Previous value: -"The \"today\" the open-window filter used (ISO 8601)."New value: +"The \"today\" the open window was computed from — the current date in US Eastern time (ISO 8601). A comment period stays open through 11:59 PM Eastern on its close date."

Previous value: -"Whether comment counts were enriched (REGULATIONS_GOV_API_KEY present)."New value: +"Whether REGULATIONS_GOV_API_KEY is set, which decides whether regulations_get_docket and regulations_find_comments can follow up on a row. Every row field is filled either way."

Previous value: -"Guidance when nothing matched, when the page is past the end, when the window was truncated, or that comment counts are unavailable without a key."New value: +"Guidance when nothing matched, when the page is past the end, or when the window was truncated."

Previous value: -"Comment count from the FR document's Regulations.gov info; null when unkeyed or not on Regulations.gov."New value: +"Comments Regulations.gov received on this document, as the Federal Register reports it; null when not on Regulations.gov. Can exceed the comment records regulations_find_comments lists."

Added value: +{
+  "description": "Regulations.gov page for submitting a comment on this document, as the Federal Register lists it; null when it lists none.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -"Comment-period close date (ISO 8601)."New value: +"Last day of the comment period (ISO 8601), inclusive, in Eastern time."

Previous value: -"Whole days from asOf until the comment period closes."New value: +"Whole days from asOf to commentsCloseOn; 0 means comments close at the end of today."

Previous value: -"Docket IDs — chain into regulations_get_docket / find_comments."New value: +"Docket numbers as the Federal Register prints them — an agency's own number (\"REG-101355-26\"), or an ID inside a wrapper (\"Docket No. FAA-2026-8449\"). Pass one to regulations_search_rules as docket_id. Not always a Regulations.gov ID: for regulations_get_docket / regulations_find_comments use regulationsGovDocketId."

Added value: +{
+  "description": "Regulations.gov docket ID — chains into regulations_get_docket / regulations_find_comments(docket_id). Null when the document is not on Regulations.gov. An <AGENCY>_FRDOC_0001 docket (EPA_FRDOC_0001 holds 3,451 documents) is Regulations.gov's catch-all for Federal Register documents outside a rulemaking docket, so this document's comments come from regulationsGovDocumentId instead.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Added value: +{
+  "description": "Regulations.gov document ID — pass as document_object_id to regulations_find_comments for the comments filed on this document. Null when absent.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -[
-  "documentNumber",
-  "title",
-  "type",
-  "agencies",
-  "publicationDate",
-  "commentsCloseOn",
-  "daysRemaining",
-  "docketIds",
-  "commentCount"
-]New value: +[
+  "documentNumber",
+  "title",
+  "type",
+  "agencies",
+  "publicationDate",
+  "commentsCloseOn",
+  "daysRemaining",
+  "docketIds",
+  "regulationsGovDocketId",
+  "regulationsGovDocumentId",
+  "commentCount",
+  "commentUrl"
+]

Previous value: -"Filter to one or more agencies by Federal Register agency slug (e.g. \"environmental-protection-agency\")."New value: +"Filter to one or more agencies by Federal Register agency slug (e.g. \"environmental-protection-agency\") — lowercase kebab-case, not a name or acronym. Every row lists its agencies with their slugs; read agencies[].slug off a row here or in regulations_search_rules. One unrecognized slug fails the whole request."

Previous value: -"Only rules whose comment period closes on or before this date, ISO 8601 (YYYY-MM-DD). Use to find deadlines you need to act on soon."New value: +"Only documents whose comment period closes on or before this date, ISO 8601 (YYYY-MM-DD), a real calendar day. Use to find deadlines you need to act on soon."

Previous value: -"Page number (1–50). The FR caps total_pages at 50; with per_page=100 this covers up to 5,000 open rules."New value: +"Page number, default 1. Pages run over the whole open window in closing-date order; totalPages and nextPage in the response say how far it goes."

Previous value: -50New value: +10000

Previous value: -"Results per page (2–100, default 20). The Federal Register API treats exactly 1 as its default page size instead of returning one result."New value: +"Documents per page (1–100, default 20)."

