Open-Meteo MCP Server

Ensemble Forecast

ensemble_forecast

Read-onlyIdempotent

Get ensemble weather forecasts to show forecast uncertainty across multiple model runs. Requires latitude, longitude, and an ensemble model like icon_seamless_eps.

Instructions

Get ensemble forecasts showing forecast uncertainty with multiple model runs. models is required: the ensemble API has no default model (e.g. "icon_seamless_eps", "ncep_gefs_seamless", "ecmwf_ifs025_ensemble").

Input Schema

TableJSON Schema

Name	Required	Description	Default
`tilt`	No	Solar panel tilt in degrees (0 = flat, 90 = vertical); with `azimuth`, sets global_tilted_irradiance.
`daily`	No
`hourly`	No
`models`	Yes	Required: the ensemble API has no default model. Use e.g. "icon_seamless_eps" or "ncep_gefs_seamless".
`azimuth`	No	Solar panel azimuth in degrees (0 = south, -90 = east, 90 = west, ±180 = north); used with `tilt`.
`end_date`	No	Date in YYYY-MM-DD format.
`latitude`	Yes
`timezone`	No	IANA time zone (e.g. "Europe/Paris"), or "auto" for the location's own. Default GMT.
`elevation`	No	Elevation in metres to adjust the values to; defaults to the terrain height at the point.
`longitude`	Yes
`past_days`	No	Days before today to include, in addition to the forecast.
`past_hours`	No	Hours before now to include; alternative to `past_days`.
`start_date`	No	Date in YYYY-MM-DD format.
`timeformat`	No		iso8601
`forecast_days`	No	Days to forecast, starting today.
`cell_selection`	No	Grid cell to use near a coastline: prefer "land", prefer "sea", or the "nearest" cell.
`forecast_hours`	No	Hours to forecast; alternative to `forecast_days`.
`wind_speed_unit`	No		kmh
`temperature_unit`	No		celsius
`precipitation_unit`	No		mm
`temporal_resolution`	No	"native" keeps each model's own time step; "hourly", "hourly_3" and "hourly_6" resample to 1, 3 or 6 hours.

