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

With no annotations, the description carries the full burden. It does well to disclose the two calculation modes and their exact formulas, signalling a pure computation. It omits what happens when the region is unrecognized or has no local currency, and says nothing about the response shape, which matters for an unannotated tool.

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 tight sentences: the first front-loads inputs and output, the second supplies the two formulas. Nothing is repeated and nothing is padded.

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?

There is no output schema and no annotations, so the description should sketch what comes back (real price, implied discount amount, matched region/currency). It explains the math but not the return payload or error behavior, leaving a real gap for a compute tool.

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 both parameters are already fully documented in the schema, including the region-format guidance and the 500–5000 price bound. The description adds no format or constraint detail beyond what the schema provides; 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?

Names a specific verb (계산합니다) and a specific computed quantity (실질 주유가), and states both inputs it consumes (표시 가격, 지역). It does not distinguish itself from siblings like local_currency_for_region, which also concerns regional discount data, so the agent gets no explicit routing help.

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?

Usage is only implied: an agent can infer it should call this when it has a pump price and a region and wants the post-benefit price. There is no statement of when not to use it, no prerequisite that the region must be a recognized local-currency region, and no pointer to list_regions for resolving region strings.

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