diff --git a/doc/pages/changelog.asciidoc b/doc/pages/changelog.asciidoc
index 0cab1d0d..544a7d5f 100644
--- a/doc/pages/changelog.asciidoc
+++ b/doc/pages/changelog.asciidoc
@@ -3,6 +3,10 @@
 This changelog contains major and/or breaking changes to Kakoune between
 released versions.
 
+== Development version
+
+* `complete-command` (See <<commands#configuring-command-completion,`:doc commands configuring-command-completion`>> 
+
 == Kakoune 2021.11.07
 
 * Support for curly and separately colored underlines (undocumented in 2021.10.28)
diff --git a/doc/pages/commands.asciidoc b/doc/pages/commands.asciidoc
index 64060388..650cebb4 100644
--- a/doc/pages/commands.asciidoc
+++ b/doc/pages/commands.asciidoc
@@ -180,6 +180,11 @@ of the file onto the filesystem
     define a new alias named *name* in *scope*
     (See <<aliases,Using aliases>> and <<scopes#,`:doc scopes`>>)
 
+*complete-command* [<switches>] <name> <type> [<param>]::
+    *alias* compl +
+    configure how a command completion works
+    (See <<configuring-command-completion,Configuring command completion>>)
+
 *unalias* <scope> <name> [<command>]::
     remove an alias if its current value is the same as the one passed
     as an optional parameter, remove it unconditionally otherwise
@@ -473,25 +478,59 @@ New commands can be defined using the *define-command* command:
         define the documentation string for the command
 
     *-menu*:::
-        the suggestions generated by the completion options are the only
-        permitted parameters.
-
     *-file-completion*:::
-        try file completion on any parameter passed to this command
-
     *-client-completion*:::
-        try client name completion on any parameter passed to this command
-
     *-buffer-completion*:::
-        try buffer name completion on any parameter passed to this command
-
     *-command-completion*:::
-        try command completion on any parameter passed to this command
-
     *-shell-completion*:::
-        try shell command completion on any parameter passed to this command
-
     *-shell-script-completion*:::
+    *-shell-script-candidates*:::
+        old-style command completion specification, function as-if
+        the switch and its eventual parameter was passed to the
+        *complete-command* command
+        (See <<configuring-command-completion,Configuring command completion>>)
+
+        The use of those switches is discouraged in favor of the
+        *complete-command* command.
+
+Using shell expansion allows defining complex commands or accessing
+Kakoune's state:
+
+---------------------------------------------------------------------
+# create a directory for current buffer if it does not exist
+define-command mkdir %{ nop %sh{ mkdir -p $(dirname $kak_buffile) } }
+---------------------------------------------------------------------
+
+== Configuring command completion
+
+Command completion can be configured with the *complete-command* command:
+
+*complete-command* [<switches>] <command_name> <completion_type> [<parameter>]::
+    *switches* can be:
+
+    *-menu*:::
+        the suggestions generated by the completion options are the only
+        permitted parameters. Kakoune will autoselect the best completion
+        candidate on command validation.
+
+    *completion_type* can be:
+
+    *file-completion*:::
+        try file completion on any parameter passed to the command
+
+    *client-completion*:::
+        try client name completion on any parameter passed to the command
+
+    *buffer-completion*:::
+        try buffer name completion on any parameter passed to the command
+
+    *command-completion*:::
+        try command completion on any parameter passed to the command
+
+    *shell-completion*:::
+        try shell command completion on any parameter passed to the command
+
+    *shell-script-completion*:::
         following string is a shell command which takes parameters as
         positional params and outputs one completion candidate per line.
         The provided shell command will run after each keypress.
@@ -507,14 +546,14 @@ New commands can be defined using the *define-command* command:
             Position of the cursor inside the token being completed, in bytes
             from token start.
 
-    *-shell-script-candidates*:::
-        following string is a shell command which takes parameters as
+    *shell-script-candidates*:::
+        following string is a shell script which takes parameters as
         positional params and outputs one completion candidate per line.
-        The provided shell command will run once at the beginning of each
+        The provided shell script will run once at the beginning of each
         completion session, candidates are cached and then used by kakoune
         internal fuzzy engine.
 
-        During the execution of the shell command, the following env vars are
+        During the execution of the shell script, the following env vars are
         available:
 
         *$kak_token_to_complete*::::
@@ -522,14 +561,6 @@ New commands can be defined using the *define-command* command:
             Note that unlike the Unix `argv` tradition,
             0 is the first argument, not the command name itself.
 
