eCFR

Compare the text of a CFR section at two different dates. Useful for understanding what changed in a regulatory amendment. Returns 'changes' (each paragraph that was added, removed or changed, with its before and after text; also heading, table and pending-amendment-link changes), 'identical' when nothing differs, and the parsed text at both dates side by side. When both texts together are too long to send, the full texts are left out (texts_omitted) and 'changes' is kept. changes_only=True leaves the full texts out every time: the short answer to "what changed". Dates must be in YYYY-MM-DD format. Historical snapshot availability varies by title and section, including some dates before 2017. Use get_version_history to discover dates. Both dates must not exceed the title's up_to_date_as_of value. This tool always returns the section-level XML parsed -- pass a small section_id like '15.305', not a whole part. Whole-part comparisons can exceed 100 KB per side.

Find a term's definition in FAR 2.101, the FAR's main definitions section. Returns each matching definition whole (the defining paragraph and every sub-paragraph under it), first, marked kind='definition'. Matching ignores case, hyphens, spacing, plurals, a trailing "means", and the acronym 2.101 puts in a name, so 'service-disabled veteran-owned small business concern', 'SDVOSB concern', 'COTS', 'commercial services' and 'contract means' all find their definitions. Other 2.101 paragraphs that use the term (whole words only) follow as kind='mention', each naming the definition it sits in. When 2.101 doesn't define the term, the tool searches the rest of the FAR (chapter 1), then the DFARS (chapter 2), for "<term>" means and returns where it is defined, with the definition text, under defined_elsewhere (for example 19.001 and 52.219-14 for 'similarly situated entity'; 204.7301 for 'covered defense information'), plus did_you_mean suggestions from 2.101. term must be at least 3 characters. max_matches caps the number of matches returned (default 20, max 100); definitions are never cut, and truncated says whether mentions were left out.

Find CFR sections changed since a given date, removals included. Built on eCFR's version history: every version issued on or after since_date, newest first. Each change says whether the section was amended, removed (change='removed'), or re-issued with no text change (substantive=false). 'summary' counts each kind. A section changed twice appears twice. since_date must be in YYYY-MM-DD format. Filter with title (default 48), chapter (Title 48: 1 = FAR, 2 = DFARS, 99 = CAS) or part. per_page (default 100, max 5000) and page step through long lists; total_pages says how many pages there are. Common pattern: find FAR changes since a specific date to check for regulatory updates that might affect ongoing acquisitions.

Get the breadcrumb hierarchy path for a section, part, or appendix. Returns ancestors from title down to the target node: title > chapter > subchapter > part > subpart > section. Useful for understanding where a section sits in the CFR hierarchy and what regulation it belongs to. part/subpart/section/appendix accept int or string. The answer says which date it describes.

Get the full text of a CFR section, subpart, part, or appendix. Returns parsed clean text by default: heading, paragraphs and citations, plus tables, notes, examples, images, pending_amendments and editorial_notes when present. Tables, notes and examples are numbered, and a marker like "[See table 1: ...]" sits in the paragraphs where each appears. [fn N] marks a footnote reference. pending_amendments means eCFR links a published amendment that may not be in effect yet. A subpart, part or appendix request returns one object per section under 'sections', each with its own section number and heading. Set raw_xml=True to get the original XML instead. Answers longer than about 60,000 characters come in pages: the reply says page and total_pages, and page=2 (and so on) returns the rest. Specify the narrowest scope possible to keep responses manageable: - section='15.305' for a single FAR section - subpart='15.3' for a subpart - part='15' for an entire part (can be large) - chapter='1' for an entire chapter (often >1 MB, avoid) - appendix='Appendix A to Chapter 2' (with chapter='2') for a DFARS appendix Date auto-resolves to the latest available if not provided. Do NOT use today's date directly -- eCFR lags 1-2 business days and today often 404s. Title 48 = FAR/DFARS. Chapter 1 = FAR (Parts 1-99), Chapter 2 = DFARS (Parts 200-299). Other chapters = agency FAR supplements (GSAR, VAAR, HSAR, etc.). For DFARS clauses, use chapter='2' (e.g., section='252.227-7014'). part/subpart/section accept int or string. Common prefix mistakes like section='FAR 15.305' or '48 CFR 15.305' are stripped automatically, and trailing paragraph cites like section='15.305(a)(2)' resolve to the base section '15.305'.

Get the hierarchical table of contents for a CFR title or subset. Returns a nested tree of titles, chapters, parts, subparts, and sections with identifiers, descriptions, and byte sizes, plus the date it describes. IMPORTANT: Does NOT support section-level filtering (returns 400). Use part or subpart, then walk the children to find sections. Common patterns: - part='15' for FAR Part 15 structure - subpart='15.3' for just that subpart's sections - chapter='1', depth=2 for the FAR's subchapters and parts only - appendix='Appendix A to Part 200' with part='200' (title 2) for one appendix depth keeps that many levels below the node asked for (part='19', depth=1 gives Part 19's subparts); deeper levels are replaced by 'children_omitted' (how many there were). For the sections of one part, list_sections_in_part is shorter. A tree too large to send at once (a whole chapter is about 1 MB) is cut to the deepest depth that fits, and 'note' says so. subchapter needs chapter in Title 48 (each chapter has its own subchapter A, B, ...). part/subpart/chapter/appendix accept int or string.

