured definition.

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-parameter read tool with annotations covering safety and no output schema, the description is adequate but incomplete. It lists data categories but does not clarify return structure, time range, or how it relates to sibling billing or payment tools.

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 the baseline is 4. The description does not need to explain parameter semantics, and there is no schema detail to supplement.

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 resource (account usage and purchases) and enumerates the key data categories: plan, credit, compute jobs, and builds against limits. It is clear what the tool returns, but it does not explicitly differentiate itself from siblings like account_get or pay_status.

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?

The description offers no guidance on when to use this tool versus alternatives, and it does not state any prerequisites or exclusions. The implied use case is inferable from the name and content, but the description itself provides no routing guidance.

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