diff --git a/base/workflow/DESCRIPTION b/base/workflow/DESCRIPTION
index 1d0ca83bd70..942bb74ce54 100644
--- a/base/workflow/DESCRIPTION
+++ b/base/workflow/DESCRIPTION
@@ -48,5 +48,5 @@ Suggests:
     withr
 Copyright: Authors
 Encoding: UTF-8
-RoxygenNote: 7.3.3
 X-schema.org-keywords: PEcAn, data-assimilation, ecosystem-modeling, reproducibility
+Config/roxygen2/version: 8.0.0
diff --git a/base/workflow/NAMESPACE b/base/workflow/NAMESPACE
index c05f334c5d5..0f324aefd21 100644
--- a/base/workflow/NAMESPACE
+++ b/base/workflow/NAMESPACE
@@ -1,10 +1,13 @@
 # Generated by roxygen2: do not edit by hand
 
 export(do_conversions)
+export(insert_preprocess_result)
+export(preprocess_result)
 export(run.write.configs)
 export(runModule.get.trait.data)
 export(runModule.run.write.configs)
 export(runModule_start_model_runs)
 export(start_model_runs)
+export(validate_preprocess_result)
 importFrom(dplyr,"%>%")
 importFrom(rlang,"%||%")
diff --git a/base/workflow/R/preprocess_result.R b/base/workflow/R/preprocess_result.R
new file mode 100644
index 00000000000..f5ac3c84bc7
--- /dev/null
+++ b/base/workflow/R/preprocess_result.R
@@ -0,0 +1,140 @@
+#' Preprocessing Result Constructor
+#'
+#' Uniform return type for all preprocessing pipeline functions.
+#' Returns a named list that can be inserted directly into a PEcAn settings object.
+#' Disk-only for now; memory-primary path can be added later without breaking
+#' the interface.
+#'
+#' @param file Character. Path to the generated file.
+#' @param format Character. Format identifier (e.g., "CFmet", "ED2met").
+#' @param mimetype Character. MIME type of the file.
+#' @param dbfile.id Integer. BETY dbfile ID, if available. NULL if dbparms = NULL.
+#' @param start_date POSIXct. Start date of the data period.
+#' @param end_date POSIXct. End date of the data period.
+#' @param source Character. Data source identifier (e.g., "Ameriflux", "CRUNCEP").
+#'
+#' @return A named list with class attribute "preprocess_result" for potential
+#'   future subclassing, but behaves as a plain list for now.
+#'
+#' @examples
+#' result <- preprocess_result(
+#'   file = "/data/flux/US-NR1.2004.nc",
+#'   format = "CFmet",
+#'   mimetype = "application/x-netcdf",
+#'   dbfile.id = 12345,
+#'   start_date = as.POSIXct("2004-01-01"),
+#'   end_date = as.POSIXct("2004-12-31"),
+#'   source = "Ameriflux"
+#' )
+#'
+#' @md
+#' @export
+preprocess_result <- function(file, format, mimetype, dbfile.id = NULL,
+                              start_date = NULL, end_date = NULL, source = NULL) {
+  # Validation - using PEcAn.logger::logger.severe() for consistency with codebase
+  if (!is.character(file) || length(file) != 1) {
+    PEcAn.logger::logger.severe("file must be a single character path")
+  }
+  if (!file.exists(file)) {
+    PEcAn.logger::logger.warn("file does not exist:", file)
+  }
+  if (!is.character(format) || length(format) != 1) {
+    PEcAn.logger::logger.severe("format must be a single character string")
+  }
+  if (!is.character(mimetype) || length(mimetype) != 1) {
+    PEcAn.logger::logger.severe("mimetype must be a single character string")
+  }
+  if (!is.null(dbfile.id) && (!is.numeric(dbfile.id) || length(dbfile.id) != 1)) {
+    PEcAn.logger::logger.severe("dbfile.id must be a single integer or NULL")
+  }
+
+  result <- list(
+    file = file,
+    format = format,
+    mimetype = mimetype,
+    dbfile.id = dbfile.id,
+    start_date = start_date,
+    end_date = end_date,
+    source = source
+  )
+
+  # Class attribute for future subclassing, but no S3 methods yet
+  class(result) <- c("preprocess_result", "list")
+
+  result
+}
+
+#' Insert Preprocess Result into Settings
+#'
+#' Takes a preprocess_result (or list of them) and patches it into the
+#' appropriate location in a PEcAn settings object.
+#'
+#' @param settings List. PEcAn settings object.
+#' @param result preprocess_result or list of preprocess_result.
+#' @param input.type Character. Input type identifier, e.g., "met", "soil".
+#'
+#' @return Updated settings object.