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv2.5.2Oct 3, 2026

changedInput schema / properties / models / anyOf

Previous value: -[
-  {
-    "enum": [
-      "icon_seamless_eps",
-      "icon_global_eps",
-      "icon_eu_eps",
-      "icon_d2_eps",
-      "dwd_icon_seamless_eps",
-      "dwd_icon_global_eps",
-      "dwd_icon_eu_eps",
-      "dwd_icon_d2_eps",
-      "gfs_seamless",
-      "ncep_gefs_seamless",
-      "ncep_gefs025",
-      "ncep_gefs05",
-      "ncep_aigefs025",
-      "ecmwf_ifs025_ensemble",
-      "ecmwf_aifs025_ensemble",
-      "ecmwf_ifs_europe_ensemble",
-      "ecmwf_aifs_europe_ensemble",
-      "gem_global",
-      "gem_global_ensemble",
-      "cmc_gem_geps",
-      "bom_access_global",
-      "bom_access_global_ensemble",
-      "google_weathernext2_ensemble",
-      "ukmo_global_ensemble_20km",
-      "ukmo_uk_ensemble_2km",
-      "meteoswiss_icon_ch1",
-      "meteoswiss_icon_ch2",
-      "meteoswiss_icon_ch1_ensemble",
-      "meteoswiss_icon_ch2_ensemble",
-      "dwd_icon_eps_ensemble_mean_seamless",
-      "dwd_icon_eps_ensemble_mean",
-      "dwd_icon_eu_eps_ensemble_mean",
-      "dwd_icon_d2_eps_ensemble_mean",
-      "ncep_gefs_ensemble_mean_seamless",
-      "ncep_gefs025_ensemble_mean",
-      "ncep_gefs05_ensemble_mean",
-      "ncep_aigefs025_ensemble_mean",
-      "ecmwf_ifs025_ensemble_mean",
-      "ecmwf_aifs025_ensemble_mean",
-      "cmc_gem_geps_ensemble_mean",
-      "bom_access_global_ensemble_mean",
-      "google_weathernext2_ensemble_mean",
-      "ukmo_global_ensemble_mean_20km",
-      "ukmo_uk_ensemble_mean_2km",
-      "meteoswiss_icon_ch1_ensemble_mean",
-      "meteoswiss_icon_ch2_ensemble_mean"
-    ],
-    "type": "string"
-  },
-  {
-    "items": {
-      "enum": [
-        "icon_seamless_eps",
-        "icon_global_eps",
-        "icon_eu_eps",
-        "icon_d2_eps",
-        "dwd_icon_seamless_eps",
-        "dwd_icon_global_eps",
-        "dwd_icon_eu_eps",
-        "dwd_icon_d2_eps",
-        "gfs_seamless",
-        "ncep_gefs_seamless",
-        "ncep_gefs025",
-        "ncep_gefs05",
-        "ncep_aigefs025",
-        "ecmwf_ifs025_ensemble",
-        "ecmwf_aifs025_ensemble",
-        "ecmwf_ifs_europe_ensemble",
-        "ecmwf_aifs_europe_ensemble",
-        "gem_global",
-        "gem_global_ensemble",
-        "cmc_gem_geps",
-        "bom_access_global",
-        "bom_access_global_ensemble",
-        "google_weathernext2_ensemble",
-        "ukmo_global_ensemble_20km",
-        "ukmo_uk_ensemble_2km",
-        "meteoswiss_icon_ch1",
-        "meteoswiss_icon_ch2",
-        "meteoswiss_icon_ch1_ensemble",
-        "meteoswiss_icon_ch2_ensemble",
-        "dwd_icon_eps_ensemble_mean_seamless",
-        "dwd_icon_eps_ensemble_mean",
-        "dwd_icon_eu_eps_ensemble_mean",
-        "dwd_icon_d2_eps_ensemble_mean",
-        "ncep_gefs_ensemble_mean_seamless",
-        "ncep_gefs025_ensemble_mean",
-        "ncep_gefs05_ensemble_mean",
-        "ncep_aigefs025_ensemble_mean",
-        "ecmwf_ifs025_ensemble_mean",
-        "ecmwf_aifs025_ensemble_mean",
-        "cmc_gem_geps_ensemble_mean",
-        "bom_access_global_ensemble_mean",
-        "google_weathernext2_ensemble_mean",
-        "ukmo_global_ensemble_mean_20km",
-        "ukmo_uk_ensemble_mean_2km",
-        "meteoswiss_icon_ch1_ensemble_mean",
-        "meteoswiss_icon_ch2_ensemble_mean"
-      ],
