@pipeworx/jma

Connect: https://gateway.pipeworx.io/jma/mcp · Install: one-click buttons

Tools: 4

Japan Meteorological Agency (JMA) weather forecasts, warnings/advisories, and earthquake reports — keyless, sourced straight from JMA’s public bosai JSON feeds.

Tools

• jma_resolve_area(query) — resolve a place name (English romaji or Japanese, e.g. “Tokyo”, “Sapporo”, “大阪”) or a JMA area code to the forecast OFFICE code used by jma_forecast / jma_warnings.
• jma_forecast(area) — 3-day short-term forecast (weather, precipitation probability, temperature) plus 7-day weekly forecast (weather, precipitation probability, forecast reliability, min/max temperature with confidence range), per sub-area. Accepts a place name directly — it resolves internally the same way as jma_resolve_area.
• jma_warnings(area) — current warnings and advisories (警報・注意報) for a region: headline bulletin plus per-area status (issued / continuing / lifted / none in effect) for every JMA warning category (heavy rain, storm, flood, wave, storm surge, dense fog, thunderstorm, avalanche, frost, and their “special warning” / emergency tiers), at both the sub-prefecture and municipality level.
• jma_earthquakes(limit?, min_magnitude?, min_intensity?) — recent earthquakes with magnitude, maximum seismic intensity (JMA’s 10-step 震度 scale), epicenter, and report/occurrence time.

Auth

Keyless. No registration, no API key.

Data sources

• https://www.jma.go.jp/bosai/common/const/area.json — the area master list: 58 forecast offices plus every prefecture/region/city/ward/town JMA itself names, in both Japanese and English. This is what jma_resolve_area walks.
• https://www.jma.go.jp/bosai/forecast/data/forecast/<office>.json — the 3-day + weekly forecast for one office.
• https://www.jma.go.jp/bosai/warning/data/warning/<office>.json — current warnings/advisories for one office.
• https://www.jma.go.jp/bosai/quake/data/list.json — a rolling feed of recent earthquake bulletins (typically the last few weeks), newest first.

Traps for the next person

• Forecasts and warnings are published per forecast OFFICE, not per city. There are 58 offices, roughly one per prefecture plus Hokkaido and Okinawa subdivisions (e.g. Tokyo = 130000). A caller will say “Tokyo” or “Sapporo”, not the office code — every tool that takes area resolves it through area.json’s full hierarchy (office → region → city/ward/town), walking up to the owning office. Some cities resolve unambiguously (“Sapporo City” → office 016000, “Naha City” → office 471000); a name JMA splits into sub-districts (e.g. Yokohama is split into “Northern Yokohama City” / “Southern Yokohama City” in the area master, with no plain “Yokohama City” entry) will not match on the bare city name and needs the fuller JMA-native name or a direct area code.
• area.json’s four levels overlap in code space. A handful of small offices are their own single sub-region, so the same numeric code appears in both offices and class10s (e.g. 011000 Soya). The parent-walk in this pack always walks from the LEVEL you matched at (never by treating a code as globally unique across the four dicts), which is what makes that edge case resolve correctly instead of silently landing on the wrong office.
• weatherCodes is a closed, JMA-published numeric set (three digits, ~110 in active use) — this pack ships a full static translation table (weather_en) built from that fixed set, not a machine translation. The free-text weathers[] narrative (with time modifiers like “後” / “時々” / “一時”) is intentionally left native-Japanese-only: it’s compositional in a way a static table can’t safely cover, and a wrong on-the-fly translation is worse than none.
• Warning codes (the code field inside each area’s warnings[]) are a separate closed numeric set from weather codes (02-49, warnings / advisories / special warnings / emergency warnings). Cross-checked against a live Tokyo response: codes 14/15/16/20 in the areaTypes payload lined up exactly with “強風”, “高波”, “落雷”, “濃霧” in that response’s own headlineText, which is the validation this table was built against.
• Seismic intensity (maxi / int[].maxi) is JMA’s own 10-step 震度 scale: 1,2,3,4,5-,5+,6-,6+,7 — 5-/5+ mean “5 Lower”/“5 Upper”, not “slightly less/more than 5”. An empty string means the bulletin carries no intensity (e.g. a “hypocenter update” record with no shaking report).
• area.json is ~260KB and essentially static (JMA’s forecast-area boundaries are a standing administrative structure) — this pack caches it in module scope for 24h rather than refetching per call.

Tools

• jma_resolve_area — Resolve a Japanese place name (English romaji or Japanese, e.g. “Tokyo”, “Sapporo”, “大阪”) or a JMA area code to the JMA forecast OFFICE code used by jma_forecast and jma_warnings. Sourced from the Jap
• jma_forecast — Weather forecast for a Japanese region from the Japan Meteorological Agency (JMA), covering a 3-day short-term outlook (weather, precipitation probability, temperature per sub-area) and a 7-day weekly
• jma_warnings — Current weather warnings and advisories (警報・注意報) for a Japanese region, from the Japan Meteorological Agency (JMA). Returns the headline bulletin plus per-area status (issued / continuing / lifted / n
• jma_earthquakes — Recent earthquakes reported by the Japan Meteorological Agency (JMA), including magnitude, maximum seismic intensity (震度, JMA’s 10-step scale: 1-4, 5 Lower, 5 Upper, 6 Lower, 6 Upper, 7), epicenter (J