Get editorial corrections for a CFR title, newest first. Returns corrections with CFR references, corrective actions, error dates, and FR citations, sorted by the date the error was corrected, newest first. Useful for checking whether a section's current text has been corrected since its last amendment. section (e.g. '52.204-21'), part (e.g. '52') or chapter (e.g. '2' for the DFARS) keeps only corrections that touch it. since_year keeps corrections with year >= since_year. limit caps how many are returned (default 50, max 1000); truncated says whether older ones were left out. Title 48 has ~280 corrections since 2005.

Get the most recent available date for a CFR title. CRITICAL: eCFR lags 1-2 business days behind the Federal Register. Using today's date on versioner endpoints causes 404 errors. Call this first to get the safe date, then pass it to other tools. Default title 48 = Federal Acquisition Regulations System (FAR, DFARS, and all agency supplements). Other common titles: 2 (Grants/Agreements), 5 (Administrative Personnel), 29 (Labor), 41 (Public Contracts). Raises ValueError for titles 1-50 that are reserved (no content).

Get the version history of a CFR section, subpart, or part. Returns content_versions (each with date, amendment_date, issue_date, identifier, name, substantive and removed), every version eCFR lists: all of eCFR's pages are read, so Part 52's 2,264 versions are all there. Versions are grouped by section, oldest first. since_date/until_date (YYYY-MM-DD) keep versions dated in that range. per_page (default 200, max 1000) and page step through long histories; total_count and total_pages say how many there are. 'substantive' is eCFR's flag: true when the version's text differs from the one before, including editorial edits such as citation fixes and the "Link to an amendment published at ..." notice eCFR adds when a rule is published; false when re-issued with no text change. To see what actually changed, use compare_versions on the dates. 'removed' true means the section was removed on that date. Version metadata and text snapshots may include dates before 2017. Availability varies by title and section. Use the returned history dates for reads or comparisons; a missing old snapshot produces an availability error. A 2017-01-01 baseline often means unchanged since before 2017. part/subpart/section accept int or string.

List all agencies with their CFR title and chapter references. Returns agency names, slugs, and which CFR titles/chapters they own. Useful for finding which chapter corresponds to an agency's FAR supplement. summary_only (default True) strips the `children` and most of `cfr_references` to keep the response compact (~20 KB vs ~100 KB). References owned by child agencies are merged into the parent row, so chapter lookups like DFARS (chapter 2, on a DoD child agency) still work in summary mode. Set False for the full raw payload including children.

List all sections and appendices in a CFR part with their headings. Returns 'sections' in order, each {identifier, heading}, with type='appendix' on appendices (2 CFR 200's Appendix I-XII, for example) and reserved=true on reserved sections, plus 'subparts' (each with its heading, section_count and first and last section). Useful for seeing the scope of a part before reading specific sections. The part number alone is enough: chapter is optional (Title 48 parts are unique: 52 = FAR, 252 = DFARS, 552 = GSAR) and the answer reports the chapter the part is in. subpart (e.g. '52.2') lists one subpart. A list too long to send at once (FAR Part 52 has 680 entries) comes in pages: page and total_pages say where you are; page=2 gets the rest. detail=True adds eCFR's label, size and received_on for each entry (received_on is when eCFR processed the text, not when it was amended; get_version_history has amendment dates). part_number accepts int or string.

Convenience tool: look up the current text of a FAR, DFARS or FAR supplement section or clause. Pass a section identifier like '15.305', '52.212-4', '2.101', 'DFARS 252.204-7012' or '552.238-81'. The chapter comes from the number (52.x = FAR, 252.x = DFARS, 552.x = GSAR, 852.x = VAAR, 1852.x = NFS, 3052.x = HSAR), so chapter is optional. Prefixes like 'FAR', 'DFARS', '§' and '48 CFR', en dashes, and trailing paragraph cites such as '(d)(11)(xviii)' are handled. Auto-resolves the latest available date. Returns parsed clean text with heading, paragraphs and citations, plus tables, notes (such as drafting notes, which are not clause text), examples, images and pending_amendments when present; see get_cfr_content. A clause longer than about 60,000 characters comes in pages: use page=2 and so on. Common FAR sections: 2.101 (Definitions), 9.104-1 (Responsibility), 15.305 (Proposal Evaluation), 19.502-2 (Small Business Set-Asides), 52.212-4 (Commercial Terms), 52.212-5 (Required Commercial Terms).

Full-text search across the Code of Federal Regulations. Returns matching sections with excerpts, headings, scores, and hierarchy. current_only=True (default) returns only text in effect now. eCFR's own "current" index still lists some superseded and removed versions, so each hit is checked against the section's version history: older copies of a section are dropped, and hits whose text has since been replaced or removed are dropped and listed under current_check ('superseded' with the current version's date, 'removed' with the removal date). Up to 10 parts per page are checked; any hit not checked is marked. current_only=False returns every historical version, so a section amended 5 times appears 5 times. Search caps at 10,000 total results. Use hierarchy filters (title, chapter, part) to narrow if you hit the cap. chapter/part/subpart/section filters need a title; without one, title 48 is assumed (title_assumed says so). Labels like 'FAR Part 15', 'Subpart 15.3' or '§ 52.212-5' are read as 15, 15.3 and 52.212-5. Most titles other than 48 number chapters in Roman numerals (2 CFR chapter 'II'). order controls result ordering: 'relevance' (default), 'newest_first', 'oldest_first', 'hierarchy', or 'citations'. agency_slugs filters to one or more agencies (single slug string or a list, e.g. 'defense-acquisition-regulations-system'). Use list_agencies() to find slugs. last_modified_after/before use YYYY-MM-DD format and filter by the date sections were last amended. Useful for finding recent regulatory changes. per_page accepts 1 to 5000 (default 20); paginate with page for more.