+#'
+#' @md
+#' @export
+insert_preprocess_result <- function(settings, result, input.type) {
+  if (!is.list(result)) {
+    PEcAn.logger::logger.severe("result must be a list or preprocess_result")
+  }
+
+  # Handle single result or list of results
+  if (inherits(result, "preprocess_result")) {
+    result <- list(result)
+  }
+
+  # Ensure path exists in settings
+  if (is.null(settings$run$inputs)) {
+    settings$run$inputs <- list()
+  }
+  if (is.null(settings$run$inputs[[input.type]])) {
+    settings$run$inputs[[input.type]] <- list()
+  }
+
+  # Insert results
+  settings$run$inputs[[input.type]]$path <- sapply(result, `[[`, "file")
+  settings$run$inputs[[input.type]]$format <- result[[1]]$format
+  settings$run$inputs[[input.type]]$mimetype <- result[[1]]$mimetype
+
+  if (!is.null(result[[1]]$dbfile.id)) {
+    settings$run$inputs[[input.type]]$dbfile.id <- sapply(result, `[[`, "dbfile.id")
+  }
+
+  settings
+}
+
+#' Validate Preprocess Result
+#'
+#' Check that a preprocess_result has all required fields and valid values.
+#' Useful for parity tests and pipeline validation.
+#'
+#' @param result List. Object to validate.
+#' @param require.file.exists Logical. Whether to check file existence.
+#'
+#' @return Logical. TRUE if valid, throws error otherwise.
+#'
+#' @md
+#' @export
+validate_preprocess_result <- function(result, require.file.exists = TRUE) {
+  required_fields <- c("file", "format", "mimetype")
+
+  for (field in required_fields) {
+    if (is.null(result[[field]])) {
+      PEcAn.logger::logger.severe("Missing required field:", field)
+    }
+  }
+
+  if (!is.character(result$file) || length(result$file) != 1) {
+    PEcAn.logger::logger.severe("file must be a single character path")
+  }
+
+  if (require.file.exists && !file.exists(result$file)) {
+    PEcAn.logger::logger.severe("file does not exist:", result$file)
+  }
+
+  TRUE
+}
diff --git a/base/workflow/man/insert_preprocess_result.Rd b/base/workflow/man/insert_preprocess_result.Rd
new file mode 100644
index 00000000000..151f9914cca
--- /dev/null
+++ b/base/workflow/man/insert_preprocess_result.Rd
@@ -0,0 +1,22 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/preprocess_result.R
+\name{insert_preprocess_result}
+\alias{insert_preprocess_result}
+\title{Insert Preprocess Result into Settings}
+\usage{
+insert_preprocess_result(settings, result, input.type)
+}
+\arguments{
+\item{settings}{List. PEcAn settings object.}
+
+\item{result}{preprocess_result or list of preprocess_result.}
+
+\item{input.type}{Character. Input type identifier, e.g., "met", "soil".}
+}
+\value{
+Updated settings object.
+}
+\description{
+Takes a preprocess_result (or list of them) and patches it into the
+appropriate location in a PEcAn settings object.
+}
diff --git a/base/workflow/man/preprocess_result.Rd b/base/workflow/man/preprocess_result.Rd
new file mode 100644
index 00000000000..d4070711706
--- /dev/null
+++ b/base/workflow/man/preprocess_result.Rd
@@ -0,0 +1,53 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/preprocess_result.R
+\name{preprocess_result}
+\alias{preprocess_result}
+\title{Preprocessing Result Constructor}
+\usage{
+preprocess_result(
+  file,
+  format,
+  mimetype,
+  dbfile.id = NULL,
+  start_date = NULL,
+  end_date = NULL,
+  source = NULL
+)
+}
+\arguments{
+\item{file}{Character. Path to the generated file.}
+
+\item{format}{Character. Format identifier (e.g., "CFmet", "ED2met").}
+
+\item{mimetype}{Character. MIME type of the file.}
+
+\item{dbfile.id}{Integer. BETY dbfile ID, if available. NULL if dbparms = NULL.}
+
+\item{start_date}{POSIXct. Start date of the data period.}
+
+\item{end_date}{POSIXct. End date of the data period.}
+
+\item{source}{Character. Data source identifier (e.g., "Ameriflux", "CRUNCEP").}
+}
+\value{
+A named list with class attribute "preprocess_result" for potential
+future subclassing, but behaves as a plain list for now.
+}
+\description{
+Uniform return type for all preprocessing pipeline functions.
+Returns a named list that can be inserted directly into a PEcAn settings object.
+Disk-only for now; memory-primary path can be added later without breaking
+the interface.
