From 4de915b557f684040b940e9668662164b461a497 Mon Sep 17 00:00:00 2001
From: Jared Knowles <jared@civilytics.com>
Date: Sat, 18 Jul 2026 23:33:02 -0400
Subject: [PATCH] feat: cog_recipes + recipe= + signposting suggestions

Adds cog_recipes() to list the curated harmonization_recipes catalog (24
recipes / schema_version >= 5), and a recipe= argument on cog_spending()/
cog_revenue() that runs a recipe's generic multi-code join instead of the
category view: SUM(amt * weight) across whichever component codes are
present for a (year, canonical_govid), scoped by gov_type_scope. The join
deliberately does not filter is_aggregate -- the wide era (<= 2011) exposes
these split families (corrections 04+05, IG *89/*47, U4- rents, etc.) ONLY
as aggregate rows, with leaf codes first appearing in 2012, so excluding
aggregates would zero out the wide-era half of every recipe. This is safe
by corpus construction: wide-era rows are aggregate-only, modern rows are
leaf-only, and every component is year-scoped, so there is no
double-counting. recipe= is mutually exclusive with category=; the result's
subtype column reads "recipe" and category reads the recipe's label.

Adds recipe-component-driven signposting: when a basis="harmonized" +
category query comes back with zero rows in a requested year, and a
harmonization recipe covering that category would actually produce rows
for this government in that year (via the same join .run_recipe() uses),
the recipe is surfaced in provenance$suggestions plus one
cli::cli_inform() message. This is deliberately keyed off recipe
components rather than harmonization_map's suggested_recipe_id column
(which is empty on every live row -- the wide era's split families are
NA-by-construction via aggregate exclusion, not an NA ruling to hang a
suggestion off of).

Also populates the previously-always-empty provenance$series_break_refs
(schema v5 only: series_breaks_pq rows whose fin_code is among the
observed codes and whose break_year falls in the requested span), and
extends cog_explain() with Basis/Harmonization/Recipe/Suggestions/Series
breaks sections.
---
 NAMESPACE                      |   1 +
 R/explain.R                    |  64 +++++++++++
 R/provenance.R                 |  15 ++-
 R/recipes.R                    | 167 +++++++++++++++++++++++++++++
 R/revenue.R                    |   5 +-
 R/series_breaks.R              |  22 ++++
 R/spending.R                   |  67 ++++++++++--
 R/suggestions.R                | 119 +++++++++++++++++++++
 man/cog_recipes.Rd             |  22 ++++
 man/cog_revenue.Rd             |  10 +-
 man/cog_spending.Rd            |  10 +-
 tests/testthat/test-explain.R  |  39 +++++++
 tests/testthat/test-recipes.R  | 188 +++++++++++++++++++++++++++++++++
 tests/testthat/test-spending.R |  15 +++
 tests/testthat/test-views.R    |  23 ++++
 15 files changed, 751 insertions(+), 16 deletions(-)
 create mode 100644 R/recipes.R
 create mode 100644 R/series_breaks.R
 create mode 100644 R/suggestions.R
 create mode 100644 man/cog_recipes.Rd
 create mode 100644 tests/testthat/test-recipes.R

diff --git a/NAMESPACE b/NAMESPACE
index 19baa13..1c67f0b 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -10,5 +10,6 @@ export(cog_gov_search)
 export(cog_manifest)
 export(cog_mirror)
 export(cog_peer_compare)
+export(cog_recipes)
 export(cog_revenue)
 export(cog_spending)
diff --git a/R/explain.R b/R/explain.R
index 0cec305..2f2d44b 100644
--- a/R/explain.R
+++ b/R/explain.R
@@ -51,6 +51,15 @@ cog_explain <- function(result, format = c("print", "list")) {
     cli::cli_text("Category: (all)")
   }
 
+  if (!is.null(prov$basis)) {
+    note <- if (!is.null(prov$basis_note) && !is.na(prov$basis_note)) {
+      sprintf(" (%s)", prov$basis_note)
+    } else {
+      ""
+    }
+    cli::cli_text("Basis: {prov$basis}{note}")
+  }
+
   cli::cli_h2("Codes observed")
   codes <- prov$codes_summed$observed
   if (length(codes) == 0L) {
@@ -66,6 +75,39 @@ cog_explain <- function(result, format = c("print", "list")) {
     )
   }
 
+  h <- prov$harmonization
+  if (!is.null(h) && isTRUE(h$applied)) {
+    cli::cli_h2("Harmonization")
+    cli::cli_text(
+      "Excluded {h$na_rows_excluded} row(s) with no harmonized_code (${format(h$na_amount_excluded, big.mark = ',')})"
+    )
+  }
+
+  rc <- prov$recipe
+  if (!is.null(rc)) {
+    cli::cli_h2("Recipe")
+    cli::cli_text("{rc$recipe_id}: {rc$label}")
+    comp_lines <- vapply(rc$components, function(x) {
+      sprintf("%s (%s, %s-%s, weight=%s)", x$component_code, x$gov_type_scope,
+              x$year_min, x$year_max, x$weight)
+    }, character(1))
+    cli::cli_ul(comp_lines)
+  }
+
+  if (length(prov$suggestions) > 0L) {
+    cli::cli_h2("Suggestions")
+    sugg_lines <- vapply(prov$suggestions, function(s) {
+      sprintf("%s -- %s (years %s-%s): %s", s$recipe_id, s$label,
+              s$available_years[1], s$available_years[2], s$hint)
+    }, character(1))
+    cli::cli_ul(sugg_lines)
+  }
+
+  if (length(prov$series_break_refs) > 0L) {
+    cli::cli_h2("Series breaks")
+    cli::cli_ul(.series_break_story_lines(prov$series_break_refs))
+  }
+
   cli::cli_h2("Transformations")
   uc <- prov$transformations$units_conversion
   if (isTRUE(uc$applied)) {
@@ -109,6 +151,28 @@ cog_explain <- function(result, format = c("print", "list")) {
   invisible(NULL)
 }
 
