Installment plans

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

Annotations already declare a safe, idempotent, read-only, open-world call; the description adds substantial non-obvious behavior: plans are fixed credit lines not sized to price, unknown ids yield no plans, Digipay approval is required, and the credit/price interaction at checkout is unconfirmed.

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-loads the core purpose, then layers caveats and routing in short sentences that each carry weight. It is slightly dense with caveats, but nothing is filler or redundant.

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?

With an output schema present, return-value exposition is unnecessary, and the description still covers the interpretive caveats an agent needs (fixed credit line, approval gating, empty result on bad id, unconfirmed checkout combination). Nothing material is missing for correct invocation.

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% and the single product_id parameter is fully documented in the schema (format, example, 'dkp-<id>' origin). The description adds behavioral meaning ('an unknown id gives no plans') but nothing about parameter format beyond what the schema supplies, so the baseline 3 applies.

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?

States a specific verb and resource — 'Get the Digipay credit-line offers available when buying a product' — with the unit (Toman). It clearly distinguishes itself from sibling pricing tools like dk_price_history and dk_product by naming the credit-line semantics.

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?

Explicitly routes the agent to dk_product for the product price and to validate a product id, which is actionable guidance. It does not, however, state when to prefer this over the similarly-named dk_plus_plans sibling, leaving one plausible alternative unaddressed.

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