diff --git a/.github/workflows/comment_bot.yml b/.github/workflows/comment_bot.yml
index d501d971311..c7d11c25ca3 100644
--- a/.github/workflows/comment_bot.yml
+++ b/.github/workflows/comment_bot.yml
@@ -25,9 +25,9 @@ on:
       - edited
 
 jobs:
-
-  listen:
+  crossbow:
     name: Listen!
+    if: startsWith(github.event.comment.body, '@github-actions')
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Arrow
@@ -53,5 +53,38 @@ jobs:
           archery trigger-bot \
             --event-name ${{ github.event_name }} \
             --event-payload ${{ github.event_path }}
-
-
+  autotune:
+    name: "Fix all the things"
+    if: startsWith(github.event.comment.body, 'autotune')
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: r-lib/actions/pr-fetch@master
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+      - name: See what is different
+        run: |
+          set -ex
+          changed() {
+            git diff --name-only HEAD^.. | grep -e "$1" >/dev/null 2>&1
+          }
+          if changed '^r/.*\.R$'; then
+            echo ".R changed"
+            echo "::set-env name=R_DOCS::true"
+          fi
+      - uses: r-lib/actions/setup-r@v1
+        if: env.R_DOCS == 'true'
+      - name: Update R docs
+        if: env.R_DOCS == 'true'
+        shell: Rscript {0}
+        run: |
+          source("ci/etc/rprofile")
+          install.packages(c("remotes", "roxygen2"))
+          remotes::install_deps(r")
+          roxygen2::roxygenize("r")
+      - name: Commit results
+        run: |
+          git commit -a -m 'Autoformat/render all the things [automated commit]' --author 'GitHub Actions <actions@github.com>' || echo "No changes to commit"
+      - uses: r-lib/actions/pr-push@master
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index f1998ac4add..3d2227496ed 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -199,16 +199,7 @@ endif()
 find_program(CPPLINT_BIN NAMES cpplint cpplint.py HINTS ${BUILD_SUPPORT_DIR})
 message(STATUS "Found cpplint executable at ${CPPLINT_BIN}")
 
-add_custom_target(lint
-                  ${PYTHON_EXECUTABLE}
-                  ${BUILD_SUPPORT_DIR}/run_cpplint.py
-                  --cpplint_binary
-                  ${CPPLINT_BIN}
-                  --exclude_globs
-                  ${LINT_EXCLUSIONS_FILE}
-                  --source_dir
-                  ${CMAKE_CURRENT_SOURCE_DIR}/src
-                  ${ARROW_LINT_QUIET})
+add_custom_target(lint ${PYTHON_EXECUTABLE} ${BUILD_SUPPORT_DIR}/run_cpplint.py --cpplint_binary ${CPPLINT_BIN} --exclude_globs ${LINT_EXCLUSIONS_FILE} --source_dir ${CMAKE_CURRENT_SOURCE_DIR}/src ${ARROW_LINT_QUIET})
 
 #
 # "make format" and "make check-format" targets
diff --git a/r/R/dictionary.R b/r/R/dictionary.R
index 6273ffc2c87..6d7bfdf0b5f 100644
--- a/r/R/dictionary.R
+++ b/r/R/dictionary.R
@@ -23,10 +23,6 @@
 #' @format NULL
 #' @docType class
 #'
-#' @section Methods:
-#'
-#' TODO
-#'
 #' @rdname DictionaryType
 #' @name DictionaryType
 DictionaryType <- R6Class("DictionaryType",
diff --git a/r/R/message.R b/r/R/message.R
index ea3f3cb7bc4..8cb048da8b7 100644
--- a/r/R/message.R
+++ b/r/R/message.R
@@ -17,7 +17,7 @@
 
 #' @include arrow-package.R
 
-#' @title class arrow::Message
+#' @title class Message
 #'
 #' @usage NULL
 #' @format NULL
diff --git a/r/man/DictionaryType.Rd b/r/man/DictionaryType.Rd
index 8c9087f1ab6..828d4f8228b 100644
--- a/r/man/DictionaryType.Rd
+++ b/r/man/DictionaryType.Rd
@@ -7,9 +7,3 @@
 \description{
 class DictionaryType
 }
-\section{Methods}{
-
-
-TODO
-}
-
diff --git a/r/man/Message.Rd b/r/man/Message.Rd
index 84dd90a6459..91ae0586d80 100644
--- a/r/man/Message.Rd
+++ b/r/man/Message.Rd
@@ -3,9 +3,9 @@
 \docType{class}
 \name{Message}
 \alias{Message}
-\title{class arrow::Message}
+\title{class Message}
 \description{
-class arrow::Message
+class Message
 }
 \section{Methods}{
 
diff --git a/r/man/cpu_count.Rd b/r/man/cpu_count.Rd
index 5764da6db6a..f2abfc197ac 100644
--- a/r/man/cpu_count.Rd
+++ b/r/man/cpu_count.Rd
@@ -2,10 +2,16 @@
 % Please edit documentation in R/config.R
 \name{cpu_count}
 \alias{cpu_count}
-\title{Return number of threads used by the global CPU thread pool in libarrow}
+\alias{set_cpu_count}
+\title{Manage the global CPU thread pool in libarrow}
 \usage{
 cpu_count()
+
+set_cpu_count(num_threads)
+}
+\arguments{
+\item{num_threads}{integer: New number of threads for thread pool}
 }
 \description{
-Return number of threads used by the global CPU thread pool in libarrow
+Manage the global CPU thread pool in libarrow
 }
diff --git a/r/man/set_cpu_count.Rd b/r/man/set_cpu_count.Rd
deleted file mode 100644
index dc36e9140d2..00000000000
--- a/r/man/set_cpu_count.Rd
+++ /dev/null
@@ -1,14 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/config.R
-\name{set_cpu_count}
-\alias{set_cpu_count}
-\title{Set number of threads used by the global CPU thread pool in libarrow}
-\usage{
-set_cpu_count(num_threads)
-}
-\arguments{
-\item{num_threads}{integer: New number of threads for thread pool}
-}
-\description{
-Set number of threads used by the global CPU thread pool in libarrow
-}