+# One "break-story" line per referenced break_id: "SB109 (2005): <join_advice>".
+# Re-queries series_breaks_pq for the detail (break_year, join_advice) that
+# provenance$series_break_refs deliberately doesn't carry (the schema keeps
+# that field to a plain id array). Falls back to bare ids if no session is
+# available (e.g. explaining a result after cog_close()) rather than
+# erroring cog_explain() over a cosmetic detail.
+#' @noRd
+.series_break_story_lines <- function(break_ids) {
+  con <- tryCatch(.ensure_session(), error = function(e) NULL)
+  if (is.null(con) || !DBI::dbIsValid(con)) return(break_ids)
+  detail <- tryCatch(
+    DBI::dbGetQuery(con, sprintf(
+      "SELECT break_id, break_year, join_advice FROM series_breaks_pq
+       WHERE break_id IN (%s) ORDER BY break_id",
+      .sql_lit_chr(break_ids)
+    )),
+    error = function(e) NULL
+  )
+  if (is.null(detail) || nrow(detail) == 0L) return(break_ids)
+  sprintf("%s (%s): %s", detail$break_id, detail$break_year, detail$join_advice)
+}
+
 # Expand a 2-digit Census popyear (e.g. 19) to a 4-digit calendar year (2019).
 # F-33 metadata stores popyear as 2 digits; pivot at 70 to handle a future
 # corpus that ever spans pre-1970 vintages, though current scope is 2000+.
diff --git a/R/provenance.R b/R/provenance.R
index fbd3cb0..bfd7a03 100644
--- a/R/provenance.R
+++ b/R/provenance.R
@@ -6,7 +6,8 @@
                               per_capita, adjust_to_year, result, sql,
                               subtype_col, basis = NA_character_,
                               basis_note = NA_character_,
-                              harmonization = NULL) {
+                              harmonization = NULL, recipe = NULL,
+                              suggestions = list()) {
   manifest <- .uscogdata_env$manifest
 
   codes <- result[["codes_included"]]
@@ -31,6 +32,14 @@
     unique(result$gov_name)
   }
 