-      "type": "string"
-    },
-    "type": "array"
-  }
-]New value: +[
+  {
+    "enum": [
+      "icon_seamless_eps",
+      "icon_global_eps",
+      "icon_eu_eps",
+      "icon_d2_eps",
+      "dwd_icon_seamless_eps",
+      "dwd_icon_global_eps",
+      "dwd_icon_eu_eps",
+      "dwd_icon_d2_eps",
+      "gfs_seamless",
+      "ncep_gefs_seamless",
+      "ncep_gefs025",
+      "ncep_gefs05",
+      "ncep_aigefs025",
+      "ecmwf_ifs025_ensemble",
+      "ecmwf_aifs025_ensemble",
+      "ecmwf_ifs_europe_ensemble",
+      "ecmwf_aifs_europe_ensemble",
+      "gem_global",
+      "gem_global_ensemble",
+      "cmc_gem_geps",
+      "bom_access_global",
+      "bom_access_global_ensemble",
+      "google_weathernext2_ensemble",
+      "ukmo_global_ensemble_20km",
+      "ukmo_uk_ensemble_2km",
+      "meteoswiss_icon_ch1",
+      "meteoswiss_icon_ch2",
+      "meteoswiss_icon_ch1_ensemble",
+      "meteoswiss_icon_ch2_ensemble",
+      "dwd_icon_eps_ensemble_mean_seamless",
+      "dwd_icon_eps_ensemble_mean",
+      "dwd_icon_eu_eps_ensemble_mean",
+      "dwd_icon_d2_eps_ensemble_mean",
+      "ncep_gefs_ensemble_mean_seamless",
+      "ncep_gefs025_ensemble_mean",
+      "ncep_gefs05_ensemble_mean",
+      "ncep_aigefs025_ensemble_mean",
+      "ecmwf_ifs025_ensemble_mean",
+      "ecmwf_aifs025_ensemble_mean",
+      "cmc_gem_geps_ensemble_mean",
+      "bom_access_global_ensemble_mean",
+      "google_weathernext2_ensemble_mean",
+      "ukmo_global_ensemble_mean_20km",
+      "ukmo_uk_ensemble_mean_2km",
+      "meteoswiss_icon_ch1_ensemble_mean",
+      "meteoswiss_icon_ch2_ensemble_mean"
+    ],
+    "type": "string"
+  },
+  {
+    "items": {
+      "enum": [
+        "icon_seamless_eps",
+        "icon_global_eps",
+        "icon_eu_eps",
+        "icon_d2_eps",
+        "dwd_icon_seamless_eps",
+        "dwd_icon_global_eps",
+        "dwd_icon_eu_eps",
+        "dwd_icon_d2_eps",
+        "gfs_seamless",
+        "ncep_gefs_seamless",
+        "ncep_gefs025",
+        "ncep_gefs05",
+        "ncep_aigefs025",
+        "ecmwf_ifs025_ensemble",
+        "ecmwf_aifs025_ensemble",
+        "ecmwf_ifs_europe_ensemble",
+        "ecmwf_aifs_europe_ensemble",
+        "gem_global",
+        "gem_global_ensemble",
+        "cmc_gem_geps",
+        "bom_access_global",
+        "bom_access_global_ensemble",
+        "google_weathernext2_ensemble",
+        "ukmo_global_ensemble_20km",
+        "ukmo_uk_ensemble_2km",
+        "meteoswiss_icon_ch1",
+        "meteoswiss_icon_ch2",
+        "meteoswiss_icon_ch1_ensemble",
+        "meteoswiss_icon_ch2_ensemble",
+        "dwd_icon_eps_ensemble_mean_seamless",
+        "dwd_icon_eps_ensemble_mean",
+        "dwd_icon_eu_eps_ensemble_mean",
+        "dwd_icon_d2_eps_ensemble_mean",
+        "ncep_gefs_ensemble_mean_seamless",
+        "ncep_gefs025_ensemble_mean",
+        "ncep_gefs05_ensemble_mean",
+        "ncep_aigefs025_ensemble_mean",
+        "ecmwf_ifs025_ensemble_mean",
+        "ecmwf_aifs025_ensemble_mean",
+        "cmc_gem_geps_ensemble_mean",
+        "bom_access_global_ensemble_mean",
+        "google_weathernext2_ensemble_mean",
+        "ukmo_global_ensemble_mean_20km",
+        "ukmo_uk_ensemble_mean_2km",
+        "meteoswiss_icon_ch1_ensemble_mean",
+        "meteoswiss_icon_ch2_ensemble_mean"
+      ],
+      "type": "string"
+    },
+    "minItems": 1,
+    "type": "array"
+  }
+]

