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

With no annotations provided, the description carries the full burden of behavior disclosure. It reveals that the tool returns the authenticated user's balance (implying auth requirement) and details the unlimited credits case via hasUnlimitedCredits. It also clarifies the meaning of the two currencies, providing valuable context beyond a plain 'get balance'. However, it does not mention response format or error conditions.

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 well-structured, opening with a concise statement of purpose and using markdown bullets to clearly separate the two currencies. It is moderately long but every sentence contributes valuable semantic detail without redundancy. The front-loaded core purpose allows an agent to quickly grasp the tool's function.

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?

Given the absence of an output schema, the description compensates by explaining the meaning of credits and tokens, the unlimited credits scenario, and pointing to a separate endpoint for pricing. It does not detail the exact JSON response structure or error behavior, but for a simple zero-parameter balance check, it is reasonably complete and actionable.

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 has zero parameters and schema coverage is 100% (empty schema). The description adds meaning by interpreting the response semantics (credits vs tokens), which helps the agent understand the output. No parameter documentation is needed since there are none, matching the baseline for 0 params.

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 clearly states the tool's purpose: 'Get user balance (guide credits + AI tokens)' and explains it returns the authenticated user's full balance. It distinguishes the two currencies and differentiates from sibling tools like get_credit_ledger or get_tokens_usage by focusing on the aggregate balance.

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 provides implied usage context by explaining when credits vs tokens matter (blocking new guides vs AI features), but it does not explicitly name alternative tools or state when to use this tool instead of them. It references /api/v1/tokens-usage for pricing, but absence of direct alternative guidance leaves room for improvement.

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