+  schema_version <- suppressWarnings(as.integer(manifest$schema_version %||% 0L))
+  con <- .uscogdata_env$con
+  break_refs <- if (!is.null(con) && DBI::dbIsValid(con)) {
+    .build_series_break_refs(con, codes_observed, years, schema_version)
+  } else {
+    character(0)
+  }
+
   list(
     verb = verb,
     call = paste(deparse(call), collapse = " "),
@@ -46,6 +55,8 @@
       applied = FALSE, na_rows_excluded = 0L, na_amount_excluded = 0,
       note = NA_character_
     ),
+    recipe = recipe,
+    suggestions = suggestions,
     scope = list(
       gov_types_included = as.integer(unlist(manifest$scope$gov_types_included)),
       gov_types_excluded = as.integer(unlist(manifest$scope$gov_types_excluded)),
@@ -98,7 +109,7 @@
         index = if (is.null(adjust_to_year)) NA_character_ else "CPI-U (BLS CPIAUCSL annual average, bundled)"
       )
     ),
-    series_break_refs = character(0),
+    series_break_refs = break_refs,
     manifest = list(
       schema_version = as.integer(manifest$schema_version),
       pipeline_commit = manifest$pipeline_commit %||% NA_character_,
diff --git a/R/recipes.R b/R/recipes.R
new file mode 100644
index 0000000..11a55be
--- /dev/null
+++ b/R/recipes.R
@@ -0,0 +1,167 @@
+# R/recipes.R
+# Harmonization recipes: multi-code, cross-vintage series built by summing a
+# fixed set of component item codes with per-component weights and
+# year/gov-type scoping (see the `harmonization_recipes` view, registered
+# from data/harmonization_recipes.parquet, schema_version >= 5 only).
+#
+# Recipes exist because some cross-vintage series can't be expressed as a
+# 1:1 harmonized_code mapping (basis = "harmonized"): the wide era (pre-2012)
+# publishes only a combined aggregate row for these families (e.g.
+# corrections functions 04+05), while the modern era splits them into leaf
+# codes. A recipe's generic join sums whichever of its component codes are
+# present for a given year, so the resulting series is continuous across
+# that format boundary.
+
+#' List available harmonization recipes
+#'
+#' Recipes are multi-code cross-vintage series (see [cog_spending()]'s
+#' `recipe` argument) catalogued in the corpus's `harmonization_recipes`
+#' table. Use this to discover valid `recipe` ids.
+#'
+#' @param pattern Optional regex matched case-insensitively against
+#'   `recipe_id` or `label`.
+#' @return Tibble with columns `recipe_id`, `label`, `n_components`,
+#'   `year_min`, `year_max` (the min/max component year coverage), sorted by
+#'   `recipe_id`.
+#' @export
+cog_recipes <- function(pattern = NULL) {
+  if (!is.null(pattern) &&
+      (!is.character(pattern) || length(pattern) != 1L)) {
+    cli::cli_abort("`pattern` must be a length-1 character string or NULL.")
+  }
+  con <- .ensure_session()
+  .require_schema_v5(con, .uscogdata_env$manifest, "cog_recipes()")
+
+  where <- if (is.null(pattern)) {
+    ""
+  } else {
+    sprintf(
+      "WHERE regexp_matches(recipe_id, %1$s, 'i') OR regexp_matches(label, %1$s, 'i')",
+      .sql_lit_chr(pattern)
+    )
+  }
+  sql <- paste(
+    "SELECT recipe_id, any_value(label) AS label,
+            COUNT(*) AS n_components,
+            MIN(year_min) AS year_min, MAX(year_max) AS year_max
+     FROM harmonization_recipes",
+    where,
+    "GROUP BY recipe_id
+     ORDER BY recipe_id"
+  )
+  out <- tibble::as_tibble(DBI::dbGetQuery(con, sql))
+  out$year_min <- as.integer(out$year_min)
+  out$year_max <- as.integer(out$year_max)
+  out$n_components <- as.integer(out$n_components)
+  out
+}
+
+#' Abort unless the active corpus has schema_version >= 5.
+#' @noRd
+.require_schema_v5 <- function(con, manifest, what) {
+  sv <- suppressWarnings(as.integer(manifest$schema_version %||% 0L))
+  if (sv < 5L) {
+    cli::cli_abort(c(
+      sprintf("%s requires corpus schema_version >= 5.", what),
+      x = "Active corpus has schema_version {sv}.",
+      i = "Point USCOGDATA_URL at a schema_version >= 5 corpus to use harmonization recipes."
+    ), class = "uscogdata_schema_unsupported")
+  }
+  invisible(sv)
+}
+
+#' Abort with the valid id list unless `recipe_id` exists in the catalog.
+#' @noRd
+.validate_recipe_id <- function(con, recipe_id) {
+  ids <- DBI::dbGetQuery(
+    con, "SELECT DISTINCT recipe_id FROM harmonization_recipes"
+  )$recipe_id
+  if (!recipe_id %in% ids) {
+    cli::cli_abort(c(
+      "Unknown recipe = {.val {recipe_id}}.",
+      i = "Valid ids: {paste(sort(ids), collapse = ', ')}",
+      i = "See cog_recipes() for labels and year coverage."
+    ), class = "uscogdata_unknown_recipe")
+  }
+  invisible(TRUE)
+}
+
+#' Fetch the component rows for one recipe (label, component codes, scope,
+#' year ranges, weights) -- both for running the recipe and for the
+#' `recipe` provenance block.
+#' @noRd
+.recipe_components <- function(con, recipe_id) {
+  sql <- sprintf(
+    "SELECT recipe_id, label, component_code, gov_type_scope,
+            year_min, year_max, weight, source_break_ids, notes
+     FROM harmonization_recipes
+     WHERE recipe_id = %s
+     ORDER BY component_code",
+    .sql_lit_chr(recipe_id)
+  )
+  tibble::as_tibble(DBI::dbGetQuery(con, sql))
+}
+
+#' Run a recipe's generic join: sum `amt * weight` across whichever
+#' component codes are present for each (year, canonical_govid), scoped by
+#' gov_type_scope. Deliberately does NOT filter `NOT is_aggregate`: in the
+#' wide era (<= 2011) these families' component codes exist ONLY as
+#' aggregate rows (leaves first appear 2012), so excluding aggregates would
+#' zero out the wide-era half of every recipe. This is safe by corpus
+#' construction -- wide-era rows for these codes are aggregate-only, modern
+#' rows are leaf-only, and every component row is year-scoped via
