diff --git a/changelog.md b/changelog.md
index 2c9f27a6..fb622df9 100644
--- a/changelog.md
+++ b/changelog.md
@@ -4,6 +4,7 @@ Upcoming (TBD)
 Features
 ---------
 * Allow shorter timeout lengths after pressing Esc, for vi-mode.
+* Let tab and control-space behaviors be configurable.
 
 
 1.60.0 (2026/03/05)
diff --git a/mycli/key_bindings.py b/mycli/key_bindings.py
index 86597483..d209f726 100644
--- a/mycli/key_bindings.py
+++ b/mycli/key_bindings.py
@@ -12,6 +12,7 @@
 )
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit.key_binding.key_processor import KeyPressEvent
+from prompt_toolkit.selection import SelectionType
 
 from mycli.constants import DOCS_URL
 from mycli.packages import shortcuts
@@ -124,13 +125,31 @@ def _(event: KeyPressEvent) -> None:
 
     @kb.add("tab")
     def _(event: KeyPressEvent) -> None:
-        """Force autocompletion at cursor."""
+        """Complete action at cursor."""
         _logger.debug("Detected <Tab> key.")
         b = event.app.current_buffer
+
+        behaviors = mycli.config['keys'].as_list('tab')
+
+        if 'toolkit_default' in behaviors:
+            if b.complete_state:
+                b.complete_next()
+            else:
+                b.start_completion(select_first=True)
+
         if b.complete_state:
-            b.complete_next()
-        else:
+            if 'advance' in behaviors:
+                b.complete_next()
+            elif 'cancel' in behaviors:
+                b.cancel_completion()
+            return
+
+        if 'advancing_summon' in behaviors:
             b.start_completion(select_first=True)
+        elif 'prefixing_summon' in behaviors:
+            b.start_completion(insert_common_part=True)
+        elif 'summon' in behaviors:
+            b.start_completion(select_first=False)
 
     @kb.add("escape", eager=True, filter=in_completion)
     def _(event: KeyPressEvent) -> None:
@@ -145,9 +164,9 @@ def _(event: KeyPressEvent) -> None:
     @kb.add("c-space")
     def _(event: KeyPressEvent) -> None:
         """
-        Initialize autocompletion at cursor.
+        Complete action at cursor.
 
-        If the autocompletion menu is not showing, display it with the
+        By default, if the autocompletion menu is not showing, display it with the
         appropriate completions for the context.
 
         If the menu is showing, select the next completion.
@@ -155,9 +174,26 @@ def _(event: KeyPressEvent) -> None:
         _logger.debug("Detected <C-Space> key.")
 
         b = event.app.current_buffer
+
+        behaviors = mycli.config['keys'].as_list('control_space')
+
+        if 'toolkit_default' in behaviors:
+            if b.text:
+                b.start_selection(selection_type=SelectionType.CHARACTERS)
+            return
+
         if b.complete_state:
-            b.complete_next()
-        else:
+            if 'advance' in behaviors:
+                b.complete_next()
+            elif 'cancel' in behaviors:
+                b.cancel_completion()
+            return
+
+        if 'advancing_summon' in behaviors:
+            b.start_completion(select_first=True)
+        elif 'prefixing_summon' in behaviors:
+            b.start_completion(insert_common_part=True)
+        elif 'summon' in behaviors:
             b.start_completion(select_first=False)
 
     @kb.add("c-x", "p", filter=emacs_mode)
diff --git a/mycli/myclirc b/mycli/myclirc
index 5060386d..1d741811 100644
--- a/mycli/myclirc
+++ b/mycli/myclirc
@@ -235,6 +235,19 @@ control_d = exit
 # possible values: auto, fzf, reverse_isearch
 control_r = auto
 
+# comma-separated list: toolkit_default, summon, advancing_summon, prefixing_summon, advance, cancel
+#
+# * toolkit_default - ignore other behaviors and use prompt_toolkit's default bindings
+# * summon - when completions are not visible, summon them
+# * advancing_summon - when completions are not visible, summon them _and_ advance in the list
+# * prefixing_summon - when completions are not visible, summon them _and_ insert the common prefix
+# * advance - when completions are visible, advance in the list
+# * cancel - when completions are visible, toggle the list off
+control_space = summon, advance
+
+# comma-separated list: toolkit_default, summon, advancing_summon, prefixing_summon, advance, cancel
+tab = advancing_summon, advance
+
 # How long to wait for an Escape key sequence in vi mode.
 # 0.5 seconds is the prompt_toolkit default, but vi users may find that too long.
 # Shorter values mean that "Escape" alone is recognized more quickly.
diff --git a/test/myclirc b/test/myclirc
index 64966274..734f07ef 100644
--- a/test/myclirc
+++ b/test/myclirc
@@ -233,6 +233,19 @@ control_d = exit
 # possible values: auto, fzf, reverse_isearch
 control_r = auto
 
+# comma-separated list: toolkit_default, summon, advancing_summon, prefixing_summon, advance, cancel
+#
+# * toolkit_default - ignore other behaviors and use prompt_toolkit's default bindings
+# * summon - when completions are not visible, summon them
+# * advancing_summon - when completions are not visible, summon them _and_ advance in the list
+# * prefixing_summon - when completions are not visible, summon them _and_ insert the common prefix
+# * advance - when completions are visible, advance in the list
+# * cancel - when completions are visible, toggle the list off
+control_space = summon, advance
+
+# comma-separated list: toolkit_default, summon, advancing_summon, prefixing_summon, advance, cancel
+tab = advancing_summon, advance
+
 # How long to wait for an Escape key sequence in vi mode.
 # 0.5 seconds is the prompt_toolkit default, but vi users may find that too long.
 # Shorter values mean that "Escape" alone is recognized more quickly.