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

Annotations declare readOnlyHint=true and non-destructive, and the description adds that it returns not just a range but also a danger threshold for suspected overcharging, unit info, price trends, and field notes. It also discloses Japan-specific pricing in JPY and mentions regional multipliers when a region is given. It does not detail rate limits or data freshness, but given the annotations cover safety, this is solid.

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?

Bilingual, front-loads the core purpose, then examples, then an English summary and trigger phrases. It is appropriately sized for a tool with detailed return fields, though slightly repetitive between the Japanese and English sections.

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, the description need not explain return values in detail, yet it still summarizes them. It covers purpose, usage context, and regional behavior. Minor gap: no explicit comparison to sibling tools like verify_fair_price, but otherwise complete.

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 schema already describes both the query and region parameters, including the regional multiplier behavior. The description adds no parameter syntax beyond what the schema provides, so baseline 3 is appropriate.

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 clearly states a specific verb (returns) and resource (fair price range for Japanese construction/renovation jobs), naming the exact fields returned (min/avg/max, danger threshold, unit, trend, notes). It distinguishes itself from siblings like verify_fair_price or audit_estimate by being a lookup/reference tool that returns benchmark ranges rather than auditing a specific estimate.

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: use when you want to numerically check whether a construction or renovation cost is fair in Japan, with example categories and trigger phrases. It does not explicitly name alternative sibling tools or say when NOT to use it versus verify_fair_price or check_red_flags, but the context is clear enough.

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