+}
+\examples{
+result <- preprocess_result(
+  file = "/data/flux/US-NR1.2004.nc",
+  format = "CFmet",
+  mimetype = "application/x-netcdf",
+  dbfile.id = 12345,
+  start_date = as.POSIXct("2004-01-01"),
+  end_date = as.POSIXct("2004-12-31"),
+  source = "Ameriflux"
+)
+
+}
diff --git a/base/workflow/man/validate_preprocess_result.Rd b/base/workflow/man/validate_preprocess_result.Rd
new file mode 100644
index 00000000000..570a107c7e4
--- /dev/null
+++ b/base/workflow/man/validate_preprocess_result.Rd
@@ -0,0 +1,20 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/preprocess_result.R
+\name{validate_preprocess_result}
+\alias{validate_preprocess_result}
+\title{Validate Preprocess Result}
+\usage{
+validate_preprocess_result(result, require.file.exists = TRUE)
+}
+\arguments{
+\item{result}{List. Object to validate.}
+
+\item{require.file.exists}{Logical. Whether to check file existence.}
+}
+\value{
+Logical. TRUE if valid, throws error otherwise.
+}
+\description{
+Check that a preprocess_result has all required fields and valid values.
+Useful for parity tests and pipeline validation.
+}
diff --git a/base/workflow/tests/testthat/test-preprocess_result.R b/base/workflow/tests/testthat/test-preprocess_result.R
new file mode 100644
index 00000000000..66fe5e7e24a
--- /dev/null
+++ b/base/workflow/tests/testthat/test-preprocess_result.R
@@ -0,0 +1,101 @@
+
+context("Preprocess Result Constructor")
+
+test_that("preprocess_result creates valid object", {
+  tmpfile <- tempfile(fileext = ".nc")
+  file.create(tmpfile)
+  on.exit(unlink(tmpfile))
+
+  result <- preprocess_result(
+    file = tmpfile,
+    format = "CFmet",
+    mimetype = "application/x-netcdf",
+    dbfile.id = 12345,
+    start_date = as.POSIXct("2004-01-01"),
+    end_date = as.POSIXct("2004-12-31"),
+    source = "Ameriflux"
+  )
+
+  expect_type(result, "list")
+  expect_equal(result$file, tmpfile)
+  expect_equal(result$format, "CFmet")
+  expect_equal(result$dbfile.id, 12345)
+  expect_s3_class(result, "preprocess_result")
+  expect_s3_class(result, "list")
+})
+
+test_that("preprocess_result validates inputs with logger.severe", {
+  # logger.severe stops execution, so we expect error
+  expect_error(
+    preprocess_result(file = 123, format = "CFmet", mimetype = "application/x-netcdf"),
+    "file must be a single character path"
+  )
+
+  expect_error(
+    preprocess_result(file = "foo.nc", format = NULL, mimetype = "application/x-netcdf"),
+    "format must be a single character string"
+  )
+})
+
+test_that("preprocess_result accepts missing files", {
+  result <- preprocess_result(
+    file = "/nonexistent/file.nc",
+    format = "CFmet",
+    mimetype = "application/x-netcdf"
+  )
+  
+  expect_equal(result$file, "/nonexistent/file.nc")
+})
+
+test_that("insert_preprocess_result patches settings correctly", {
+  settings <- list(run = list(inputs = list()))
+  tmpfile <- tempfile(fileext = ".nc")
+  file.create(tmpfile)
+  on.exit(unlink(tmpfile))
+
+  result <- preprocess_result(
+    file = tmpfile,
+    format = "CFmet",
+    mimetype = "application/x-netcdf"
+  )
+
+  updated <- insert_preprocess_result(settings, result, "met")
+
+  expect_equal(updated$run$inputs$met$path, tmpfile)
+  expect_equal(updated$run$inputs$met$format, "CFmet")
+})
+
+test_that("insert_preprocess_result handles multiple results", {
+  settings <- list(run = list(inputs = list()))
+  tmpfile1 <- tempfile(fileext = ".nc")
+  tmpfile2 <- tempfile(fileext = ".nc")
+  file.create(tmpfile1)
+  file.create(tmpfile2)
+  on.exit({
+    unlink(tmpfile1)
+    unlink(tmpfile2)
+  })
+
+  results <- list(
+    preprocess_result(file = tmpfile1, format = "CFmet", mimetype = "application/x-netcdf"),
+    preprocess_result(file = tmpfile2, format = "CFmet", mimetype = "application/x-netcdf")
+  )
+
+  updated <- insert_preprocess_result(settings, results, "met")
+
+  expect_equal(updated$run$inputs$met$path, c(tmpfile1, tmpfile2))
+})
+
+test_that("validate_preprocess_result catches invalid results", {
+  expect_error(
+    validate_preprocess_result(list(format = "CFmet")),
+    "Missing required field: file"
+  )
+
+  tmpfile <- tempfile()
+  file.create(tmpfile)
+  on.exit(unlink(tmpfile))
+
+  valid <- preprocess_result(file = tmpfile, format = "CFmet", mimetype = "application/x-netcdf")
+  expect_true(validate_preprocess_result(valid))
+})
\ No newline at end of file