naoterumaker/japan-gyousei-data

Administrative Open Data Skill

Access Japanese government open data via the MCP server (mcp.n-3.ai).

Data Sources

#	Name	Purpose	Tool
1	Real Estate Transaction Price	Actual transaction data from the Ministry of Land	reinfolib-real-estate-price, reinfolib-city-list
2	Government Procurement (Bids)	Search for government and local government procurement cases	kkj-search
3	e-Stat	Government statistics portal	e-stat-get-stats-list, e-stat-get-meta-info, e-stat-get-data-catalog

How to Invoke

Use exec with curl. web_fetch is not available because it does not support SSE.

Use the script scripts/mcp-call.sh:

bash <skill_dir>/scripts/mcp-call.sh <data_source> <tool_name> '<arguments_json>'

Examples

# Real estate: Transaction prices in Osaka City
bash scripts/mcp-call.sh reinfo reinfolib-real-estate-price '{"year":"2025","quarter":"3","area":"27","city":"27102"}'

# Real estate: Get list of municipalities
bash scripts/mcp-call.sh reinfo reinfolib-city-list '{"area":"27"}'

# Government procurement: Search for AI-related bids (category 3=Services)
bash scripts/mcp-call.sh kkj kkj-search '{"query":"AI 人工知能","category":"3"}'

# e-Stat: Search statistics list
bash scripts/mcp-call.sh estat e-stat-get-stats-list '{"searchWord":"人口"}'

Tool Details

See references/tools.md for detailed parameters of each tool.

Notes

• Government procurement region filter: kkj-search does not support prefecture parameters. Include a place name in the query string to narrow down results.
• Government procurement details: The MCP only returns a list of search results. Check the original portal site for specifications, amounts, and deadlines.
• Real estate prefecture code: 2-digit code (Tokyo=13, Osaka=27, etc.). Use reinfolib-city-list to get municipality codes.
• e-Stat: First use get-stats-list to identify the statistic ID, then get-meta-info for metadata, and get-data-catalog to retrieve data.
• Rate limits: Use at a reasonable frequency as these are public APIs.