addedInput schema / properties / models / description

Added value: +"Required: the ensemble API has no default model. Use e.g. \"icon_seamless_eps\" or \"ncep_gefs_seamless\"."

changedInput schema / required

Previous value: -[
-  "latitude",
-  "longitude"
-]New value: +[
+  "latitude",
+  "longitude",
+  "models"
+]

Changed31 schema fields changedv2.5.0Sep 28, 2026

addedInput schema / $schema

Added value: +"http://json-schema.org/draft-07/schema#"

addedInput schema / additionalProperties
```
Added value: +false
```

addedInput schema / properties / azimuth

Added value: +{
+  "description": "Solar panel azimuth in degrees (0 = south, -90 = east, 90 = west, ±180 = north); used with `tilt`.",
+  "maximum": 180,
+  "minimum": -180,
+  "type": "number"
+}

addedInput schema / properties / cell_selection

Added value: +{
+  "description": "Grid cell to use near a coastline: prefer \"land\", prefer \"sea\", or the \"nearest\" cell.",
+  "enum": [
+    "land",
+    "sea",
+    "nearest"
+  ],
+  "type": "string"
+}

removedInput schema / properties / daily / description

Removed value: -"Daily weather variables to retrieve"

changedInput schema / properties / daily / items / enum

Previous value: -[
-  "temperature_2m_mean",
-  "temperature_2m_min",
-  "temperature_2m_max",
-  "apparent_temperature_mean",
-  "apparent_temperature_min",
-  "apparent_temperature_max",
-  "wind_speed_10m_mean",
-  "wind_speed_10m_min",
-  "wind_speed_10m_max",
-  "wind_direction_10m_dominant",
-  "wind_gusts_10m_mean",
-  "wind_gusts_10m_min",
-  "wind_gusts_10m_max",
-  "precipitation_sum",
-  "precipitation_hours",
-  "rain_sum",
-  "snowfall_sum",
-  "pressure_msl_mean",
-  "pressure_msl_min",
-  "pressure_msl_max",
-  "cloud_cover_mean",
-  "cloud_cover_min",
-  "cloud_cover_max",
-  "relative_humidity_2m_mean",
-  "relative_humidity_2m_min",
-  "relative_humidity_2m_max",
-  "cape_mean",
-  "cape_min",
-  "cape_max",
-  "shortwave_radiation_sum"
-]New value: +[
+  "temperature_2m_mean",
+  "temperature_2m_min",
+  "temperature_2m_max",
+  "apparent_temperature_mean",
+  "apparent_temperature_min",
+  "apparent_temperature_max",
+  "wind_speed_10m_mean",
+  "wind_speed_10m_min",
+  "wind_speed_10m_max",
+  "wind_direction_10m_dominant",
+  "wind_gusts_10m_mean",
+  "wind_gusts_10m_min",
+  "wind_gusts_10m_max",
+  "wind_speed_100m_mean",
+  "wind_speed_100m_min",
+  "wind_speed_100m_max",
+  "wind_direction_100m_dominant",
+  "precipitation_sum",
+  "precipitation_hours",
+  "rain_sum",
+  "snowfall_sum",
+  "pressure_msl_mean",
+  "pressure_msl_min",
+  "pressure_msl_max",
+  "surface_pressure_mean",
+  "surface_pressure_min",
+  "surface_pressure_max",
+  "cloud_cover_mean",
+  "cloud_cover_min",
+  "cloud_cover_max",
+  "relative_humidity_2m_mean",
+  "relative_humidity_2m_min",
+  "relative_humidity_2m_max",
+  "dew_point_2m_mean",
+  "dew_point_2m_min",
+  "dew_point_2m_max",
+  "cape_mean",
+  "cape_min",
+  "cape_max",
+  "shortwave_radiation_sum",
+  "et0_fao_evapotranspiration"
+]

addedInput schema / properties / elevation

Added value: +{
+  "description": "Elevation in metres to adjust the values to; defaults to the terrain height at the point.",
+  "type": "number"
+}

addedInput schema / properties / end_date

Added value: +{
+  "description": "Date in YYYY-MM-DD format.",
+  "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+  "type": "string"
+}

removedInput schema / properties / forecast_days / default
```
Removed value: -7
```

changedInput schema / properties / forecast_days / description

Previous value: -"Number of forecast days"New value: +"Days to forecast, starting today."