Previous value: -2New value: +1

Previous value: -"Full-text filter across open rules. Omit to list all rules currently open for comment."New value: +"Full-text filter across open documents. Omit to list every document currently open for comment."

Added value: +{
+  "description": "Document types to include: PRORULE (proposed rules), RULE (final rules that request comment, including direct final and interim final rules), NOTICE (information-collection and other notices with comment periods — a much larger set). Default, and when empty: [\"PRORULE\", \"RULE\"].",
+  "items": {
+    "enum": [
+      "PRORULE",
+      "RULE",
+      "NOTICE"
+    ],
+    "type": "string"
+  },
+  "type": "array"
+}

Previous value: -[
-  {
-    "not": {
-      "required": [
-        "error"
-      ]
-    },
-    "required": [
-      "asOf",
-      "keyed",
-      "results",
-      "totalCount"
-    ]
-  },
-  {
-    "required": [
-      "error"
-    ]
-  }
-]New value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "asOf",
+      "keyed",
+      "results",
+      "totalCount",
+      "totalPages"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

Added value: +{
+  "description": "The Federal Register document limit that was reached.",
+  "type": "number"
+}

Previous value: -"Machine-readable failure mode. Declared by this tool: `upstream_unavailable`: Federal Register returned a 5xx, timed out, or served an HTML error page. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `upstream_unavailable`: Federal Register returned a 5xx, timed out, or served an HTML error page. `invalid_filter`: The Federal Register rejected a filter value — most often an agency name or acronym passed where a slug belongs. Other values are possible when a failure originates below the handler."

Previous value: -[
-  "upstream_unavailable"
-]New value: +[
+  "upstream_unavailable",
+  "invalid_filter"
+]

Added value: +{
+  "description": "Page to request next — present only when documents remain past this page.",
+  "type": "number"
+}

Previous value: -"Guidance when nothing matched, or that comment counts are unavailable without a key."New value: +"Guidance when nothing matched, when the page is past the end, when the window was truncated, or that comment counts are unavailable without a key."

Previous value: -"Rules open for comment (this page), closing soonest first."New value: +"Documents open for comment on this page, closing soonest first; documents closing the same day are ordered by document number."

Previous value: -"One open-for-comment rule."New value: +"One document open for comment."

Previous value: -"Issuing agency names."New value: +"Issuing agencies."

Added value: +false

Added value: +"One issuing agency."

Added value: +{
+  "name": {
+    "description": "Agency name.",
+    "type": "string"
+  },
+  "slug": {
+    "description": "Federal Register agency slug — pass it back as the agencies filter. Null when the Federal Register lists the agency by raw name only, so it cannot be filtered on.",
+    "type": [
+      "string",
+      "null"
+    ]
+  }
+}

Added value: +[
+  "name",
+  "slug"
+]

Previous value: -"string"New value: +"object"

Previous value: -"Rule title."New value: +"Document title."

Previous value: -"Document type."New value: +"Document type — \"Proposed Rule\", \"Rule\", or \"Notice\"; \"Unknown\" when unlisted."

Previous value: -"Results returned on this page."New value: +"Documents returned on this page."

Previous value: -"Total rules open for comment matching the filters."New value: +"Documents open for comment matching the filters — the window the pages run over."

Added value: +{
+  "description": "Pages in the window at this per_page.",
+  "type": "number"
+}

Previous value: -"True when matches exceed the FR 5,000-record navigation ceiling."New value: +"True when the Federal Register reported its 10,000-document maximum, so the window holds only the 10,000 most recently published matches."

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

Added value: +[
+  "number",
+  "null"
+]

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

Added value: +false

Previous value: -"Results per page (1–100, default 20)."New value: +"Results per page (2–100, default 20). The Federal Register API treats exactly 1 as its default page size instead of returning one result."

Previous value: -1New value: +2

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": [
+      "asOf",
+      "keyed",
+      "results",
+      "totalCount"
+    ]
+  },
+  {
+    "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: `upstream_unavailable`: Federal Register returned a 5xx, timed out, or served an HTML error page. Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "upstream_unavailable"
+          ],
+          "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: -[
-  "asOf",
-  "keyed",
-  "results",
-  "totalCount"
-]