-Using shell expansion allows defining complex commands or accessing
-Kakoune's state:
-
----------------------------------------------------------------------
-# create a directory for current buffer if it does not exist
-define-command mkdir %{ nop %sh{ mkdir -p $(dirname $kak_buffile) } }
----------------------------------------------------------------------
-
 == Aliases
 
 With `:alias`, commands can be given additional names.
diff --git a/rc/filetype/diff.kak b/rc/filetype/diff.kak
index b4c550a6..bb9e21d6 100644
--- a/rc/filetype/diff.kak
+++ b/rc/filetype/diff.kak
@@ -19,14 +19,14 @@ add-highlighter shared/diff/ regex "^\+[^\n]*\n" 0:green,default
 add-highlighter shared/diff/ regex "^-[^\n]*\n" 0:red,default
 add-highlighter shared/diff/ regex "^@@[^\n]*@@" 0:cyan,default
 
-define-command diff-jump \
-    -docstring %{diff-jump [<switches>] [<directory>]: edit the diff's source file at the cursor position.
-Paths are resolved relative to <directory>, or the current working directory if unspecified.
+define-command diff-jump -params .. -docstring %{
+        diff-jump [<switches>] [<directory>]: edit the diff's source file at the cursor position.
+        Paths are resolved relative to <directory>, or the current working directory if unspecified.
 
-Switches:
-    -       jump to the old file instead of the new file
-    -<num> strip <num> leading directory components, like -p<num> in patch(1). Defaults to 1 if there is a 'diff' line (as printed by 'diff -r'), or 0 otherwise.} \
-    -params .. -file-completion %{
+        Switches:
+            -       jump to the old file instead of the new file
+            -<num> strip <num> leading directory components, like -p<num> in patch(1). Defaults to 1 if there is a 'diff' line (as printed by 'diff -r'), or 0 otherwise.
+    } %{
     evaluate-commands -draft -save-regs c %{
         # Save the column because we will move the cursor.
         set-register c %val{cursor_column}
@@ -146,6 +146,7 @@ Switches:
         }
     }
 }
+complete-command diff-jump file
 
 §
 
diff --git a/rc/filetype/kakrc.kak b/rc/filetype/kakrc.kak
index 00f3c4be..ccb84ec4 100644
--- a/rc/filetype/kakrc.kak
+++ b/rc/filetype/kakrc.kak
@@ -56,7 +56,7 @@ add-highlighter shared/kakrc/shell8 region -recurse '<'  '(^|\h)\K-shell-script-
 evaluate-commands %sh{
     # Grammar
     keywords="add-highlighter alias arrange-buffers buffer buffer-next buffer-previous catch
-              change-directory colorscheme debug declare-option declare-user-mode define-command
+              change-directory colorscheme debug declare-option declare-user-mode define-command complete-command
               delete-buffer delete-buffer! echo edit edit! enter-user-mode evaluate-commands execute-keys
               fail hook info kill kill! map menu nop on-key prompt provide-module quit quit!
               remove-highlighter remove-hooks rename-buffer rename-client rename-session require-module
diff --git a/rc/tools/grep.kak b/rc/tools/grep.kak
index f68d20e8..c7c27a35 100644
--- a/rc/tools/grep.kak
+++ b/rc/tools/grep.kak
@@ -4,7 +4,7 @@ declare-option -docstring "name of the client in which utilities display informa
     str toolsclient
 declare-option -hidden int grep_current_line 0
 
-define-command -params .. -file-completion -docstring %{
+define-command -params .. -docstring %{
     grep [<arguments>]: grep utility wrapper
     All optional arguments are forwarded to the grep utility
 } grep %{ evaluate-commands %sh{
@@ -23,6 +23,7 @@ define-command -params .. -file-completion -docstring %{
                hook -always -once buffer BufCloseFifo .* %{ nop %sh{ rm -r $(dirname ${output}) } }
            }"
 }}
+complete-command grep file 
 
 hook -group grep-highlight global WinSetOption filetype=grep %{
     add-highlighter window/grep group
diff --git a/rc/windowing/iterm.kak b/rc/windowing/iterm.kak
index f3d72d3e..d99a975c 100644
--- a/rc/windowing/iterm.kak
+++ b/rc/windowing/iterm.kak
@@ -36,22 +36,25 @@ define-command -hidden -params 2.. iterm-terminal-split-impl %{
     }
 }
 
