Account balance

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

Annotations already comprehensively cover the behavioral profile: readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description adds minimal context beyond 'get the credit balance' and 'authenticated account'. Since the annotations carry the full safety burden, a 3 is appropriate — the description confirms the read-only nature but adds little new behavioral information.

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 sentence with zero waste. Every word earns its place: 'Get' states the operation, 'authenticated' clarifies the account source, 'credit balance' specifies the exact data returned. Nothing could be trimmed without losing meaning.

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-only tool with comprehensive annotations, the description is fully adequate. An agent can confidently invoke this without any missing information. Though no output schema exists, the return value (credit balance) is self-evident from the description.

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?

With zero parameters and 100% schema coverage, the baseline is 4. The description adds the valuable clarification that no parameters are needed because the account is derived from authentication, which preempts any agent confusion about how the account is identified. This is genuinely helpful for a zero-parameter tool.

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 uses a specific verb (Get) and a precise resource ('the authenticated account's credit balance'). It clearly distinguishes this account-oriented tool from the 40+ sibling tools, which are all document-processing operations (parse, redact, classify, summarize). There is zero ambiguity about what this tool does.

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?

While there is no explicit when-to-use or when-not-to-use statement, the purpose is so distinct from all siblings — every other tool operates on documents while this one queries account state — that usage context is unambiguous. The authentication qualifier ('authenticated account') implies it requires an authenticated session, but this is not stated as an explicit prerequisite.

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