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

With no annotations, the description carries the full burden of behavioral disclosure. It usefully states that it will explicitly mark missing/estimated conditions and that it will not fabricate real-time prices. It does not mention other behavioral traits such as data mutation, authentication requirements, or error behavior for invalid input combinations, but for a calculation tool the disclosed constraints are meaningful.

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?

Two sentences with no redundancy. The core action, input scope, and key limitation are front-loaded and every clause adds information. It is appropriately sized for the complexity it addresses.

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 has a large nested deal object, four top-level parameters, and no output schema or annotations, yet the description is only two sentences. It does not specify the return value format, how horizonMonths is applied, which conditions are considered missing/estimated, or how the total cost is composed (fees, installments, etc.). For this complexity, the description is incomplete.

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 description coverage is 0%, so the description must compensate. It names a few broad input categories (device price, plan hold period, add-ons, confirmed discounts) that map to some fields, but the actual schema is large and nested with fields like subsidy_type, mandatory_costs, installment_months, and selection_discount_policy. The description does not explain these or their roles, so it only partially compensates for the missing schema descriptions.

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 states a specific verb ('계산합니다' – calculates) and resource ('12~36개월 총비용' – total cost over 12–36 months), and names the key inputs: device price, plan hold period, add-ons, and confirmed discounts. The clause 'does not create real-time sale prices' helps distinguish it from search/deal sibling tools. This is clear and specific, not a tautology.

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?

The description gives clear context that this tool computes total cost from user-provided deal data and explicitly says it does not produce real-time sale prices, which offers some negative guidance. However, it never names sibling alternatives (e.g., calculate_contract_penalty) or states conditions for choosing between them, so usage guidance remains implied rather than explicit.

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