+#' `year_min`/`year_max` -- so there is no double-counting. (Checkpoint
+#' review docs/phase_r_harmonization_review.md § 0.2.)
+#' @noRd
+.run_recipe <- function(con, recipe_id, govid, years) {
+  sql <- sprintf(
+    "SELECT l.year, l.canonical_govid,
+            COALESCE(x.gov_name, l.gov_name) AS gov_name,
+            SUM(l.amt * r.weight) * 1000.0 AS amt_nominal,
+            string_agg(DISTINCT l.item_code, ',' ORDER BY l.item_code) AS codes_included
+     FROM long l
+     JOIN harmonization_recipes r
+       ON l.item_code = r.component_code
+      AND l.year BETWEEN r.year_min AND r.year_max
+      AND (r.gov_type_scope = 'all'
+           OR (r.gov_type_scope = 'state' AND l.type = 0)
+           OR (r.gov_type_scope = 'local' AND l.type BETWEEN 1 AND 3))
+     LEFT JOIN canonical_fips_xwalk x USING (canonical_govid)
+     WHERE r.recipe_id = %1$s
+       AND l.canonical_govid IN (%2$s)
+       AND l.year IN (%3$s)
+     GROUP BY 1, 2, 3
+     ORDER BY 1, 2",
+    .sql_lit_chr(recipe_id), .sql_lit_chr(govid),
+    paste(as.integer(years), collapse = ",")
+  )
+  result <- tibble::as_tibble(DBI::dbGetQuery(con, sql))
+  attr(result, "sql_query") <- sql
+  result
+}
+
+#' Shape a raw .run_recipe() result into the standard cog_spending()/
+#' cog_revenue() column layout: subtype = "recipe", category = the recipe's
+#' label, aggregate_fallback = FALSE (recipes resolve coverage gaps by
+#' construction, not by falling back to an aggregate row).
+#' @noRd
+.shape_recipe_result <- function(result, subtype_col, label) {
+  sql_query <- attr(result, "sql_query")
+  n <- nrow(result)
+  result[[subtype_col]] <- rep("recipe", n)
+  result$category <- rep(label, n)
+  result$aggregate_fallback <- rep(FALSE, n)
+  result <- result[, c(
+    "year", "canonical_govid", "gov_name", subtype_col, "category",
+    "amt_nominal", "codes_included", "aggregate_fallback"
+  ), drop = FALSE]
+  attr(result, "sql_query") <- sql_query
+  result
+}
+
+#' Turn a small data.frame into a list-of-lists (one list per row), the
+#' shape used for the `recipe$components` provenance block.
+#' @noRd
+.df_to_row_list <- function(df) {
+  lapply(seq_len(nrow(df)), function(i) as.list(df[i, , drop = FALSE]))
+}
diff --git a/R/revenue.R b/R/revenue.R
index 5e94d9a..ed71d08 100644
--- a/R/revenue.R
+++ b/R/revenue.R
@@ -15,7 +15,7 @@
 #' @export
 cog_revenue <- function(govid, years, category = NULL,
                         per_capita = FALSE, adjust_to_year = NULL,
-                        basis = c("harmonized", "raw")) {
+                        basis = c("harmonized", "raw"), recipe = NULL) {
   .verb_spendrev(
     verb           = "cog_revenue",
     view_base      = "revenue_annotated",
@@ -27,6 +27,7 @@ cog_revenue <- function(govid, years, category = NULL,
     category       = category,
     per_capita     = per_capita,
     adjust_to_year = adjust_to_year,
-    basis          = basis
+    basis          = basis,
+    recipe         = recipe
   )
 }
diff --git a/R/series_breaks.R b/R/series_breaks.R
new file mode 100644
index 0000000..d4f0c1c
--- /dev/null
+++ b/R/series_breaks.R
@@ -0,0 +1,22 @@
+# R/series_breaks.R
+# Populates prov$series_break_refs (schema in inst/schemas/provenance-v1.json
+# defines the field; it was always present but always empty pre-Phase-R2)
+# with the ids of any catalogued series break whose fin_code appears among
+# the result's observed item codes and whose break_year falls inside the
+# requested year span -- the "break warnings in the provenance envelope"
+# spec § 5 promises downstream consumers (cog-api passes provenance through
+# verbatim). schema_version >= 5 only: series_breaks_pq isn't registered on
+# an older corpus.
+
+#' @noRd
+.build_series_break_refs <- function(con, codes_observed, years, schema_version) {
+  if (schema_version < 5L || length(codes_observed) == 0L) return(character(0))
+  sql <- sprintf(
+    "SELECT DISTINCT break_id
+     FROM series_breaks_pq
+     WHERE fin_code IN (%s) AND break_year BETWEEN %d AND %d
+     ORDER BY break_id",
+    .sql_lit_chr(codes_observed), min(as.integer(years)), max(as.integer(years))
+  )
+  DBI::dbGetQuery(con, sql)$break_id
+}
diff --git a/R/spending.R b/R/spending.R
index 8526103..70582b6 100644
--- a/R/spending.R
+++ b/R/spending.R
@@ -29,6 +29,12 @@
 #'   tables), `basis` silently resolves to `"raw"` when left at its default
 #'   and the resolution is recorded in the provenance; explicitly passing
 #'   `basis = "harmonized"` on such a corpus aborts.
+#' @param recipe Optional harmonization recipe id (see [cog_recipes()]) for
+#'   multi-code cross-vintage series that a 1:1 harmonized_code mapping
+#'   can't express (e.g. a wide-era aggregate that only splits into leaf
+#'   codes in the modern era). Mutually exclusive with `category`. The
+#'   result's subtype column reads `"recipe"` and `category` reads the
+#'   recipe's label. Requires `schema_version >= 5`.
 #' @return Tibble with columns `year`, `canonical_govid`, `gov_name`,
 #'   `spend_subtype`, `category`, `amt_nominal`, optional `amt_real`,
 #'   optional `amt_per_capita_nominal`, optional `amt_per_capita_real`,
@@ -37,7 +43,7 @@
 #' @export
 cog_spending <- function(govid, years, category = NULL,
                          per_capita = FALSE, adjust_to_year = NULL,
-                         basis = c("harmonized", "raw")) {
+                         basis = c("harmonized", "raw"), recipe = NULL) {
   .verb_spendrev(
     verb          = "cog_spending",
     view_base     = "spending_annotated",
@@ -49,7 +55,8 @@ cog_spending <- function(govid, years, category = NULL,
     category      = category,
     per_capita    = per_capita,
     adjust_to_year = adjust_to_year,
-    basis         = basis
+    basis         = basis,
+    recipe        = recipe
   )
 }
 