-define-command iterm-terminal-vertical -params 1.. -shell-completion -docstring '
+define-command iterm-terminal-vertical -params 1.. -docstring '
 iterm-terminal-vertical <program> [<arguments>]: create a new terminal as an iterm pane
 The current pane is split into two, left and right
 The program passed as argument will be executed in the new terminal'\
 %{
     iterm-terminal-split-impl 'vertically' %arg{@}
 }
-define-command iterm-terminal-horizontal -params 1.. -shell-completion -docstring '
+complete-command iterm-terminal-vertical shell
+
+define-command iterm-terminal-horizontal -params 1.. -docstring '
 iterm-terminal-horizontal <program> [<arguments>]: create a new terminal as an iterm pane
 The current pane is split into two, top and bottom
 The program passed as argument will be executed in the new terminal'\
 %{
     iterm-terminal-split-impl 'horizontally' %arg{@}
 }
+complete-command iterm-terminal-horizontal shell
 
-define-command iterm-terminal-tab -params 1.. -shell-completion -docstring '
+define-command iterm-terminal-tab -params 1.. -docstring '
 iterm-terminal-tab <program> [<arguments>]: create a new terminal as an iterm tab
 The program passed as argument will be executed in the new terminal'\
 %{
@@ -76,8 +79,9 @@ The program passed as argument will be executed in the new terminal'\
         -e "end tell" >/dev/null
     }
 }
+complete-command iterm-terminal-tab shell
 
-define-command iterm-terminal-window -params 1.. -shell-completion -docstring '
+define-command iterm-terminal-window -params 1.. -docstring '
 iterm-terminal-window <program> [<arguments>]: create a new terminal as an iterm window
 The program passed as argument will be executed in the new terminal'\
 %{
@@ -100,8 +104,9 @@ The program passed as argument will be executed in the new terminal'\
         -e "end tell" >/dev/null
     }
 }
+complete-command iterm-terminal-window shell
 
-define-command iterm-focus -params ..1 -client-completion -docstring '
+define-command iterm-focus -params ..1 -docstring '
 iterm-focus [<client>]: focus the given client
 If no client is passed then the current one is used' \
 %{
@@ -131,6 +136,7 @@ If no client is passed then the current one is used' \
         fi
     }
 }
+complete-command iterm-focus client
 
 alias global focus iterm-focus
 alias global terminal iterm-terminal-vertical
diff --git a/rc/windowing/kitty.kak b/rc/windowing/kitty.kak
index 5790a7c4..1e4880dc 100644
--- a/rc/windowing/kitty.kak
+++ b/rc/windowing/kitty.kak
@@ -10,7 +10,7 @@ evaluate-commands %sh{
 
 declare-option -docstring %{window type that kitty creates on new and repl calls (window|os-window)} str kitty_window_type window
 
-define-command kitty-terminal -params 1.. -shell-completion -docstring '
+define-command kitty-terminal -params 1.. -docstring '
 kitty-terminal <program> [<arguments>]: create a new terminal as a kitty window
 The program passed as argument will be executed in the new terminal' \
 %{
@@ -28,8 +28,9 @@ The program passed as argument will be executed in the new terminal' \
         kitty @ $listen launch --no-response --type="$kak_opt_kitty_window_type" --cwd="$PWD" $match "$@"
     }
 }
+complete-command kitty-terminal shell
 
-define-command kitty-terminal-tab -params 1.. -shell-completion -docstring '
+define-command kitty-terminal-tab -params 1.. -docstring '
 kitty-terminal-tab <program> [<arguments>]: create a new terminal as kitty tab
 The program passed as argument will be executed in the new terminal' \
 %{
@@ -47,8 +48,9 @@ The program passed as argument will be executed in the new terminal' \
         kitty @ $listen launch --no-response --type=tab --cwd="$PWD" $match "$@"
     }
 }
+complete-command kitty-terminal-tab shell
 
-define-command kitty-focus -params ..1 -client-completion -docstring '
+define-command kitty-focus -params ..1 -docstring '
 kitty-focus [<client>]: focus the given client
 If no client is passed then the current one is used' \
 %{
@@ -70,6 +72,7 @@ If no client is passed then the current one is used' \
         fi
     }
 }
+complete-command kitty-focus client
 
 alias global terminal kitty-terminal
 alias global terminal-tab kitty-terminal-tab
diff --git a/rc/windowing/new-client.kak b/rc/windowing/new-client.kak
index ee48a509..e017344e 100644
--- a/rc/windowing/new-client.kak
+++ b/rc/windowing/new-client.kak
@@ -1,4 +1,4 @@
-define-command new -params .. -command-completion -docstring '
+define-command new -params .. -docstring '
 new [<commands>]: create a new Kakoune client
 The ''terminal'' alias is being used to determine the user''s preferred terminal emulator
 The optional arguments are passed as commands to the new client' \
@@ -6,3 +6,4 @@ The optional arguments are passed as commands to the new client' \
     terminal kak -c %val{session} -e "%arg{@}"
 }
 
