getAccountBalance

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

Annotations only supply readOnlyHint/openWorldHint; the description adds real behavioral context the schema cannot: a zero balance does not always halt calls for usage-based billing orgs, and the call requires Billing access with a documented 403 remedy path. This is exactly the kind of non-obvious operational detail that prevents wrong agent conclusions.

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-loaded with what the call returns, then usage timing, then edge cases and auth. Every section earns its place, though the seven-paragraph layout is longer than strictly necessary and could be tightened without losing the 402/403/zero-balance guidance.

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, the description carries the burden of describing the return payload and does so (balance, minutes, plan, concurrency, auto-recharge). Combined with scope, timing, and auth/error handling, an agent has everything needed to call it correctly and interpret results.

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 the schema-based baseline of 4 applies. The description usefully clarifies that the absence of parameters is intentional and scope is fixed to the API key's organization, but there is no parameter syntax to document.

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 ('Read your organization's wallet') and enumerates exactly what the payload contains: balance, minutes at your rates, plan, concurrency headroom, auto-recharge. No sibling tool covers account balance, and the description makes the scope unambiguous.

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?

Gives explicit when-to-use ('before a campaign, or on a schedule') with the rationale (surface low credit here rather than via a 402), and an explicit when-not/alternative ('there is no parameter for reading another account; resellers read a client's figures through the Reseller endpoints').

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