不動産情報サービス MCP

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

Annotations already declare this as a safe read-only operation (readOnlyHint=true, destructiveHint=false). The description adds valuable context beyond annotations by specifying the date-fns formatting library requirement and the 24-hour notation convention ('HH'), which helps the agent understand behavioral constraints not captured in structured fields.

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?

The description is perfectly concise with two sentences that each earn their place. The first sentence states the core purpose, the second provides essential formatting details with practical examples. No wasted words, front-loaded with the main functionality.

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 simple read-only tool with full parameter documentation and clear annotations, the description is nearly complete. It explains what the tool does, how to format output, and references the required library. The only minor gap is lack of explicit return value description, but with no output schema, this would be helpful.

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?

With 100% schema description coverage, the input schema already fully documents both parameters (timezone and formatStr). The description reinforces the date-fns format requirement and provides concrete examples ('yyyy-MM-dd HH:mm:ss'), but doesn't add significant semantic meaning beyond what the schema provides.

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 the specific action ('get current time'), resource ('specified timezone'), and scope ('format string using date-fns format'). It distinguishes itself from sibling tools (city-list, real-estate-price) by focusing on time retrieval rather than data listing.

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 provides clear context about when to use this tool (to get current time with specific formatting), but doesn't explicitly mention when not to use it or alternatives. It doesn't reference sibling tools, but they serve completely different purposes, making differentiation obvious.

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

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, indicating this is a safe, read-only operation with open-world data. The description adds minimal behavioral context beyond this—it mentions the data source (国土交通省の不動産情報ライブラリ) and that it retrieves a list, but doesn't specify details like response format, pagination, rate limits, or authentication needs. With annotations covering key safety aspects, the description provides some value but lacks rich behavioral disclosure.

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?

The description is concise and front-loaded, consisting of two sentences that directly state the tool's purpose and key input requirement. There's no unnecessary information, and each sentence contributes to understanding the tool's function. However, it could be slightly more structured by explicitly separating purpose from usage notes.

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?

Given the tool's low complexity (2 parameters, no nested objects), high schema coverage (100%), presence of annotations, and an output schema (implied by context signals), the description is reasonably complete. It covers the basic purpose and input context, and with structured data handling details, no major gaps exist for a simple retrieval tool. However, it could benefit from more explicit behavioral details like data freshness or error handling.

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 100%, with detailed descriptions for both parameters (e.g., 'area' includes a full code mapping, 'language' explains enum values). The description adds little beyond this, only mentioning that '都道府県コードを指定して検索します' (search by specifying prefecture code), which is already implied by the schema. Since the schema does the heavy lifting, the baseline score of 3 is appropriate, as the description doesn't significantly enhance parameter understanding.

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 the tool's purpose: '取得します' (get/retrieve) a '市区町村一覧' (city list) from a specific source (国土交通省の不動産情報ライブラリ) for a given prefecture. It specifies the verb (取得/retrieve), resource (市区町村一覧/city list), and scope (都道府県内/in prefecture). However, it doesn't explicitly differentiate from sibling tools like 'get-time' or 'reinfolib-real-estate-price', which have different functions.

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 implies usage context by stating '都道府県コードを指定して検索します' (search by specifying prefecture code), which suggests this tool is for retrieving city lists when you have a prefecture code. However, it doesn't provide explicit guidance on when to use this tool versus alternatives (e.g., when to use 'reinfolib-real-estate-price' instead), nor does it mention any prerequisites or exclusions beyond the required parameter.

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

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

Annotations already provide readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the agent knows this is a safe, read-only operation that may return incomplete data. The description adds value by specifying the data source (国土交通省の不動産情報ライブラリ) and clarifying that it retrieves both transaction and contract prices, which provides useful context beyond the annotations. However, it doesn't mention rate limits, authentication requirements, or pagination behavior.

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?

The description is appropriately concise with two sentences that efficiently communicate the tool's purpose and search capabilities. It's front-loaded with the core functionality and avoids unnecessary elaboration. Every sentence earns its place by providing essential information about what the tool does and what parameters it accepts.

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?

Given that annotations cover the safety profile (read-only, non-destructive), the schema provides 100% parameter documentation, and an output schema exists, the description provides adequate context. It specifies the data source, type of price information retrieved, and searchable parameters. For a read-only data retrieval tool with good structured documentation, this description is reasonably 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?

With 100% schema description coverage, the input schema already provides comprehensive documentation for all 8 parameters including patterns, enums, and descriptions. The description mentions that parameters like transaction period, region, and station can be specified for searching, which aligns with the schema but doesn't add significant semantic value beyond what's already documented. The baseline of 3 is appropriate when the schema does the heavy lifting.

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 the tool's purpose: '不動産価格（取引価格・成約価格）情報を取得します' (retrieves real estate price information). It specifies the data source (国土交通省の不動産情報ライブラリ) and the type of information (transaction/contract prices). However, it doesn't explicitly differentiate from sibling tools like 'reinfolib-city-list' which likely provides city lists rather than price data.

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 provides some usage context by mentioning searchable parameters like transaction period, region, and station, which implies when this tool would be appropriate. However, it doesn't explicitly state when to use this tool versus alternatives or mention any prerequisites or exclusions. The guidance is 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.