+complete-command new command
diff --git a/rc/windowing/repl/dtach.kak b/rc/windowing/repl/dtach.kak
index b99e4724..02d11ecb 100644
--- a/rc/windowing/repl/dtach.kak
+++ b/rc/windowing/repl/dtach.kak
@@ -12,7 +12,6 @@ define-command -docstring %{
     All optional parameters are forwarded to the new terminal window
 } \
     -params .. \
-    -shell-completion \
     dtach-repl %{ terminal sh -c %{
         file="$(mktemp -u -t kak_dtach_repl.XXXXX)"
         trap 'rm -f "${file}"' EXIT
@@ -22,6 +21,7 @@ define-command -docstring %{
         dtach -c "${file}" -E sh -c "${@:-$SHELL}" || "${@:-$SHELL}"
     } -- %val{client} %val{session} %arg{@}
 }
+complete-command dtach-repl shell
 
 define-command dtach-send-text -params 0..1 -docstring %{
         dtach-send-text [text]: Send text to the REPL.
diff --git a/rc/windowing/repl/kitty.kak b/rc/windowing/repl/kitty.kak
index 2b7bb2a0..28ca1b89 100644
--- a/rc/windowing/repl/kitty.kak
+++ b/rc/windowing/repl/kitty.kak
@@ -4,7 +4,7 @@ hook global ModuleLoaded kitty %{
 
 provide-module kitty-repl %{
 
-define-command -params .. -shell-completion \
+define-command -params .. \
     -docstring %{
         kitty-repl [<arguments>]: Create a new window for repl interaction.
 
@@ -31,6 +31,7 @@ define-command -params .. -shell-completion \
         kitty @ $listen launch --no-response --keep-focus --type="$kak_opt_kitty_window_type" --title=kak_repl_window --cwd="$PWD" $match $cmd
     }
 }
+complete-command kitty-repl shell
 
 define-command -hidden -params 0..1 \
     -docstring %{
diff --git a/rc/windowing/repl/tmux.kak b/rc/windowing/repl/tmux.kak
index beee3e57..037799a5 100644
--- a/rc/windowing/repl/tmux.kak
+++ b/rc/windowing/repl/tmux.kak
@@ -23,17 +23,20 @@ define-command -hidden -params 1.. tmux-repl-impl %{
     }
 }
 
-define-command tmux-repl-vertical -params 0.. -command-completion -docstring "Create a new vertical pane for repl interaction" %{
+define-command tmux-repl-vertical -params 0.. -docstring "Create a new vertical pane for repl interaction" %{
     tmux-repl-impl 'split-window -v' %arg{@}
 }
+complete-command tmux-repl-vertical command
 
-define-command tmux-repl-horizontal -params 0.. -command-completion -docstring "Create a new horizontal pane for repl interaction" %{
+define-command tmux-repl-horizontal -params 0.. -docstring "Create a new horizontal pane for repl interaction" %{
     tmux-repl-impl 'split-window -h' %arg{@}
 }
+complete-command tmux-repl-horizontal command
 
-define-command tmux-repl-window -params 0.. -command-completion -docstring "Create a new window for repl interaction" %{
+define-command tmux-repl-window -params 0.. -docstring "Create a new window for repl interaction" %{
     tmux-repl-impl 'new-window' %arg{@}
 }
+complete-command tmux-repl-window command
 
 define-command -params 0..1 tmux-repl-set-pane -docstring %{
         tmux-repl-set-pane [pane number]: Set an existing tmux pane for repl interaction
diff --git a/rc/windowing/repl/x11.kak b/rc/windowing/repl/x11.kak
index 6d9b5c5b..0c37e994 100644
--- a/rc/windowing/repl/x11.kak
+++ b/rc/windowing/repl/x11.kak
@@ -11,7 +11,6 @@ define-command -docstring %{
     All optional parameters are forwarded to the new window
 } \
     -params .. \
-    -shell-completion \
     x11-repl %{ x11-terminal sh -c %{
         winid="${WINDOWID:-$(xdotool search --pid ${PPID} | tail -1)}"
         printf "evaluate-commands -try-client $1 \
@@ -20,6 +19,7 @@ define-command -docstring %{
         [ "$1" ] && "$@" || "$SHELL"
     } -- %val{client} %val{session} %arg{@}
 }
+complete-command x11-repl shell
 
 define-command x11-send-text -params 0..1 -docstring %{
         x11-send-text [text]: Send text to the REPL window.
diff --git a/rc/windowing/screen.kak b/rc/windowing/screen.kak
index 02c63a83..8e4b6ee5 100644
--- a/rc/windowing/screen.kak
+++ b/rc/windowing/screen.kak
@@ -28,21 +28,25 @@ define-command screen-terminal-impl -hidden -params 3.. %{
     }
 }
 
