Account Billing

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered without the description. The description adds that `expand=credits` surfaces credit balance and currency, which is useful, but says nothing about authentication requirements beyond 'authenticated account', rate limits, or what happens with multi-account access.

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?

Front-loads the core purpose in the first sentence, then uses a bolded expandable-fields block and a use-case list. Structure is easy to scan, though the use-case list is somewhat padding for a two-parameter read tool.

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 read-only tool with no output schema, the description covers the main behavior adequately. It is incomplete on the `account` parameter and multi-account handling, which matters for a tool scoped to the 'authenticated account'.

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?

Schema description coverage is 100%, so both parameters are already documented in the schema; the description restates the `expand`/`credits` semantics without adding new syntax or format detail. The `account` parameter is not mentioned at all in the description, so no value is added beyond the schema 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?

States a specific verb and resource: it returns billing information for the authenticated account, and names the expandable `credits` field. It does not differentiate itself from close siblings like get_billing_events, get_usage, or get_pricing, so an agent can't route confidently among them from the text alone.

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 'Common Use Cases' section gives implied context (monitoring credit balance, dashboard display) rather than explicit when-to-use guidance. It never states when to prefer this over get_billing_events or get_usage, which are the obvious alternatives.

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