diff --git a/R/cpp_opts.R b/R/cpp_opts.R
index 3626f2e2..edf584eb 100644
--- a/R/cpp_opts.R
+++ b/R/cpp_opts.R
@@ -2,6 +2,7 @@
 
 # running and parsing exe info --------------------------------
 # run <model> info command
+#' @noRd
 #' @example `.cmdstan/bin`
 run_info_cli <- function(exe_file) {
   withr::with_path(
@@ -52,7 +53,7 @@ parse_exe_info_string <- function(ret_stdout) {
 model_compile_info <- function(exe_file, version) {
   info <- NULL
   if (version > "2.26.1") {
-    
+
     ret <- run_info_cli(exe_file)
     if (ret$status == 0) {
       info <- list()
diff --git a/R/fit.R b/R/fit.R
index bb14cbff..a2126a49 100644
--- a/R/fit.R
+++ b/R/fit.R
@@ -1501,12 +1501,15 @@ CmdStanMCMC <- R6::R6Class(
 #'   containing the pointwise log-likelihood. The default is to look for
 #'   `"log_lik"`. This argument is passed to the [`$draws()`][fit-method-draws]
 #'   method.
-#' @param r_eff (multiple options) How to handle the `r_eff` argument for `loo()`:
-#'   * `TRUE` (the default) will automatically call [loo::relative_eff.array()]
-#'   to compute the `r_eff` argument to pass to [loo::loo.array()].
-#'   * `FALSE` or `NULL` will avoid computing `r_eff` (which can sometimes be slow),
-#'   but the reported ESS and MCSE estimates can be over-optimistic if the
-#'   posterior draws are not (near) independent.
+#' @param r_eff (multiple options) How to handle the `r_eff` argument for
+#'   `loo()`. `r_eff` measures the amount of autocorrelation in MCMC draws, and
+#'   is used to compute more accurate ESS and MCSE estimates for pointwise and
+#'   total ELPDs.
+#'   * `TRUE` will call [loo::relative_eff.array()] to compute the `r_eff`
+#'   argument to pass to [loo::loo.array()].
+#'   * `FALSE` (the default) or `NULL` will avoid computing `r_eff`,
+#'   which can be very slow. The reported ESS and MCSE estimates may be
+#'   over-optimistic if the posterior draws are far from independent.
 #'   * If `r_eff` is anything else, that object will be passed as the `r_eff`
 #'   argument to [loo::loo.array()].
 #' @param moment_match (logical) Whether to use a
@@ -1537,7 +1540,7 @@ CmdStanMCMC <- R6::R6Class(
 #' print(loo_result)
 #' }
 #'
-loo <- function(variables = "log_lik", r_eff = TRUE, moment_match = FALSE, ...) {
+loo <- function(variables = "log_lik", r_eff = FALSE, moment_match = FALSE, ...) {
   require_suggested_package("loo")
   if (length(variables) != 1) {
     stop("Only a single variable name is allowed for the 'variables' argument.", call. = FALSE)
diff --git a/man/fit-method-loo.Rd b/man/fit-method-loo.Rd
index 8a63681a..d2ccb471 100644
--- a/man/fit-method-loo.Rd
+++ b/man/fit-method-loo.Rd
@@ -5,7 +5,7 @@
 \alias{loo}
 \title{Leave-one-out cross-validation (LOO-CV)}
 \usage{
-loo(variables = "log_lik", r_eff = TRUE, moment_match = FALSE, ...)
+loo(variables = "log_lik", r_eff = FALSE, moment_match = FALSE, ...)
 }
 \arguments{
 \item{variables}{(string) The name of the variable in the Stan program
@@ -13,13 +13,16 @@ containing the pointwise log-likelihood. The default is to look for
 \code{"log_lik"}. This argument is passed to the \code{\link[=fit-method-draws]{$draws()}}
 method.}
 
-\item{r_eff}{(multiple options) How to handle the \code{r_eff} argument for \code{loo()}:
+\item{r_eff}{(multiple options) How to handle the \code{r_eff} argument for
+\code{loo()}. \code{r_eff} measures the amount of autocorrelation in MCMC draws, and
+is used to compute more accurate ESS and MCSE estimates for pointwise and
+total ELPDs.
 \itemize{
-\item \code{TRUE} (the default) will automatically call \code{\link[loo:relative_eff]{loo::relative_eff.array()}}
-to compute the \code{r_eff} argument to pass to \code{\link[loo:loo]{loo::loo.array()}}.
-\item \code{FALSE} or \code{NULL} will avoid computing \code{r_eff} (which can sometimes be slow),
-but the reported ESS and MCSE estimates can be over-optimistic if the
-posterior draws are not (near) independent.
+\item \code{TRUE} will call \code{\link[loo:relative_eff]{loo::relative_eff.array()}} to compute the \code{r_eff}
+argument to pass to \code{\link[loo:loo]{loo::loo.array()}}.
+\item \code{FALSE} (the default) or \code{NULL} will avoid computing \code{r_eff},
+which can be very slow. The reported ESS and MCSE estimates may be
+over-optimistic if the posterior draws are far from independent.
 \item If \code{r_eff} is anything else, that object will be passed as the \code{r_eff}
 argument to \code{\link[loo:loo]{loo::loo.array()}}.
 }}