@@ -57,12 +64,13 @@ cog_spending <- function(govid, years, category = NULL,
 .verb_spendrev <- function(verb, view_base, subtype_col, flow_prefixes, call,
                            govid, years, category,
                            per_capita, adjust_to_year,
-                           basis = c("harmonized", "raw")) {
+                           basis = c("harmonized", "raw"), recipe = NULL) {
   basis_explicit <- length(basis) == 1L
   basis <- match.arg(basis, c("harmonized", "raw"))
 
   govid <- .coerce_govid_input(govid, arg = "govid")
-  .validate_verb_inputs(govid, years, category, per_capita, adjust_to_year)
+  .validate_verb_inputs(govid, years, category, per_capita, adjust_to_year,
+                        recipe)
 
   years   <- as.integer(years)
   if (!is.null(adjust_to_year)) adjust_to_year <- as.integer(adjust_to_year)
@@ -73,9 +81,26 @@ cog_spending <- function(govid, years, category = NULL,
 
   resolved <- .resolve_basis(basis, basis_explicit, manifest)
 
-  view <- .select_view(view_base, resolved$basis)
-  sql <- .build_verb_sql(view, subtype_col, govid, years, category)
-  result <- tibble::as_tibble(DBI::dbGetQuery(con, sql))
+  recipe_block <- NULL
+  category_for_prov <- category
+  if (!is.null(recipe)) {
+    .require_schema_v5(con, manifest, "recipe =")
+    .validate_recipe_id(con, recipe)
+    comps <- .recipe_components(con, recipe)
+    recipe_label <- comps$label[[1]]
+    result <- .run_recipe(con, recipe, govid, years)
+    sql <- attr(result, "sql_query")
+    result <- .shape_recipe_result(result, subtype_col, recipe_label)
+    recipe_block <- list(
+      recipe_id = recipe, label = recipe_label,
+      components = .df_to_row_list(comps)
+    )
+    category_for_prov <- recipe_label
+  } else {
+    view <- .select_view(view_base, resolved$basis)
+    sql <- .build_verb_sql(view, subtype_col, govid, years, category)
+    result <- tibble::as_tibble(DBI::dbGetQuery(con, sql))
+  }
 
   if (per_capita) result <- .attach_per_capita(result, con, govid)
   if (!is.null(adjust_to_year)) {
@@ -88,12 +113,18 @@ cog_spending <- function(govid, years, category = NULL,
     con, govid, years, resolved, flow_prefixes
   )
 
+  suggestions <- if (is.null(recipe)) {
+    .build_suggestions(con, govid, years, category, result, resolved$basis)
+  } else {
+    list()
+  }
+
   prov <- .build_provenance(
     verb           = verb,
     call           = call,
     govid          = govid,
     years          = years,
-    category       = category,
+    category       = category_for_prov,
     per_capita     = per_capita,
     adjust_to_year = adjust_to_year,
     result         = result,
@@ -101,18 +132,23 @@ cog_spending <- function(govid, years, category = NULL,
     subtype_col    = subtype_col,
     basis          = resolved$basis,
     basis_note     = resolved$note,
-    harmonization  = harmonization
+    harmonization  = harmonization,
+    recipe         = recipe_block,
+    suggestions    = suggestions
   )
   prov$scope$govids_found   <- scope$found
   prov$scope$govids_missing <- scope$missing
   attr(result, "provenance") <- prov
   attr(result, ".popyear_range") <- NULL
+
+  if (length(suggestions) > 0L) .inform_suggestions(suggestions)
+
   result
 }
 
