Epwforge

MCP server for EPWForge — give Claude, Cursor, and other AI agents the ability to generate, morph, and download weather files for building energy simulation.

Status: 0.1.6 (Python). Ten tools — single + batch generation, station fetch, analysis, sensitivity sweep, SVG charts. Production backend, Pro-tier features wired in. Mirrored 1:1 by the hosted MCP at https://epwforge.com/api/mcp (so Claude Web users get the same surface).

What is EPWForge?

EPWForge generates and morphs weather files (.epw, .ddy) for building energy simulation tools — EnergyPlus, OpenStudio, IES VE, eQUEST, and any workflow that consumes EPW. The platform supports:

• TMYx generation anywhere — typical meteorological years synthesized from ERA5 reanalysis for any global lat/lon
• AMY (Actual Meteorological Year) — historical hourly weather for hindcasting and calibration
• CMIP6 climate morphing — apply future-scenario deltas (SSP1-2.6, SSP2-4.5, SSP3-7.0) at 7 warming percentiles. SSP5-8.5 was deprecated per CMIP7 (deemed implausible) — use SSP3-7.0 as the high-end scenario.
• Urban Heat Island adjustment — Stewart & Oke LCZ presets (suburban / urban / dense_urban)
• Extreme event injection — heat waves, cold snaps, humidity events, wind events, with auto-compound blending and per-event intensity (1-10 slider, AR6-auto-fill under SSP)
• Wildfire smoke overlays — CAMS-derived AOD with Beer-Lambert solar attenuation, RH bump, temp shift
• Per-model CMIP6 ensembles — up to 21 morphed EPWs (one per model) for inter-model uncertainty analysis

Tools

Nine MCP tools — generation, station discovery + fetch, analysis, sensitivity sweep, and inline SVG charts:

Tool	Purpose
generate_weather_file	Synthesize an EPW from ERA5 reanalysis at any global lat/lon. Combine basis + SSP + UHI + extreme events + smoke in one call. Default vintage 2011-2025 (recent 15 yr); pick another via tmy_period.
generate_design_day	DDY file for EnergyPlus design-day sizing, computed from the same enriched hourly data.
generate_ensemble	Per-model CMIP6 ensemble — one morphed EPW per climate model (Pro plan).
generate_batch	Generate up to 10 EPWs in parallel into a save_to_dir. Same param shape as generate_weather_file per config. Use for parametric sweeps when you want the actual files (not just deltas — that's compare_scenarios).
find_station	Search the GuzzStations / OneBuilding library for the nearest published TMYx stations. Returns each station's files[] URLs plus agent_guidance so the LLM asks the user "published station or synthesize?" before generating.
get_station_epw	Fetch a published OneBuilding/GuzzStation TMYx file by URL (URL comes from find_station). Returns the .epw (and .ddy when available).
analyze_epw	Download an EPW URL and summarize design conditions, degree-days, GHI, monthly temperature shape. No new generation.
compare_scenarios	Sensitivity sweep — up to 10 scenarios in parallel, returns only design-condition deltas vs baseline (no full EPW content).
chart_diurnal_profile	Inline SVG: monthly Max/Avg/Min hourly profile in °F. Highlights January + July with annual mean overlaid.
chart_compare_scenarios	Inline SVG: horizontal bar chart of cooling/heating/dewpoint deltas. Consumes compare_scenarios's response shape directly.

Most agents will use find_station to discover what's available, then either get_station_epw (for a published TMY) or generate_weather_file (for a custom synthesized one). Reach for analyze_epw / compare_scenarios for quick reads, and chart_* to visualize.

