Added value: +"Station ID. Trims surrounding whitespace, uppercases IDs, and accepts bare 11-character GHCN aliases (USW00024233 → GHCND:USW00024233). Other namespaced IDs remain accepted."

Added value: +"^\\s*(?:[A-Za-z]{2}[A-Za-z0-9]{9}|[^:\\s]+:[^\\s]+)\\s*$"

Previous value: -"Unit system for returned values. Without this parameter, GHCND returns raw tenths-of-unit integers (TMAX=256 = 25.6°C). Strongly recommended: pass metric (SI units) or standard (Fahrenheit/inches). Optional."New value: +"Request metric or standard conversion. Omission preserves datatype-specific raw values: GHCND TMAX/TMIN tenths °C, PRCP tenths mm, SNOW/SNWD whole mm; GSOM/GSOY temperature/precipitation °C/mm; NORMAL_* temperature normals tenths °F and precipitation normals hundredths inches; HPCP/QPCP hundredths inches. Examples are not complete unit metadata. Optional."

Previous value: -"Machine-readable failure mode. Declared by this tool: `service_unavailable`: NOAA CDO API is unreachable or returning errors. `rate_limited`: NOAA CDO throttled the request — the configured token went over its rate limit. `date_range_exceeded`: endDate is past the end of the calendar month 1 year after startDate for sub-daily/daily/radar datasets (GHCND, PRECIP_*, NORMAL_DLY, NORMAL_HLY, NEXRAD2, NEXRAD3), or 10 years after it for monthly/annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN). `upstream_auth_failed`: NOAA CDO rejected the API token this server is configured with. `validation_error`: Bad dataset ID, date format, or unknown station/location/datatype ID. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `service_unavailable`: NOAA CDO API is unreachable or returning errors. `rate_limited`: NOAA CDO throttled the request — the configured token went over its rate limit. `date_range_exceeded`: endDate is past the end of the calendar month 1 year after startDate for sub-daily/daily/radar datasets (GHCND, PRECIP_*, NORMAL_DLY, NORMAL_HLY, NEXRAD2, NEXRAD3), or 10 years after it for monthly/annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN). `upstream_auth_failed`: NOAA CDO rejected the API token this server is configured with. `validation_error`: Bad dataset ID, date format, unknown station/location/datatype ID, or encoded observation query exceeding 4000 characters. Other values are possible when a failure originates below the handler."

Previous value: -"Page-limit adjustment and empty or exhausted-page guidance. Omitted when no guidance applies."New value: +"Composed guidance for station ID normalization, page-limit adjustments, raw units, missing precipitation, GHCND quality-check failures, and empty or exhausted pages. Omitted when no guidance applies."

Previous value: -"Quality flags and measurement attributes. Omitted when not provided."New value: +"Untouched upstream attributes. GHCND positions are measurement, quality, source, observation time; other datasets have their own layouts documented at https://www.ncei.noaa.gov/pub/data/cdo/documentation/."

Added value: +{
+  "additionalProperties": false,
+  "description": "Decoded GHCND attributes only. Absent trailing positions remain omitted; raw attributes and numeric values are retained.",
+  "properties": {
+    "measurement": {
+      "description": "GHCND measurement flag; an explicit blank is preserved.",
+      "type": "string"
+    },
+    "observationTime": {
+      "description": "GHCND local observation time, preserving leading zeros and explicit blanks.",
+      "type": "string"
+    },
+    "quality": {
+      "description": "GHCND quality flag; a nonblank code means a failed quality check. Explicit blanks are preserved.",
+      "type": "string"
+    },
+    "source": {
+      "description": "GHCND source flag, including unknown codes and explicit blanks.",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Added value: +{
+  "const": true,
+  "description": "True for a documented PRECIP_HLY/HPCP or PRECIP_15/QPCP missing sentinel; value is omitted.",
+  "type": "boolean"
+}

Previous value: -"Observed value. Unit depends on the dataset and units parameter. For GHCND without units, this is a raw tenths-of-unit integer."New value: +"Observed value, omitted for identified missing precipitation. With units omitted, scale depends on datatype: GHCND TMAX/TMIN tenths °C, PRCP tenths mm, SNOW/SNWD whole mm; GSOM/GSOY temperature/precipitation °C/mm; NORMAL_* temperature normals tenths °F, precipitation normals hundredths inches; HPCP/QPCP hundredths inches. Examples are not universal conversion rules."

