diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
 # Changelog for sandwich
 
 ## Unreleased changes
+
+## 0.1.0.5
+
+* Add `parallelN` for limiting the number of threads in a `parallel`.
diff --git a/sandwich.cabal b/sandwich.cabal
--- a/sandwich.cabal
+++ b/sandwich.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.33.0.
+-- This file has been generated from package.yaml by hpack version 0.34.4.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 244c3e7999c4afac51c061a4e2ca5575aeb323ac3ee3c20b70f36df7a861a50d
+-- hash: aa45aa821e6aa80865e26cf2911cf666e76b4e5ce6ba1a0ef5b08a4ff626640d
 
 name:           sandwich
-version:        0.1.0.5
+version:        0.1.0.6
 synopsis:       Yet another test framework for Haskell
 description:    Please see the <https://codedownio.github.io/sandwich documentation>.
 category:       Testing
@@ -75,6 +75,7 @@
       Test.Sandwich.Interpreters.RunTree.Logging
       Test.Sandwich.Interpreters.RunTree.Util
       Test.Sandwich.Interpreters.StartTree
+      Test.Sandwich.ParallelN
       Test.Sandwich.RunTree
       Test.Sandwich.Shutdown
       Test.Sandwich.TestTimer
diff --git a/src/Test/Sandwich.hs b/src/Test/Sandwich.hs
--- a/src/Test/Sandwich.hs
+++ b/src/Test/Sandwich.hs
@@ -37,6 +37,7 @@
   , it
   , describe
   , parallel
+  , parallelN
 
   -- * Context manager nodes
   --
@@ -100,6 +101,7 @@
 import Test.Sandwich.Misc
 import Test.Sandwich.Nodes
 import Test.Sandwich.Options
+import Test.Sandwich.ParallelN
 import Test.Sandwich.RunTree
 import Test.Sandwich.Shutdown
 import Test.Sandwich.TH
diff --git a/src/Test/Sandwich/ArgParsing.hs b/src/Test/Sandwich/ArgParsing.hs
--- a/src/Test/Sandwich/ArgParsing.hs
+++ b/src/Test/Sandwich/ArgParsing.hs
@@ -65,7 +65,7 @@
 
   <*> optional (flag False True (long "list-tests" <> help "List individual test modules"))
   <*> optional (flag False True (long "print-slack-flags" <> help "Print the additional Slack flags"))
-  <*> optional (flag False True (long "print-webdriver-flags" <> help "Print the additional Slack flags"))
+  <*> optional (flag False True (long "print-webdriver-flags" <> help "Print the additional Webdriver flags"))
 
   <*> individualTestParser
 
diff --git a/src/Test/Sandwich/Contexts.hs b/src/Test/Sandwich/Contexts.hs
--- a/src/Test/Sandwich/Contexts.hs
+++ b/src/Test/Sandwich/Contexts.hs
@@ -32,3 +32,8 @@
 -- introduce them manually
 getCommandLineOptions :: (HasCommandLineOptions context a, MonadReader context m, MonadIO m) => m (CommandLineOptions a)
 getCommandLineOptions = getContext commandLineOptions
+
+-- | Get the user command line options, if configured.
+-- This just calls 'getCommandLineOptions' and pulls out the user options.
+getUserCommandLineOptions :: (HasCommandLineOptions context a, MonadReader context m, MonadIO m) => m a
+getUserCommandLineOptions = optUserOptions <$> getContext commandLineOptions
diff --git a/src/Test/Sandwich/Formatters/Print/FailureReason.hs b/src/Test/Sandwich/Formatters/Print/FailureReason.hs
--- a/src/Test/Sandwich/Formatters/Print/FailureReason.hs
+++ b/src/Test/Sandwich/Formatters/Print/FailureReason.hs
@@ -24,7 +24,7 @@
 
 printFailureReason :: FailureReason -> ReaderT (PrintFormatter, Int, Handle) IO ()
 printFailureReason (Reason _ s) = do
-  printShowBoxPrettyWithTitle "Reason: " (SEB s)
+  printShowBoxPrettyWithTitleString "Reason: " s
 printFailureReason (ChildrenFailed _ n) = do
   picn midWhite ([i|#{n} #{if n == 1 then ("child" :: String) else "children"} failed|] :: String)
 printFailureReason (ExpectedButGot _ seb1 seb2) = do
@@ -70,6 +70,9 @@
         picn midWhite title
         printPretty True x >> p "\n"
 