 #' @noRd
 .validate_verb_inputs <- function(govid, years, category,
-                                  per_capita, adjust_to_year) {
+                                  per_capita, adjust_to_year, recipe = NULL) {
   if (!is.character(govid) || length(govid) == 0L) {
     cli::cli_abort("`govid` must be a non-empty character vector.")
   }
@@ -131,6 +167,17 @@ cog_spending <- function(govid, years, category = NULL,
       cli::cli_abort("`adjust_to_year` must be NULL or a length-1 integer.")
     }
   }
+  if (!is.null(recipe)) {
+    if (!is.character(recipe) || length(recipe) != 1L) {
+      cli::cli_abort("`recipe` must be NULL or a length-1 character string.")
+    }
+    if (!is.null(category)) {
+      cli::cli_abort(c(
+        "`recipe` and `category` are mutually exclusive.",
+        i = "Pass one or the other, not both."
+      ), class = "uscogdata_recipe_category_conflict")
+    }
+  }
   invisible(TRUE)
 }
 
diff --git a/R/suggestions.R b/R/suggestions.R
new file mode 100644
index 0000000..fc59d21
--- /dev/null
+++ b/R/suggestions.R
@@ -0,0 +1,119 @@
+# R/suggestions.R
+# Recipe-component-driven signposting: when a basis = "harmonized" query for
+# a category comes back with a coverage gap in some requested years (the
+# result has no rows at all in that year) that a harmonization recipe would
+# actually fill for this government, surface that recipe as a suggestion.
+#
+# This is deliberately keyed off the recipe catalog's component codes, not
+# off harmonization_map rows: no live map row carries a non-blank
+# suggested_recipe_id (the corpus's wide era exposes split families like
+# corrections functions 04+05 ONLY as aggregate rows, which basis =
+# "harmonized" excludes by construction -- there's no NA ruling to hang a
+# suggestion off of, just a leaf-code absence a recipe happens to fill).
+# See docs/phase_r_harmonization_review.md § 0.3.
+#
+# Scope is deliberately narrow: signposting only runs when the caller
+# supplied a `category` (an un-scoped, all-categories query has no single
+# coverage question to answer) and only flags a recipe when the ACTUAL
+# result has zero rows in a requested year AND the candidate recipe's own
+# generic join (same join .run_recipe() uses, including its wide-era
+# aggregate rows) produces at least one row for this government in that
+# year. Checking presence per-government (not corpus-wide) avoids false
+# positives from ordinary reporting variance -- most governments don't use
+# every sibling code in a multi-code category every year, and that is not
+# a format-boundary gap worth signposting.
+
+#' Build the `prov$suggestions` list for a (non-recipe) basis = "harmonized"
+#' verb call: recipes whose generic join would fill a real gap in `result`.
+#'
+#' @param con Active DuckDB connection.
+#' @param govid Character vector of canonical_govid values (the verb's raw
+#'   `govid`).
+#' @param years Integer vector of requested years.
+#' @param category `category` argument as passed to the verb (character
+#'   vector or `NULL`; suggestions are only computed when non-NULL).
+#' @param result The verb's already-computed result tibble (post basis
+#'   query, pre per_capita/adjust_to_year).
+#' @param basis The *resolved* basis (`"harmonized"` or `"raw"`).
+#' @return List of `list(recipe_id, label, available_years, hint)`, possibly
+#'   empty.
+#' @noRd
+.build_suggestions <- function(con, govid, years, category, result, basis) {
+  if (!identical(basis, "harmonized") || is.null(category)) return(list())
+
+  candidates <- DBI::dbGetQuery(con, sprintf(
+    "SELECT DISTINCT recipe_id FROM harmonization_recipes
+     WHERE component_code IN (
+       SELECT DISTINCT item_code FROM summary_categories WHERE category IN (%s)
+     )",
+    .sql_lit_chr(category)
+  ))$recipe_id
+  if (length(candidates) == 0L) return(list())
+
+  result_years <- if (is.null(result) || nrow(result) == 0L) {
+    integer(0)
+  } else {
+    unique(as.integer(result$year))
+  }
+  gap_years <- setdiff(as.integer(years), result_years)
+  if (length(gap_years) == 0L) return(list())
+
+  meta <- tibble::as_tibble(DBI::dbGetQuery(con, sprintf(
+    "SELECT recipe_id, any_value(label) AS label,
+            MIN(year_min) AS year_min, MAX(year_max) AS year_max
+     FROM harmonization_recipes
+     WHERE recipe_id IN (%s)
+     GROUP BY recipe_id",
+    .sql_lit_chr(candidates)
+  )))
+
+  # Which (recipe_id, year) pairs the recipe's own generic join actually
+  # covers for this government, restricted to the gap years -- the same
+  # join .run_recipe() uses (component year_min/year_max + gov_type_scope,
+  # no is_aggregate filter), just checking existence instead of summing.
+  covered <- DBI::dbGetQuery(con, sprintf(
+    "SELECT DISTINCT r.recipe_id, l.year
+     FROM long l
+     JOIN harmonization_recipes r
+       ON l.item_code = r.component_code
+      AND l.year BETWEEN r.year_min AND r.year_max
+      AND (r.gov_type_scope = 'all'
+           OR (r.gov_type_scope = 'state' AND l.type = 0)
+           OR (r.gov_type_scope = 'local' AND l.type BETWEEN 1 AND 3))
+     WHERE r.recipe_id IN (%s)
+       AND l.canonical_govid IN (%s)
+       AND l.year IN (%s)",
+    .sql_lit_chr(candidates), .sql_lit_chr(govid),
+    paste(gap_years, collapse = ",")
+  ))
+
+  suggestions <- list()
+  for (rid in candidates) {
+    if (!rid %in% covered$recipe_id) next
+    m <- meta[meta$recipe_id == rid, ]
+    suggestions[[length(suggestions) + 1L]] <- list(
+      recipe_id = rid,
+      label = m$label[[1]],
+      available_years = c(as.integer(m$year_min), as.integer(m$year_max)),
+      hint = sprintf("re-run with recipe = '%s'", rid)
+    )
+  }
+  suggestions
+}
+
+#' Emit the single cli::cli_inform() message summarizing all suggestions
+#' for a verb call (the brief's "one message", not one per suggestion).
+#' Bullet text is pre-formatted plain text (no cli/glue `{}` markup) since
+#' recipe ids/labels are untrusted-ish data values, not literal call-site
+#' expressions.
+#' @noRd
+.inform_suggestions <- function(suggestions) {
+  bullets <- vapply(suggestions, function(s) {
+    sprintf("%s (%d-%d): %s", s$recipe_id,
+            s$available_years[1], s$available_years[2], s$hint)
+  }, character(1))
+  cli::cli_inform(c(
+    i = "Coverage gap detected for the requested years; a harmonization recipe may fill it:",
+    stats::setNames(bullets, rep("*", length(bullets)))
+  ))
+}
diff --git a/man/cog_recipes.Rd b/man/cog_recipes.Rd
new file mode 100644
index 0000000..149fb76
--- /dev/null
+++ b/man/cog_recipes.Rd
@@ -0,0 +1,22 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/recipes.R
+\name{cog_recipes}
+\alias{cog_recipes}
+\title{List available harmonization recipes}
+\usage{
+cog_recipes(pattern = NULL)
+}
+\arguments{
+\item{pattern}{Optional regex matched case-insensitively against
+`recipe_id` or `label`.}
+}
+\value{
+Tibble with columns `recipe_id`, `label`, `n_components`,
+  `year_min`, `year_max` (the min/max component year coverage), sorted by
+  `recipe_id`.
+}
+\description{
+Recipes are multi-code cross-vintage series (see [cog_spending()]'s
+`recipe` argument) catalogued in the corpus's `harmonization_recipes`
+table. Use this to discover valid `recipe` ids.
+}
diff --git a/man/cog_revenue.Rd b/man/cog_revenue.Rd
index dd1a5e9..18b77df 100644
--- a/man/cog_revenue.Rd
+++ b/man/cog_revenue.Rd
@@ -10,7 +10,8 @@ cog_revenue(
   category = NULL,
   per_capita = FALSE,
   adjust_to_year = NULL,
-  basis = c("harmonized", "raw")
+  basis = c("harmonized", "raw"),
+  recipe = NULL
 )
 }
 \arguments{
@@ -40,6 +41,13 @@ folding). On a corpus with `schema_version < 5` (no harmonization
 tables), `basis` silently resolves to `"raw"` when left at its default
 and the resolution is recorded in the provenance; explicitly passing
 `basis = "harmonized"` on such a corpus aborts.}
+
+\item{recipe}{Optional harmonization recipe id (see [cog_recipes()]) for
+multi-code cross-vintage series that a 1:1 harmonized_code mapping
+can't express (e.g. a wide-era aggregate that only splits into leaf
+codes in the modern era). Mutually exclusive with `category`. The
+result's subtype column reads `"recipe"` and `category` reads the
+recipe's label. Requires `schema_version >= 5`.}
 }
 \value{
 Tibble with columns `year`, `canonical_govid`, `gov_name`,
diff --git a/man/cog_spending.Rd b/man/cog_spending.Rd
index 876a48f..8e4c52a 100644
--- a/man/cog_spending.Rd
+++ b/man/cog_spending.Rd
@@ -10,7 +10,8 @@ cog_spending(
   category = NULL,
   per_capita = FALSE,
   adjust_to_year = NULL,
-  basis = c("harmonized", "raw")
+  basis = c("harmonized", "raw"),
+  recipe = NULL
 )
 }
 \arguments{
@@ -40,6 +41,13 @@ folding). On a corpus with `schema_version < 5` (no harmonization
 tables), `basis` silently resolves to `"raw"` when left at its default
 and the resolution is recorded in the provenance; explicitly passing
 `basis = "harmonized"` on such a corpus aborts.}
+
+\item{recipe}{Optional harmonization recipe id (see [cog_recipes()]) for
+multi-code cross-vintage series that a 1:1 harmonized_code mapping
+can't express (e.g. a wide-era aggregate that only splits into leaf
+codes in the modern era). Mutually exclusive with `category`. The
+result's subtype column reads `"recipe"` and `category` reads the
+recipe's label. Requires `schema_version >= 5`.}
 }
 \value{
 Tibble with columns `year`, `canonical_govid`, `gov_name`,
diff --git a/tests/testthat/test-explain.R b/tests/testthat/test-explain.R
index 83f18ab..e824807 100644
--- a/tests/testthat/test-explain.R
+++ b/tests/testthat/test-explain.R
@@ -31,6 +31,45 @@ test_that("cog_explain errors on non-verb input", {
   expect_error(cog_explain(df), "provenance")
 })
 