Previous value: -[
-  "date",
-  "datatype",
-  "station",
-  "value"
-]New value: +[
+  "date",
+  "datatype",
+  "station"
+]

Previous value: -"Maximum number of records to return (1–1000). Defaults to 25."New value: +"Maximum number of records to return (1–1000). Defaults to 25. Larger positive integers are clamped to 1000 with a notice unless NOAA_CLAMP_LIMITS=false."

Previous value: -1000New value: +9007199254740991

Previous value: -"Guidance when no records were returned — echoes query parameters and suggests how to broaden."New value: +"Page-limit adjustment and empty or exhausted-page guidance. Omitted when no guidance applies."

Previous value: -"1-based starting index of this page as returned by the NOAA CDO API."New value: +"Zero-based starting index of this page, echoing the requested offset."

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +false

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "results",
+      "totalCount",
+      "effectiveQuery"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `service_unavailable`: NOAA CDO API is unreachable or returning errors. `rate_limited`: NOAA CDO throttled the request — the configured token went over its rate limit. `date_range_exceeded`: endDate is past the end of the calendar month 1 year after startDate for sub-daily/daily/radar datasets (GHCND, PRECIP_*, NORMAL_DLY, NORMAL_HLY, NEXRAD2, NEXRAD3), or 10 years after it for monthly/annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN). `upstream_auth_failed`: NOAA CDO rejected the API token this server is configured with. `validation_error`: Bad dataset ID, date format, or unknown station/location/datatype ID. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "service_unavailable",
+            "rate_limited",
+            "date_range_exceeded",
+            "upstream_auth_failed",
+            "validation_error"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

Removed value: -[
-  "results",
-  "totalCount",
-  "effectiveQuery"
-]

Previous value: -"Dataset ID to query (e.g., GHCND for daily data, GSOM for monthly, GSOY for annual, NORMAL_DLY/MLY/ANN/HLY for 1981–2010 climate normals). Determines date range limit: GHCND/PRECIP_*/NORMAL_DLY/NORMAL_HLY allow 1-year max per request; GSOM/GSOY/NORMAL_MLY/NORMAL_ANN allow 10-year max."New value: +"Dataset ID to query (e.g., GHCND for daily data, GSOM for monthly, GSOY for annual, NORMAL_DLY/MLY/ANN/HLY for 1981–2010 climate normals, NEXRAD2/NEXRAD3 for weather radar). Determines date range limit: GHCND/PRECIP_*/NORMAL_DLY/NORMAL_HLY/NEXRAD2/NEXRAD3 allow 1-year max per request; GSOM/GSOY/NORMAL_MLY/NORMAL_ANN allow 10-year max."

Previous value: -"End date for observations (YYYY-MM-DD). Must be within 1 year of startDate for sub-daily/daily datasets (GHCND, PRECIP_15, PRECIP_HLY, NORMAL_DLY, NORMAL_HLY) or within 10 years for monthly/annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN). For any NORMAL_* dataset use 2010-12-31."New value: +"End date for observations (YYYY-MM-DD). Must be within 1 year of startDate for sub-daily/daily/radar datasets (GHCND, PRECIP_15, PRECIP_HLY, NORMAL_DLY, NORMAL_HLY, NEXRAD2, NEXRAD3) or within 10 years for monthly/annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN) — measured to the end of the calendar month that many years after startDate, so a full calendar year (2024-01-01 to 2024-12-31) always fits. For any NORMAL_* dataset use 2010-12-31."

Previous value: -"One or more station IDs to filter by (e.g., [\"GHCND:USC00450974\"]). Obtain from noaa_climate_find_stations. Multiple IDs return comparative readings across stations. Optional."New value: +"One or more station IDs to filter by (e.g., [\"GHCND:USW00024233\"]). Obtain from noaa_climate_find_stations. Multiple IDs return comparative readings across stations. Optional."

Added value: +1

Added value: +1

Added value: +"^(?:\\d{4}(?:0[1-9]|1[0-2])(?:0[1-9]|[12]\\d|3[01])|\\d{4}-(?:0?[1-9]|1[0-2])-(?:0?[1-9]|[12]\\d|3[01])(?:T(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?)?)$"

Added value: +1

Added value: +1

Added value: +"^(?:\\d{4}(?:0[1-9]|1[0-2])(?:0[1-9]|[12]\\d|3[01])|\\d{4}-(?:0?[1-9]|1[0-2])-(?:0?[1-9]|[12]\\d|3[01])(?:T(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?)?)$"

Added value: +1

Added value: +1

Added value: +{
+  "description": "True when the requested offset is past the end of a non-empty result set — the page is empty but matches exist. Omitted otherwise.",
+  "type": "boolean"
+}