Get Balance

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the description is not required to establish safety. It does add genuinely non-schema behavior: the balance is denominated in cents as an integer with a parallel display string, and it explains the side-effect-free but decision-critical role of the value in the purchase flow. It stops short of stating auth prerequisites or refresh/staleness behavior, so it is strong but not exhaustive.

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 the purpose and return format in the first two sentences, with the routing guidance after. The final sentence about the card-less fallback and the top-up branch is dense and slightly run-on, but each clause corresponds to a real decision the agent must make, so nothing is decorative padding.

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 zero-parameter read with no output schema, the description covers everything an agent needs: what is returned and in what unit, when to call it, and where to route the user when the balance is insufficient. No return-value gap is left open because the description itself supplies the response shape.

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 the baseline is 4. The description usefully compensates for the absent output schema by describing the returned fields (integer cents and a human-readable string such as `$12.34`), which is more than the empty input schema conveys.

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 verb and resource ('Get the available account credit balance for the authenticated Porkbun account') and immediately distinguishes it from related sibling operations by scoping it to prepaid credit rather than card charges. The return shape (integer cents plus display string) is stated up front, so an agent knows exactly what this tool produces versus get_auto_topup or get_pricing.

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 an explicit when ('Call it before offering to buy anything'), the reason (purchases are paid from prepaid balance, so this decides whether a registration/renewal/transfer goes through), and named alternatives with conditions: top_up_account_credit when the account has a saved card, get_auto_topup to check whether a card is on file. It even covers the negative case (no card, or agent does not charge cards on the user's behalf) with a concrete fallback URL.

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