changedInput schema / properties / forecast_days / maximum
```
Previous value: -35New value: +36
```
changedInput schema / properties / forecast_days / minimum
```
Previous value: -1New value: +0
```

addedInput schema / properties / forecast_hours

Added value: +{
+  "description": "Hours to forecast; alternative to `forecast_days`.",
+  "maximum": 9007199254740991,
+  "minimum": 0,
+  "type": "integer"
+}

removedInput schema / properties / hourly / description

Removed value: -"Hourly weather variables to retrieve"

addedInput schema / properties / hourly / items / anyOf

Added value: +[
+  {
+    "enum": [
+      "temperature_2m",
+      "relative_humidity_2m",
+      "dew_point_2m",
+      "apparent_temperature",
+      "precipitation",
+      "rain",
+      "snowfall",
+      "snow_depth",
+      "weather_code",
+      "pressure_msl",
+      "surface_pressure",
+      "cloud_cover",
+      "visibility",
+      "wind_speed_10m",
+      "wind_direction_10m",
+      "wind_gusts_10m",
+      "wind_speed_80m",
+      "wind_direction_80m",
+      "wind_speed_100m",
+      "wind_direction_100m",
+      "surface_temperature",
+      "soil_temperature_0_to_10cm",
+      "cape",
+      "et0_fao_evapotranspiration",
+      "vapour_pressure_deficit",
+      "shortwave_radiation",
+      "uv_index",
+      "uv_index_clear_sky",
+      "temperature_2m_min",
+      "temperature_2m_max",
+      "wet_bulb_temperature_2m",
+      "convective_inhibition",
+      "freezing_level_height",
+      "snowfall_height",
+      "sunshine_duration",
+      "snowfall_water_equivalent",
+      "snow_depth_water_equivalent"
+    ],
+    "type": "string"
+  },
+  {
+    "description": "Pressure-level variable <variable>_<level>hPa, e.g. \"temperature_850hPa\".",
+    "pattern": "^(temperature|relative_humidity|wind_speed|wind_direction|geopotential_height|vertical_velocity)_(30|50|70|100|150|200|250|300|400|500|600|700|800|850|900|925|950|975|1000)hPa$",
+    "type": "string"
+  }
+]

removedInput schema / properties / hourly / items / enum

Removed value: -[
-  "temperature_2m",
-  "relative_humidity_2m",
-  "dew_point_2m",
-  "apparent_temperature",
-  "precipitation",
-  "rain",
-  "snowfall",
-  "snow_depth",
-  "weather_code",
-  "pressure_msl",
-  "surface_pressure",
-  "cloud_cover",
-  "visibility",
-  "wind_speed_10m",
-  "wind_direction_10m",
-  "wind_gusts_10m",
-  "wind_speed_80m",
-  "wind_direction_80m",
-  "wind_speed_100m",
-  "wind_direction_100m",
-  "surface_temperature",
-  "soil_temperature_0_to_10cm",
-  "cape",
-  "et0_fao_evapotranspiration",
-  "vapour_pressure_deficit",
-  "shortwave_radiation"
-]

removedInput schema / properties / hourly / items / type
```
Removed value: -"string"
```
removedInput schema / properties / latitude / description
```
Removed value: -"Latitude in WGS84 coordinate system"
```
removedInput schema / properties / longitude / description
```
Removed value: -"Longitude in WGS84 coordinate system"
```

