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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description needs less safety disclosure. It adds real context beyond the annotations: only the authenticated key is ever described, no other key can be selected, the tool reads no market data, and the credit class is free (0 credits). This meaningfully clarifies behavior without contradicting the annotations.

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 a short, front-loaded paragraph: purpose first, then scope, then sibling routing, then credit class. Each sentence has a distinct purpose. It's slightly redundant in saying both 'reads no market data' and 'never about trade ... commodity', but overall it is tightly written and never wanders.

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?

The tool is simple (one optional parameter, output schema present), and the description fully covers the purpose, the input semantics, scope exclusions, the likely mis-generation of response_format, and the correct sibling alternative. An agent neither false nor has to inspect more than this definition to call the tool correctly.

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?

Schema coverage is 100%, so the baseline is 3. The description adds that response_format is the only input, that it changes verbosity and not scope, and that there is no argument for selecting another key—clarifying the parameter's role beyond the schema's own wording and preventing a likely agent assumption.

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 opens by naming the exact resource ('credit balance and the limits of the API key making the request') and lists concrete fields it reports (credits left, reset time, ceilings, reachable tools). It also explicitly contrasts with the sibling kyrodata_get_data_coverage, so an agent can distinguish the tool without opening schemas.

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 gives an explicit when-to-use (account/credit-limit questions) and when-not-to-use (never for trade, climate, or commodity data), and points directly to the right sibling, kyrodata_get_data_coverage, for data-depth questions. It also warns that response_format cannot change the scope, preventing a common misuse.

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