-define-command screen-terminal-vertical -params 1.. -shell-completion -docstring '
+define-command screen-terminal-vertical -params 1.. -docstring '
 screen-terminal-vertical <program> [<arguments>] [<arguments>]: create a new terminal as a screen pane
 The current pane is split into two, left and right
 The program passed as argument will be executed in the new terminal' \
 %{
     screen-terminal-impl 'split -v' 'focus right' %arg{@}
 }
-define-command screen-terminal-horizontal -params 1.. -shell-completion -docstring '
+complete-command screen-terminal-vertical shell
+
+define-command screen-terminal-horizontal -params 1.. -docstring '
 screen-terminal-horizontal <program> [<arguments>]: create a new terminal as a screen pane
 The current pane is split into two, top and bottom
 The program passed as argument will be executed in the new terminal' \
 %{
     screen-terminal-impl 'split -h' 'focus down' %arg{@}
 }
-define-command screen-terminal-window -params 1.. -shell-completion -docstring '
+complete-command screen-terminal-horizontal shell
+
+define-command screen-terminal-window -params 1.. -docstring '
 screen-terminal-window <program> [<arguments>]: create a new terminal as a screen window
 The program passed as argument will be executed in the new terminal' \
 %{
@@ -51,8 +55,9 @@ The program passed as argument will be executed in the new terminal' \
         screen -X screen "$@" < "/dev/$tty"
     }
 }
+complete-command screen-terminal-window shell
 
-define-command screen-focus -params ..1 -client-completion -docstring '
+define-command screen-focus -params ..1 -docstring '
 screen-focus [<client>]: focus the given client
 If no client is passed then the current one is used' \
 %{
@@ -67,6 +72,7 @@ If no client is passed then the current one is used' \
         fi
     }
 }
+complete-command screen-focus client 
 
 alias global focus screen-focus
 alias global terminal screen-terminal-vertical
diff --git a/rc/windowing/tmux.kak b/rc/windowing/tmux.kak
index a57bc7c2..fe656cc2 100644
--- a/rc/windowing/tmux.kak
+++ b/rc/windowing/tmux.kak
@@ -30,28 +30,33 @@ define-command -hidden -params 2.. tmux-terminal-impl %{
     }
 }
 
-define-command tmux-terminal-vertical -params 1.. -shell-completion -docstring '
+define-command tmux-terminal-vertical -params 1.. -docstring '
 tmux-terminal-vertical <program> [<arguments>]: create a new terminal as a tmux pane
 The current pane is split into two, top and bottom
 The program passed as argument will be executed in the new terminal' \
 %{
     tmux-terminal-impl 'split-window -v' %arg{@}
 }
-define-command tmux-terminal-horizontal -params 1.. -shell-completion -docstring '
+complete-command tmux-terminal-vertical shell
+
+define-command tmux-terminal-horizontal -params 1.. -docstring '
 tmux-terminal-horizontal <program> [<arguments>]: create a new terminal as a tmux pane
 The current pane is split into two, left and right
 The program passed as argument will be executed in the new terminal' \
 %{
     tmux-terminal-impl 'split-window -h' %arg{@}
 }
-define-command tmux-terminal-window -params 1.. -shell-completion -docstring '
+complete-command tmux-terminal-horizontal shell
+
+define-command tmux-terminal-window -params 1.. -docstring '
 tmux-terminal-window <program> [<arguments>] [<arguments>]: create a new terminal as a tmux window
 The program passed as argument will be executed in the new terminal' \
 %{
     tmux-terminal-impl 'new-window' %arg{@}
 }
+complete-command tmux-terminal-window shell
 
-define-command tmux-focus -params ..1 -client-completion -docstring '
+define-command tmux-focus -params ..1 -docstring '
 tmux-focus [<client>]: focus the given client
 If no client is passed then the current one is used' \
 %{
@@ -66,6 +71,7 @@ If no client is passed then the current one is used' \
         fi
     }
 }
+complete-command tmux-focus client
 
 ## The default behaviour for the `new` command is to open an horizontal pane in a tmux session
 alias global focus tmux-focus
diff --git a/rc/windowing/wayland.kak b/rc/windowing/wayland.kak
index 04c7ebdc..dd3632d9 100644
--- a/rc/windowing/wayland.kak
+++ b/rc/windowing/wayland.kak
@@ -28,7 +28,7 @@ A shell command is appended to the one set in this option at runtime} \
     done
 }
 
