diff --git a/packages/core/src/commands/command.ts b/packages/core/src/commands/command.ts
new file mode 100644
index 00000000..7f129d42
--- /dev/null
+++ b/packages/core/src/commands/command.ts
@@ -0,0 +1,5 @@
+import { Command } from '../types'
+
+export default (fn: (props: Parameters<Command>[0]) => boolean): Command => props => {
+  return fn(props)
+}
diff --git a/packages/core/src/extensions/commands.ts b/packages/core/src/extensions/commands.ts
index 3b82b620..ae0feba2 100644
--- a/packages/core/src/extensions/commands.ts
+++ b/packages/core/src/extensions/commands.ts
@@ -1,6 +1,7 @@
 import { Extension } from '../Extension'
 import blur from '../commands/blur'
 import clearContent from '../commands/clearContent'
+import command from '../commands/command'
 import clearNodes from '../commands/clearNodes'
 import deleteSelection from '../commands/deleteSelection'
 import extendMarkRange from '../commands/extendMarkRange'
@@ -43,6 +44,10 @@ export const Commands = Extension.create({
        * Normalize nodes to a simple paragraph.
        */
       clearNodes,
+      /**
+       * Define a command inline.
+       */
+      command,
       /**
        * Delete the selection, if there is one.
        */