+test_that("cog_explain prints basis + harmonization block", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", 2020L, "Corrections")
+  txt <- paste(c(
+    capture.output(cog_explain(r)),
+    capture.output(cog_explain(r), type = "message")
+  ), collapse = "\n")
+  expect_true(grepl("Basis: harmonized", txt))
+  expect_true(grepl("Harmonization", txt))
+  expect_true(grepl("Excluded 0 row", txt))
+})
+
+test_that("cog_explain prints a Recipe section for recipe = results", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", c(2011L, 2012L), recipe = "corrections_combined")
+  txt <- paste(c(
+    capture.output(cog_explain(r)),
+    capture.output(cog_explain(r), type = "message")
+  ), collapse = "\n")
+  expect_true(grepl("Recipe", txt))
+  expect_true(grepl("corrections_combined", txt))
+  expect_true(grepl("E04", txt))
+  expect_true(grepl("E05", txt))
+})
+
+test_that("cog_explain prints a Suggestions section when the provenance has one", {
+  skip_if_no_corpus()
+  r <- suppressMessages(
+    cog_spending("121011212191", c(2011L, 2012L), category = "Corrections")
+  )
+  txt <- paste(c(
+    capture.output(cog_explain(r)),
+    capture.output(cog_explain(r), type = "message")
+  ), collapse = "\n")
+  expect_true(grepl("Suggestions", txt))
+  expect_true(grepl("corrections_combined", txt))
+  expect_true(grepl("re-run with recipe", txt))
+})
+
 test_that("cog_explain prints denominator + popyear_range + counts", {
   skip_if_no_corpus()
   with_fixture_corpus({
diff --git a/tests/testthat/test-recipes.R b/tests/testthat/test-recipes.R
new file mode 100644
index 0000000..44a1bf3
--- /dev/null
+++ b/tests/testthat/test-recipes.R
@@ -0,0 +1,188 @@
+# tests/testthat/test-recipes.R
+#
+# cog_recipes(), recipe = in cog_spending()/cog_revenue(), and the
+# recipe-component-driven signposting in prov$suggestions (Phase R2 /
+# Task 11, schema_version 5).
+
+test_that("cog_recipes lists the curated catalog including corrections_combined", {
+  skip_if_no_corpus()
+  r <- cog_recipes()
+  expect_s3_class(r, "tbl_df")
+  expect_equal(names(r), c("recipe_id", "label", "n_components", "year_min", "year_max"))
+  expect_equal(nrow(r), 24L)
+  expect_true("corrections_combined" %in% r$recipe_id)
+  expect_true("t19_selective_sales_wide" %in% r$recipe_id)
+  expect_true("ig_federal_b89_wide" %in% r$recipe_id)
+  expect_true("rents_royalties_u4_wide" %in% r$recipe_id)
+  expect_true("higher_ed_e18_wide" %in% r$recipe_id)
+  expect_true("cash_securities_z77_wide" %in% r$recipe_id)
+  # Superseded id from the pre-curation brief text must NOT be present.
+  expect_false("corrections_judicial_combined" %in% r$recipe_id)
+})
+
+test_that("cog_recipes(pattern=) filters by recipe_id or label", {
+  skip_if_no_corpus()
+  r <- cog_recipes("corrections")
+  expect_true(nrow(r) >= 1L)
+  expect_true(all(grepl("corrections", r$recipe_id, ignore.case = TRUE) |
+                    grepl("corrections", r$label, ignore.case = TRUE)))
+})
+
+test_that("cog_recipes requires schema_version >= 5", {
+  skip_if_no_corpus()
+  with_doctored_schema_version(4L, {
+    expect_error(cog_recipes(), class = "uscogdata_schema_unsupported")
+  })
+})
+
+# --- recipe = : generic join, no is_aggregate filter -----------------------
+
+test_that("recipe = 'corrections_combined' is continuous across the 2011->2012 seam", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", years = c(2011L, 2012L),
+                    recipe = "corrections_combined")
+  expect_equal(nrow(r), 2L)
+  expect_true(all(c("year", "canonical_govid", "gov_name", "spend_subtype",
+                    "category", "amt_nominal", "codes_included",
+                    "aggregate_fallback", "notes") %in% names(r)))
+  expect_equal(unique(r$spend_subtype), "recipe")
+  expect_equal(unique(r$category), "Corrections (functions 04+05 combined)")
+  expect_false(any(r$aggregate_fallback))
+
+  r2011 <- r$amt_nominal[r$year == 2011L]
+  r2012 <- r$amt_nominal[r$year == 2012L]
+  # 2011: E05 only exists as a wide-era AGGREGATE row (is_aggregate = TRUE)
+  # for Broward -- data-verified $216,088,000. Since .run_recipe() does NOT
+  # filter is_aggregate (amendment: the recipe join must not, because these
+  # families exist ONLY as aggregate rows in the wide era), the recipe
+  # correctly picks this up.
+  expect_equal(r2011, 216088000)
+  # 2012: modern E04 leaf ($213,056,000); Broward reports no E05 leaf that
+  # year, so the recipe total equals E04 alone -- still continuous with the
+  # 2011 aggregate, proving the wide-aggregate -> modern-leaf handoff.
+  expect_equal(r2012, 213056000)
+  expect_true(all(grepl("E04|E05", r$codes_included)))
+})
+
+test_that("recipe result carries a recipe provenance block with component rows", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", years = c(2011L, 2012L),
+                    recipe = "corrections_combined")
+  prov <- attr(r, "provenance")
+  expect_equal(prov$basis, "harmonized")
+  expect_equal(prov$category, "Corrections (functions 04+05 combined)")
+  expect_type(prov$recipe, "list")
+  expect_equal(prov$recipe$recipe_id, "corrections_combined")
+  expect_equal(prov$recipe$label, "Corrections (functions 04+05 combined)")
+  expect_length(prov$recipe$components, 2L)
+  comp_codes <- vapply(prov$recipe$components, function(x) x$component_code, character(1))
+  expect_setequal(comp_codes, c("E04", "E05"))
+  # A recipe query resolves its own coverage; it should never also carry
+  # suggestions for itself.
+  expect_length(prov$suggestions, 0L)
+})
+
+test_that("recipe = 't19_selective_sales_wide' sums the local T11/T14 legs when present", {
+  skip_if_no_corpus()
+  # Westminster City, CA (canonical_govid 082001211654): T11 = 0 in 2011,
+  # T11 = 568 (T14 = 0/absent) in 2012 -- a real, data-verified equality/
+  # inequality pair inside the amended fixture window (2011-2012), standing
+  # in for the brief's original 2004/2005 example (out of scope per the
+  # amended fixture years; the underlying local-tax-split boundary is
+  # nationally FY2005, but this government's own T11 reporting activates
+  # within our 2011-2012 window).
+  r <- cog_revenue("082001211654", years = c(2011L, 2012L),
+                   recipe = "t19_selective_sales_wide")
+
+  # Raw, single-code T19 total (not the "Other Taxes" category total, which
+  # would also sum in T11/T14/T21/T23/T27/T29/T53/T99 -- queried directly to
+  # isolate exactly the code the brief's equality/inequality check is about).
+  con <- uscogdata:::.ensure_session()
+  raw_t19 <- DBI::dbGetQuery(con, "
+    SELECT year, SUM(amt) * 1000.0 AS amt
+    FROM revenue_long
+    WHERE canonical_govid = '082001211654' AND item_code = 'T19'
+      AND year IN (2011, 2012)
+    GROUP BY year ORDER BY year
+  ")
+  raw_t19_2011 <- raw_t19$amt[raw_t19$year == 2011L]
+  raw_t19_2012 <- raw_t19$amt[raw_t19$year == 2012L]
+  expect_equal(raw_t19_2011, 2231000)
+  expect_equal(raw_t19_2012, 2365000)
+
+  recipe_2011 <- r$amt_nominal[r$year == 2011L]
+  recipe_2012 <- r$amt_nominal[r$year == 2012L]
+
+  expect_equal(recipe_2011, raw_t19_2011)       # equality: no local T11/T14 yet
+  expect_gt(recipe_2012, raw_t19_2012)          # inequality: local T11 joins in
+  expect_equal(recipe_2012, raw_t19_2012 + 568000)
+})
+
+test_that("recipe = and category = together aborts", {
+  skip_if_no_corpus()
+  expect_error(
+    cog_spending("121011212191", 2020L, category = "Corrections",
+                recipe = "corrections_combined"),
+    class = "uscogdata_recipe_category_conflict"
+  )
+})
+
+test_that("unknown recipe id aborts and lists valid ids", {
+  skip_if_no_corpus()
+  err <- tryCatch(
+    cog_spending("121011212191", 2020L, recipe = "does_not_exist"),
+    error = identity
+  )
+  expect_s3_class(err, "uscogdata_unknown_recipe")
+  expect_match(conditionMessage(err), "corrections_combined")
+})
+
+test_that("recipe = requires schema_version >= 5", {
+  skip_if_no_corpus()
+  with_doctored_schema_version(4L, {
+    expect_error(
+      cog_spending("121011212191", 2020L, recipe = "corrections_combined"),
+      class = "uscogdata_schema_unsupported"
+    )
+  })
+})
+
+# --- signposting -------------------------------------------------------
+
+test_that("signposting suggests corrections_combined across the 2011->2012 gap", {
+  skip_if_no_corpus()
+  expect_message(
+    r <- cog_spending("121011212191", years = c(2011L, 2012L),
+                      category = "Corrections"),
+    "recipe"
+  )
+  prov <- attr(r, "provenance")
+  expect_true(length(prov$suggestions) >= 1L)
+  ids <- vapply(prov$suggestions, function(s) s$recipe_id, character(1))
+  expect_true("corrections_combined" %in% ids)
+  hit <- prov$suggestions[[which(ids == "corrections_combined")]]
+  expect_equal(hit$hint, "re-run with recipe = 'corrections_combined'")
+  expect_equal(hit$available_years, c(1967L, 2023L))
+})
+
+test_that("no signposting when the result already has full year coverage", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", years = 2019:2020, category = "Corrections")
+  prov <- attr(r, "provenance")
+  expect_length(prov$suggestions, 0L)
+})
+
+test_that("no signposting when category is NULL (unscoped query)", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", years = c(2011L, 2012L))
+  prov <- attr(r, "provenance")
+  expect_length(prov$suggestions, 0L)
+})
+
+test_that("no signposting under basis = 'raw'", {
+  skip_if_no_corpus()
+  r <- cog_spending("121011212191", years = c(2011L, 2012L),
+                    category = "Corrections", basis = "raw")
+  prov <- attr(r, "provenance")
+  expect_length(prov$suggestions, 0L)
+})
diff --git a/tests/testthat/test-spending.R b/tests/testthat/test-spending.R
index d6a6c8b..b8e7c08 100644
--- a/tests/testthat/test-spending.R
+++ b/tests/testthat/test-spending.R
@@ -292,6 +292,21 @@ test_that("v4 corpus: explicit basis = 'harmonized' aborts", {
   })
 })
 