-define-command wayland-terminal -params 1.. -shell-completion -docstring '
+define-command wayland-terminal -params 1.. -docstring '
 wayland-terminal <program> [<arguments>]: create a new terminal as a Wayland window
 The program passed as argument will be executed in the new terminal' \
 %{
@@ -43,13 +43,15 @@ The program passed as argument will be executed in the new terminal' \
         }
     }
 }
+complete-command wayland-terminal shell
 
-define-command wayland-focus -params ..1 -client-completion -docstring '
+define-command wayland-focus -params ..1 -docstring '
 wayland-focus [<kakoune_client>]: focus a given client''s window
 If no client is passed, then the current client is used' \
 %{
     fail There is no way to focus another window on Wayland
 }
+complete-command wayland-focus client
 
 alias global focus wayland-focus
 alias global terminal wayland-terminal
diff --git a/rc/windowing/x11.kak b/rc/windowing/x11.kak
index 6b2d13df..4c39f7ba 100644
--- a/rc/windowing/x11.kak
+++ b/rc/windowing/x11.kak
@@ -33,7 +33,7 @@ A shell command is appended to the one set in this option at runtime} \
     done
 }
 
-define-command x11-terminal -params 1.. -shell-completion -docstring '
+define-command x11-terminal -params 1.. -docstring '
 x11-terminal <program> [<arguments>]: create a new terminal as an X11 window
 The program passed as argument will be executed in the new terminal' \
 %{
@@ -48,8 +48,9 @@ The program passed as argument will be executed in the new terminal' \
         }
     }
 }
+complete-command x11-terminal shell 
 
-define-command x11-focus -params ..1 -client-completion -docstring '
+define-command x11-focus -params ..1 -docstring '
 x11-focus [<kakoune_client>]: focus a given client''s window
 If no client is passed, then the current client is used' \
 %{
@@ -62,6 +63,7 @@ If no client is passed, then the current client is used' \
         fi
     }
 }
+complete-command x11-focus client 
 
 alias global focus x11-focus
 alias global terminal x11-terminal
diff --git a/src/command_manager.cc b/src/command_manager.cc
index 5663b1e3..0f3cb749 100644
--- a/src/command_manager.cc
+++ b/src/command_manager.cc
@@ -41,6 +41,15 @@ void CommandManager::register_command(String command_name,
                                  std::move(completer) };
 }
 
+void CommandManager::set_command_completer(StringView command_name, CommandCompleter completer)
+{
+    auto it = m_commands.find(command_name);
+    if (it == m_commands.end())
+        throw runtime_error(format("no such command '{}'", command_name));
+
+    it->value.completer = std::move(completer);
+}
+
 bool CommandManager::module_defined(StringView module_name) const
 {
     return m_modules.find(module_name) != m_modules.end();
diff --git a/src/command_manager.hh b/src/command_manager.hh
index 6489e044..d41c1dcf 100644
--- a/src/command_manager.hh
+++ b/src/command_manager.hh
@@ -112,6 +112,8 @@ public:
                           CommandHelper helper = CommandHelper(),
                           CommandCompleter completer = CommandCompleter());
 
+    void set_command_completer(StringView command_name, CommandCompleter completer);
+
     Completions complete_command_name(const Context& context, StringView query) const;
 
     void clear_last_complete_command() { m_last_complete_command = String{}; }
diff --git a/src/commands.cc b/src/commands.cc
index e66c043e..2b419e76 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -1159,6 +1159,82 @@ Vector<String> params_to_shell(const ParametersParser& parser)
     return vars;
 }
 