--- printShowBoxPretty (SEB v) = case P.reify v of
---   Nothing -> forM_ (L.lines $ show v) pin
---   Just x -> printPretty True x >> p "\n"
+printShowBoxPrettyWithTitleString :: String -> String -> ReaderT (PrintFormatter, Int, Handle) IO ()
+printShowBoxPrettyWithTitleString title s = do
+  picn midWhite title
+  withBumpIndent $ do
+    forM_ (L.lines s) pin
+  p "\n"
diff --git a/src/Test/Sandwich/Interpreters/StartTree.hs b/src/Test/Sandwich/Interpreters/StartTree.hs
--- a/src/Test/Sandwich/Interpreters/StartTree.hs
+++ b/src/Test/Sandwich/Interpreters/StartTree.hs
@@ -132,7 +132,7 @@
     let wrappedAction = do
           let failureResult e = case fromException e of
                 Just fr@(Pending {}) -> Failure fr
-                _ -> Failure $ Reason Nothing [i|around #{runTreeLabel} handler threw exception|]
+                _ -> Failure $ Reason Nothing [i|around '#{runTreeLabel}' handler threw exception|]
           flip withException (\e -> recordExceptionInStatus runTreeStatus e >> markAllChildrenWithResult runNodeChildren ctx (failureResult e)) $ do
             runNodeActionWith $ do
               results <- liftIO $ runNodesSequentially runNodeChildren ctx
@@ -140,7 +140,7 @@
               return results
 
           (liftIO $ readIORef didRunWrappedAction) >>= \case
-            Left () -> return $ Failure $ Reason Nothing [i|introduceWith '#{runTreeLabel}' handler didn't call action|]
+            Left () -> return $ Failure $ Reason Nothing [i|around '#{runTreeLabel}' handler didn't call action|]
             Right _ -> return Success
     runExampleM'' wrappedAction ctx runTreeLogs (Just [i|Exception in introduceWith '#{runTreeLabel}' handler|])
 startTree node@(RunNodeDescribe {..}) ctx' = do
diff --git a/src/Test/Sandwich/Logging.hs b/src/Test/Sandwich/Logging.hs
--- a/src/Test/Sandwich/Logging.hs
+++ b/src/Test/Sandwich/Logging.hs
@@ -65,22 +65,7 @@
   (_, _, _, p) <- liftIO $ createProcess (cp { std_out = UseHandle hWrite, std_err = UseHandle hWrite })
   return p
 
--- | Same as 'createProcessWithLogging', but using 'readCreateProcess'.
-readCreateProcessWithLogging :: (MonadIO m, MonadBaseControl IO m, MonadLogger m) => CreateProcess -> String -> m String
-readCreateProcessWithLogging cp input = do
-  (hRead, hWrite) <- liftIO createPipe
-
-  let name = case cmdspec cp of
-        ShellCommand {} -> "shell"
-        RawCommand path _ -> path
-
-  _ <- async $ forever $ do
-    line <- liftIO $ hGetLine hRead
-    debug [i|#{name}: #{line}|]
-
-  liftIO $ readCreateProcess (cp { std_out = UseHandle hWrite, std_err = UseHandle hWrite }) input
-
--- | Higher level version of 'readCreateProcessWithLogging', accepting a shell command.
+-- | Higher level version of 'createProcessWithLogging', accepting a shell command.
 callCommandWithLogging :: (MonadIO m, MonadBaseControl IO m, MonadLogger m) => String -> m ()
 callCommandWithLogging cmd = do
   (hRead, hWrite) <- liftIO createPipe
diff --git a/src/Test/Sandwich/ParallelN.hs b/src/Test/Sandwich/ParallelN.hs
new file mode 100644
--- /dev/null
+++ b/src/Test/Sandwich/ParallelN.hs
@@ -0,0 +1,34 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+-- | Wrapper around 'parallel' for limiting the threads using a semaphore.
+
+module Test.Sandwich.ParallelN (parallelN) where
+
+import Control.Concurrent.QSem
+import Control.Exception.Safe
+import Control.Monad
+import Control.Monad.IO.Class
+import Control.Monad.Trans.Control (MonadBaseControl)
+import Test.Sandwich.Types.Spec
+import Test.Sandwich.Contexts
+
+
+
+-- | Wrapped around 'parallel'. Introduces a semaphore to limit the parallelism to N threads.
+parallelN :: (
+  MonadBaseControl IO m, MonadIO m, MonadMask m
+  ) => Int -> SpecFree (LabelValue "parallelSemaphore" QSem :> context) m () -> SpecFree context m ()
+parallelN n children = introduceParallelSemaphore n $ parallel $ aroundEach "Take parallel semaphore" claimRunSlot children
+  where claimRunSlot f = do
+          s <- getContext parallelSemaphore
+          bracket_ (liftIO $ waitQSem s) (liftIO $ signalQSem s) (void f)
+
+parallelSemaphore :: Label "parallelSemaphore" QSem
+parallelSemaphore = Label
+
+introduceParallelSemaphore :: (
+  MonadIO m, MonadBaseControl IO m
+  ) => Int -> SpecFree (LabelValue "parallelSemaphore" QSem :> context) m () -> SpecFree context m ()
+introduceParallelSemaphore n = introduce "Introduce parallel semaphore" parallelSemaphore (liftIO $ newQSem n) (const $ return ())