addedInput schema / properties / models / anyOf

Added value: +[
+  {
+    "enum": [
+      "icon_seamless_eps",
+      "icon_global_eps",
+      "icon_eu_eps",
+      "icon_d2_eps",
+      "dwd_icon_seamless_eps",
+      "dwd_icon_global_eps",
+      "dwd_icon_eu_eps",
+      "dwd_icon_d2_eps",
+      "gfs_seamless",
+      "ncep_gefs_seamless",
+      "ncep_gefs025",
+      "ncep_gefs05",
+      "ncep_aigefs025",
+      "ecmwf_ifs025_ensemble",
+      "ecmwf_aifs025_ensemble",
+      "ecmwf_ifs_europe_ensemble",
+      "ecmwf_aifs_europe_ensemble",
+      "gem_global",
+      "gem_global_ensemble",
+      "cmc_gem_geps",
+      "bom_access_global",
+      "bom_access_global_ensemble",
+      "google_weathernext2_ensemble",
+      "ukmo_global_ensemble_20km",
+      "ukmo_uk_ensemble_2km",
+      "meteoswiss_icon_ch1",
+      "meteoswiss_icon_ch2",
+      "meteoswiss_icon_ch1_ensemble",
+      "meteoswiss_icon_ch2_ensemble",
+      "dwd_icon_eps_ensemble_mean_seamless",
+      "dwd_icon_eps_ensemble_mean",
+      "dwd_icon_eu_eps_ensemble_mean",
+      "dwd_icon_d2_eps_ensemble_mean",
+      "ncep_gefs_ensemble_mean_seamless",
+      "ncep_gefs025_ensemble_mean",
+      "ncep_gefs05_ensemble_mean",
+      "ncep_aigefs025_ensemble_mean",
+      "ecmwf_ifs025_ensemble_mean",
+      "ecmwf_aifs025_ensemble_mean",
+      "cmc_gem_geps_ensemble_mean",
+      "bom_access_global_ensemble_mean",
+      "google_weathernext2_ensemble_mean",
+      "ukmo_global_ensemble_mean_20km",
+      "ukmo_uk_ensemble_mean_2km",
+      "meteoswiss_icon_ch1_ensemble_mean",
+      "meteoswiss_icon_ch2_ensemble_mean"
+    ],
+    "type": "string"
+  },
+  {
+    "items": {
+      "enum": [
+        "icon_seamless_eps",
+        "icon_global_eps",
+        "icon_eu_eps",
+        "icon_d2_eps",
+        "dwd_icon_seamless_eps",
+        "dwd_icon_global_eps",
+        "dwd_icon_eu_eps",
+        "dwd_icon_d2_eps",
+        "gfs_seamless",
+        "ncep_gefs_seamless",
+        "ncep_gefs025",
+        "ncep_gefs05",
+        "ncep_aigefs025",
+        "ecmwf_ifs025_ensemble",
+        "ecmwf_aifs025_ensemble",
+        "ecmwf_ifs_europe_ensemble",
+        "ecmwf_aifs_europe_ensemble",
+        "gem_global",
+        "gem_global_ensemble",
+        "cmc_gem_geps",
+        "bom_access_global",
+        "bom_access_global_ensemble",
+        "google_weathernext2_ensemble",
+        "ukmo_global_ensemble_20km",
+        "ukmo_uk_ensemble_2km",
+        "meteoswiss_icon_ch1",
+        "meteoswiss_icon_ch2",
+        "meteoswiss_icon_ch1_ensemble",
+        "meteoswiss_icon_ch2_ensemble",
+        "dwd_icon_eps_ensemble_mean_seamless",
+        "dwd_icon_eps_ensemble_mean",
+        "dwd_icon_eu_eps_ensemble_mean",
+        "dwd_icon_d2_eps_ensemble_mean",
+        "ncep_gefs_ensemble_mean_seamless",
+        "ncep_gefs025_ensemble_mean",
+        "ncep_gefs05_ensemble_mean",
+        "ncep_aigefs025_ensemble_mean",
+        "ecmwf_ifs025_ensemble_mean",
+        "ecmwf_aifs025_ensemble_mean",
+        "cmc_gem_geps_ensemble_mean",
+        "bom_access_global_ensemble_mean",
+        "google_weathernext2_ensemble_mean",
+        "ukmo_global_ensemble_mean_20km",
+        "ukmo_uk_ensemble_mean_2km",
+        "meteoswiss_icon_ch1_ensemble_mean",
+        "meteoswiss_icon_ch2_ensemble_mean"
+      ],
+      "type": "string"
+    },
+    "type": "array"
+  }
+]