+test_that("provenance$series_break_refs is a populated-when-applicable character vector", {
+  skip_if_no_corpus()
+  with_fixture_corpus({
+    r <- cog_spending("121011212191", 2020L, "Corrections")
+    refs <- attr(r, "provenance")$series_break_refs
+    expect_type(refs, "character")
+    # No catalogued series_breaks_pq row falls inside this fixture's
+    # 2011/2012/2019/2020 window for the codes this query touches (E04/G04)
+    # -- data-verified; the mechanism itself is what's under test here, via
+    # a query-shaped unit test in test-views.R since the fixture has no
+    # positive case to pin against.
+    expect_equal(refs, character(0))
+  })
+})
+
 test_that("v4 corpus: explicit basis = 'raw' still works", {
   skip_if_no_corpus()
   with_doctored_schema_version(4L, {
diff --git a/tests/testthat/test-views.R b/tests/testthat/test-views.R
index 8cdd86d..fe30aad 100644
--- a/tests/testthat/test-views.R
+++ b/tests/testthat/test-views.R
@@ -51,6 +51,29 @@ test_that("the REPLACE(harmonized_code AS item_code) pattern folds a collapsed c
   DBI::dbExecute(con, "DROP TABLE synthetic_long")
 })
 
+test_that(".build_series_break_refs matches fin_code + break_year window", {
+  # No series_breaks_pq row falls inside the bundled fixture's 2011-2020
+  # window (data-verified; see the "series_break_refs" test in
+  # test-spending.R), so this proves the matching logic itself against the
+  # live view + a synthetic year window that DOES hit a cataloged break
+  # (SB075, fin_code E62, break_year 2005).
+  skip_if_no_corpus()
+  con <- cog_open()
+  on.exit(cog_close())
+  refs <- uscogdata:::.build_series_break_refs(
+    con, codes_observed = c("E62", "E04"), years = c(2003L, 2006L),
+    schema_version = 5L
+  )
+  expect_true("SB075" %in% refs)
+  expect_true("SB071" %in% refs)
+
+  # Gated on schema_version >= 5 even when the codes/years would otherwise match.
+  refs_v4 <- uscogdata:::.build_series_break_refs(
+    con, codes_observed = c("E62"), years = c(2003L, 2006L), schema_version = 4L
+  )
+  expect_equal(refs_v4, character(0))
+})
+
 test_that("schema v5 harmonization views register when the corpus supports them", {
   skip_if_no_corpus()
   con <- cog_open()