Synthesized vs published — what's the difference?

	generate_weather_file	get_station_epw
Source	ERA5 reanalysis at the exact lat/lon	Published TMYx for a named airport / WMO station
Speed	~10s per call	~1s (cached on the GuzzStations VPS mirror)
Customization	Full SSP / UHI / events / smoke / vintage stack	None — file is what it is
When to use	Custom site, microclimate concerns, future climate, what-if scenarios	Compliance / submittals, reproducibility, comparison to industry baseline
Vintage default	2011-2025 (configurable via tmy_period)	Whatever the published file is — usually TMYx 2007-2021

Quick example

# What an AI agent might call to get a worst-case design weather file:
generate_weather_file(
    lat=40.71,
    lon=-74.01,
    ssp="ssp370",      # SSP3-7.0 emissions (high-end scenario; SSP5-8.5 deprecated per CMIP7)
    year=2090,         # End-of-century
    percentile=90,     # 90th percentile warming
    uhi="urban",       # Stewart-Oke urban LCZ
    events="heatwave,hothumid",  # Auto-compound heat + humidity
    event_duration=14,
    smoke=True,
    smoke_intensity=5,
    save_to="/tmp/nyc_2090_worst_case.epw",
)

Returns {filename, saved_to, bytes_written, scenario, lat, lon, ...} — no inline base64 bloat when save_to is set.

Install

pip install epwforge-mcp

Requires Python ≥ 3.10.

Connecting to Claude / Cursor

Add to your MCP client config (Claude Desktop's claude_desktop_config.json, Cursor's MCP settings, etc.):

{
  "mcpServers": {
    "epwforge": {
      "command": "epwforge-mcp",
      "env": {
        "EPWFORGE_API_KEY": "sk_live_..."
      }
    }
  }
}

Generate an API key at epwforge.com/account.

Plan requirements

Feature	Plan
TMYx / AMY basis (generate_weather_file, generate_design_day without SSP)	Starter
UHI / events / smoke adjustments	Starter
SSP future-climate morphing	Pro
generate_ensemble (per-model CMIP6)	Pro
analyze_epw (parse-only, no generation)	Free (key required)
compare_scenarios	Inherits — each scenario counts as one generation under your tier
find_station / get_station_epw	Free (key required) — pre-computed files, no synthesis cost
chart_diurnal_profile / chart_compare_scenarios	Free (key required) — pure parse + render

Tier enforcement happens at the API; the MCP surfaces 403s as "Plan upgrade required — upgrade at https://epwforge.com/pricing".

Environment variables

Variable	Purpose	Default
EPWFORGE_API_KEY	Bearer token for the EPWForge API	required
EPWFORGE_BASE_URL	Override the API host (mainly for testing)	https://epwforge.com

Behavior notes

• File output: every file-generating tool accepts save_to (or save_to_dir for ensembles). When provided, the EPW is written to disk and the tool returns the path. When omitted, the EPW is returned base64-encoded in the response (≈ 250 KB for a typical year). save_to is recommended to keep agent context lean.
• Compound events: events="heatwave,hothumid" automatically blends hothumid's humidity onto the heatwave at 50%. events="coldsnap,coldwindy" does the same for wind onto a cold snap. The secondary is folded into the primary stitch — not stitched separately.
• Event placement: events are anchored at the cell's hottest day (heat-family) or coldest day (cold-family) and centered for the requested duration. The peak day's diurnal cycle is sustained across the event, producing 30 days of peak heat for a 30-day request — not a stretched 14-day shape.
• Smoke + heat compound: when both are active, smoke aligns to the same anchor day and pads with peak AOD on the heat event's shoulders so solar is fully attenuated across the entire event window.
• AR6 SSP auto-fill: with an SSP scenario active, unspecified event intensities are auto-filled from IPCC AR6 ensemble factors for the cell's region. Cold events stay at intensity 5 (no future amplification) because recent observations (Texas 2021, polar-vortex disruption) don't yet support the AR6 ensemble's cold-side dampening. Pass intensity_auto=false to disable.

Development

git clone https://github.com/guzz-labs/epwforge-mcp
cd epwforge-mcp/python
uv sync
uv run epwforge-mcp  # runs the stdio server

To test against a local API:

EPWFORGE_BASE_URL=http://localhost:3000 \
EPWFORGE_API_KEY=sk_live_... \
uv run epwforge-mcp

Links

• Website: epwforge.com
• API docs / OpenAPI spec: epwforge.com/docs
• Maker: Guzzlabs
• Issues: github.com/guzz-labs/epwforge-mcp/issues

License

MIT