+CommandCompleter make_command_completer(StringView type, StringView param, Completions::Flags completions_flags)
+{
+    if (type == "file")
+    {
+        return [=](const Context& context, CompletionFlags flags,
+                   CommandParameters params,
+                   size_t token_to_complete, ByteCount pos_in_token) {
+             const String& prefix = params[token_to_complete];
+             const auto& ignored_files = context.options()["ignored_files"].get<Regex>();
+             return Completions{0_byte, pos_in_token,
+                                complete_filename(prefix, ignored_files,
+                                                  pos_in_token, FilenameFlags::Expand),
+                                completions_flags};
+        };
+    }
+    else if (type == "client")
+    {
+        return [=](const Context& context, CompletionFlags flags,
+                   CommandParameters params,
+                   size_t token_to_complete, ByteCount pos_in_token)
+        {
+             const String& prefix = params[token_to_complete];
+             auto& cm = ClientManager::instance();
+             return Completions{0_byte, pos_in_token,
+                                cm.complete_client_name(prefix, pos_in_token),
+                                completions_flags};
+        };
+    }
+    else if (type == "buffer")
+    {
+        return [=](const Context& context, CompletionFlags flags,
+                   CommandParameters params,
+                   size_t token_to_complete, ByteCount pos_in_token)
+        {
+             return add_flags(complete_buffer_name<false>, completions_flags)(
+                 context, flags, params[token_to_complete], pos_in_token);
+        };
+    }
+    else if (type == "shell-script")
+    {
+        if (param.empty())
+            throw runtime_error("shell-script requires a shell script parameter");
+
+        return ShellScriptCompleter{param.str(), completions_flags};
+    }
+    else if (type == "shell-script-candidates")
+    {
+        if (param.empty())
+            throw runtime_error("shell-script-candidates requires a shell script parameter");
+
+        return ShellCandidatesCompleter{param.str(), completions_flags};
+    }
+    else if (type == "command")
+    {
+        return [](const Context& context, CompletionFlags flags,
+                  CommandParameters params,
+                  size_t token_to_complete, ByteCount pos_in_token)
+        {
+            return CommandManager::instance().complete(
+                context, flags, params, token_to_complete, pos_in_token);
+        };
+    }
+    else if (type == "shell")
+    {
+        return [=](const Context& context, CompletionFlags flags,
+                   CommandParameters params,
+                   size_t token_to_complete, ByteCount pos_in_token)
+        {
+            return add_flags(shell_complete, completions_flags)(
+                context, flags, params[token_to_complete], pos_in_token);
+        };
+    }
+    else
+        throw runtime_error(format("invalid command completion type '{}'", type));
+}
+
 void define_command(const ParametersParser& parser, Context& context, const ShellContext&)
 {
     const String& cmd_name = parser[0];
@@ -1211,75 +1287,22 @@ void define_command(const ParametersParser& parser, Context& context, const Shel
     }
 
     CommandCompleter completer;
-    if (parser.get_switch("file-completion"))
+    for (StringView completion_switch : {"file-completion", "client-completion", "buffer-completion",
+                                         "shell-script-completion", "shell-script-candidates",
+                                         "command-completion", "shell-completion"})
     {
-        completer = [=](const Context& context, CompletionFlags flags,
-                       CommandParameters params,
-                       size_t token_to_complete, ByteCount pos_in_token)
+        if (auto param = parser.get_switch(completion_switch))
         {
-             const String& prefix = params[token_to_complete];
-             const auto& ignored_files = context.options()["ignored_files"].get<Regex>();
-             return Completions{0_byte, pos_in_token,
-                                complete_filename(prefix, ignored_files,
-                                                  pos_in_token, FilenameFlags::Expand),
-                                completions_flags};
-        };
+            constexpr StringView suffix = "-completion";
+            if (completion_switch.ends_with(suffix))
+                completion_switch = completion_switch.substr(0, completion_switch.length() - suffix.length());
+            completer = make_command_completer(completion_switch, *param, completions_flags);
+            break;
+        }
     }
-    else if (parser.get_switch("client-completion"))
-    {
-        completer = [=](const Context& context, CompletionFlags flags,
-                       CommandParameters params,
-                       size_t token_to_complete, ByteCount pos_in_token)
-        {
-             const String& prefix = params[token_to_complete];
-             auto& cm = ClientManager::instance();
-             return Completions{0_byte, pos_in_token,
-                                cm.complete_client_name(prefix, pos_in_token),
-                                completions_flags};
-        };
-    }
-    else if (parser.get_switch("buffer-completion"))
-    {
-        completer = [=](const Context& context, CompletionFlags flags,
-                       CommandParameters params,
-                       size_t token_to_complete, ByteCount pos_in_token)
-        {
-             return add_flags(complete_buffer_name<false>, completions_flags)(
-                 context, flags, params[token_to_complete], pos_in_token);
-        };
-    }
-    else if (auto shell_script = parser.get_switch("shell-script-completion"))
-    {
-        completer = ShellScriptCompleter{shell_script->str(), completions_flags};
-    }
-    else if (auto shell_script = parser.get_switch("shell-script-candidates"))
-    {
-        completer = ShellCandidatesCompleter{shell_script->str(), completions_flags};
-    }
-    else if (parser.get_switch("command-completion"))
-    {
-        completer = [](const Context& context, CompletionFlags flags,
-                       CommandParameters params,
-                       size_t token_to_complete, ByteCount pos_in_token)
-        {
-            return CommandManager::instance().complete(
-                context, flags, params, token_to_complete, pos_in_token);
-        };
-    }
-    else if (parser.get_switch("shell-completion"))
-    {
-        completer = [=](const Context& context, CompletionFlags flags,
-                        CommandParameters params,
-                        size_t token_to_complete, ByteCount pos_in_token)
-        {
-            return add_flags(shell_complete, completions_flags)(
-                context, flags, params[token_to_complete], pos_in_token);
-        };
-    }
-
     auto docstring = trim_indent(parser.get_switch("docstring").value_or(StringView{}));
 
