get_balance

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

With no annotations, the description must carry behavioral disclosure. It does add real value by revealing that the response contains two distinct figures (total balance and spendable balance), which prevents misinterpretation of the output. However, it says nothing about whether the call is read-only, what permissions are needed, or freshness/caching of the balance figure.

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 compact sentence that front-loads the resource and then qualifies the two balance values. There is no filler or redundant restatement of the tool name.

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 parameterless read tool with an output schema already documenting the return shape, the description covers the essentials: what is fetched and that two balance figures come back. Only minor context, such as read-only nature or account-scoping, is absent, which is acceptable at this complexity.

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 there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. No parameter-level meaning is missing.

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?

Names a specific resource and verb: the current sape.ru account balance. It further distinguishes two quantities ('full' vs 'available for spending'), so the agent knows exactly what is retrieved. It doesn't explicitly contrast with siblings, but none of them (get_user, list_projects, etc.) overlap with balance retrieval, so the gap is minor.

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?

There is no when-to-use or when-not-to-use guidance, no mention of alternatives, and no prerequisites (e.g., authentication or account context). The tool's scope is self-evident from the name, so an agent can infer usage, but the description contributes nothing to that inference.

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