removedInput schema / properties / models / description
```
Removed value: -"Ensemble models to use"
```

removedInput schema / properties / models / items

Removed value: -{
-  "enum": [
-    "meteofrance_arome_france_hd",
-    "meteofrance_arome_france",
-    "meteofrance_arpege_europe",
-    "icon_eu",
-    "icon_global",
-    "ecmwf_ifs025",
-    "gfs013"
-  ],
-  "type": "string"
-}

removedInput schema / properties / models / type
```
Removed value: -"array"
```

addedInput schema / properties / past_days

Added value: +{
+  "description": "Days before today to include, in addition to the forecast.",
+  "maximum": 92,
+  "minimum": 0,
+  "type": "integer"
+}

addedInput schema / properties / past_hours

Added value: +{
+  "description": "Hours before now to include; alternative to `past_days`.",
+  "maximum": 9007199254740991,
+  "minimum": 0,
+  "type": "integer"
+}

addedInput schema / properties / start_date

Added value: +{
+  "description": "Date in YYYY-MM-DD format.",
+  "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+  "type": "string"
+}

addedInput schema / properties / temporal_resolution

Added value: +{
+  "description": "\"native\" keeps each model's own time step; \"hourly\", \"hourly_3\" and \"hourly_6\" resample to 1, 3 or 6 hours.",
+  "enum": [
+    "native",
+    "hourly",
+    "hourly_3",
+    "hourly_6"
+  ],
+  "type": "string"
+}

addedInput schema / properties / tilt

Added value: +{
+  "description": "Solar panel tilt in degrees (0 = flat, 90 = vertical); with `azimuth`, sets global_tilted_irradiance.",
+  "maximum": 90,
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / timeformat

Added value: +{
+  "default": "iso8601",
+  "enum": [
+    "iso8601",
+    "unixtime"
+  ],
+  "type": "string"
+}

changedInput schema / properties / timezone / description

Previous value: -"Timezone for timestamps"New value: +"IANA time zone (e.g. \"Europe/Paris\"), or \"auto\" for the location's own. Default GMT."

changedInput schema / required

Previous value: -[
-  "latitude",
-  "longitude",
-  "models"
-]New value: +[
+  "latitude",
+  "longitude"
+]

First observedv1.1.3Jan 31, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds one genuine behavioral fact — the no-default-model requirement — but says nothing about how uncertainty is represented in the response (members, percentiles, mean) or any rate/quota limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with purpose before the required-parameter caveat. No padding, though the inline model examples are somewhat redundant with the schema enum.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 21-parameter tool with no output schema and only 62% parameter description coverage, the description covers just the headline requirement. It does not explain that ensemble output differs in shape from deterministic forecasts, which is the main thing an agent needs to anticipate when invoking it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 62%, and the description's only parameter content is the `models` requirement, which is also stated in the schema's own models description. It adds example model IDs, but largely duplicates structured data and leaves other 20-parameter semantics to the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource ('Get ensemble forecasts') with a distinguishing scope clause: 'showing forecast uncertainty with multiple model runs.' This clearly separates it from the deterministic siblings like ecmwf_forecast, gfs_forecast and dwd_icon_forecast.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description notes that `models` is required because the API has no default, which is a useful usage constraint, but it never says when to prefer this tool over the 16 sibling forecast tools or when ensemble output is warranted versus a deterministic run.

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

Deploy Server

Ensemble Forecast

Instructions

Input Schema

Schema Changelog

TDQS

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