get_credit_balance

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

Annotations already include readOnlyHint=true, so the read-only nature is covered. The description adds context about credit costs for other tools, but does not disclose additional behavioral traits of this tool itself, such as whether the balance check consumes credits or how usage is reported.

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 concise and well-structured: the first sentence states the core purpose, and the second provides actionable guidance with cost context. Every sentence earns its place with no unnecessary detail.

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 one optional parameter and no output schema, the description covers the main aspects: what it does and when to call it. However, it omits any explanation of the config parameter and does not clarify whether the balance check itself consumes credits, which are minor but notable gaps.

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 schema has one parameter 'config' with no description and schema coverage is 0%. The description does not mention this parameter at all, leaving the agent without any explanation of its purpose or how to set it. The description fails to compensate for the lack of schema information.

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 'Check your Unilytics credit balance and API usage' with a specific verb and resource. The title 'Check Credit Balance' reinforces the purpose, and it uniquely distinguishes this tool from the many siblings that perform data operations.

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?

It explicitly instructs to call before expensive workflows and provides cost information for data tool calls, noting that discovery tools are free. This gives clear usage context and a when-not (for free tools), though there is no direct alternative tool to compare with.

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