-    cm.register_command(cmd_name, cmd, docstring, desc, flags, CommandHelper{}, completer);
+    cm.register_command(cmd_name, cmd, docstring, desc, flags, CommandHelper{}, std::move(completer));
 }
 
 const CommandDesc define_command_cmd = {
@@ -1354,6 +1377,25 @@ const CommandDesc unalias_cmd = {
     }
 };
 
+const CommandDesc complete_command_cmd = {
+    "complete-command",
+    "compl",
+    "complete-command [<switches>] <name> <type> [<param>]\n"
+    "define command completion",
+    ParameterDesc{
+        { { "menu",                     { false, "treat completions as the only valid inputs" } }, },
+        ParameterDesc::Flags::None, 2, 3},
+    CommandFlags::None,
+    CommandHelper{},
+    make_completer(complete_command_name),
+    [](const ParametersParser& parser, Context& context, const ShellContext&)
+    {
+        const Completions::Flags flags = parser.get_switch("menu") ? Completions::Flags::Menu : Completions::Flags::None;
+        CommandCompleter completer = make_command_completer(parser[1], parser.positional_count() >= 3 ? parser[2] : StringView{}, flags);
+        CommandManager::instance().set_command_completer(parser[0], std::move(completer));
+    }
+};
+
 const CommandDesc echo_cmd = {
     "echo",
     nullptr,
@@ -2719,6 +2761,7 @@ void register_commands()
     register_command(remove_hook_cmd);
     register_command(trigger_user_hook_cmd);
     register_command(define_command_cmd);
+    register_command(complete_command_cmd);
     register_command(alias_cmd);
     register_command(unalias_cmd);
     register_command(echo_cmd);
diff --git a/src/main.cc b/src/main.cc
index 98e33d83..eb240288 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -46,6 +46,7 @@ struct {
 } constexpr version_notes[] = { {
         0,
         "» pipe commands do not append final end-of-lines anymore\n"
+        "» {+u}complete-command{} to configure command completion\n"
     }, {
         20211107,
         "» colored and curly underlines support (undocumented in 20210828)\n"
diff --git a/src/string.hh b/src/string.hh
index d14929f4..c3e7401f 100644
--- a/src/string.hh
+++ b/src/string.hh
@@ -67,6 +67,9 @@ public:
     [[gnu::always_inline]]
     bool empty() const { return type().length() == 0_byte; }
 
+    bool starts_with(StringView str) const;
+    bool ends_with(StringView str) const;
+
     ByteCount byte_count_to(CharCount count) const
     { return utf8::advance(begin(), end(), count) - begin(); }
 
@@ -306,6 +309,22 @@ inline StringView StringOps<Type, CharType>::substr(ColumnCount from, ColumnCoun
     return StringView{ beg, utf8::advance(beg, end(), length) };
 }
 
+template<typename Type, typename CharType>
+inline bool StringOps<Type, CharType>::starts_with(StringView str) const
+{
+    if (type().length() < str.length())
+        return false;
+    return substr(0, str.length()) == str;
+}
+
+template<typename Type, typename CharType>
+inline bool StringOps<Type, CharType>::ends_with(StringView str) const
+{
+    if (type().length() < str.length())
+        return false;
+    return substr(type().length() - str.length()) == str;
+}
+
 inline String& operator+=(String& lhs, StringView rhs)
 {
     lhs.append(rhs.data(), rhs.length());
diff --git a/src/string_utils.cc b/src/string_utils.cc
index a1c1c38d..37ca6716 100644
--- a/src/string_utils.cc
+++ b/src/string_utils.cc
@@ -396,6 +396,16 @@ UnitTest test_string{[]()
 {
     kak_assert(String("youpi ") + "matin" == "youpi matin");
 
+    kak_assert(StringView{"youpi"}.starts_with(""));
+    kak_assert(StringView{"youpi"}.starts_with("you"));
+    kak_assert(StringView{"youpi"}.starts_with("youpi"));
+    kak_assert(not StringView{"youpi"}.starts_with("youpi!"));
+
+    kak_assert(StringView{"youpi"}.ends_with(""));
+    kak_assert(StringView{"youpi"}.ends_with("pi"));
+    kak_assert(StringView{"youpi"}.ends_with("youpi"));
+    kak_assert(not StringView{"youpi"}.ends_with("oup"));
+
     auto wrapped = "wrap this paragraph\n respecting whitespaces and much_too_long_words" | wrap_at(16) | gather<Vector>();
     kak_assert(wrapped.size() == 6);
     kak_assert(wrapped[0] == "wrap this");