diff --git a/src/main/java/de/prob2/jupyter/commands/BrowseCommand.java b/src/main/java/de/prob2/jupyter/commands/BrowseCommand.java
index d6b8d353cf4b894572bc360f75fb5ee08a8a39b2..a26229b4bc218b4c4e318ea510e386cdcae9f16f 100644
--- a/src/main/java/de/prob2/jupyter/commands/BrowseCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/BrowseCommand.java
@@ -82,6 +82,11 @@ public final class BrowseCommand implements Command {
 		return new DisplayData(sb.toString());
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/CheckCommand.java b/src/main/java/de/prob2/jupyter/commands/CheckCommand.java
index c8ca6851e5635fa2f9525b7df0749ef0d87a90d0..e1fba4bbe1f64ba7efc1eb06fb04d7e8a372e113 100644
--- a/src/main/java/de/prob2/jupyter/commands/CheckCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/CheckCommand.java
@@ -24,6 +24,7 @@ import io.github.spencerpark.jupyter.kernel.ReplacementOptions;
 import io.github.spencerpark.jupyter.kernel.display.DisplayData;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public final class CheckCommand implements Command {
 	private static final @NotNull Map<@NotNull String, @NotNull String> SECTION_NAME_MAP;
@@ -95,6 +96,11 @@ public final class CheckCommand implements Command {
 		}
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @NotNull ReplacementOptions complete(final @NotNull String argString, final int at) {
 		final String prefix = argString.substring(0, at);
diff --git a/src/main/java/de/prob2/jupyter/commands/Command.java b/src/main/java/de/prob2/jupyter/commands/Command.java
index fb906dc3b3561817977151c3e47d53206f1dfad5..1e9471c8be38fbbc8a0b4c98179290e2ff8d14a5 100644
--- a/src/main/java/de/prob2/jupyter/commands/Command.java
+++ b/src/main/java/de/prob2/jupyter/commands/Command.java
@@ -39,9 +39,7 @@ public interface Command {
 	
 	public abstract @Nullable DisplayData run(final @NotNull String argString);
 	
-	public default @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
-		return null;
-	}
+	public abstract @Nullable DisplayData inspect(final @NotNull String argString, final int at);
 	
 	public abstract @Nullable ReplacementOptions complete(final @NotNull String argString, final int at);
 }
diff --git a/src/main/java/de/prob2/jupyter/commands/GotoCommand.java b/src/main/java/de/prob2/jupyter/commands/GotoCommand.java
index 37f8d862a730677c216ed24d4aea9b0d098f09cc..c2478168b64954facf7741b99a18118dcfae1d9c 100644
--- a/src/main/java/de/prob2/jupyter/commands/GotoCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/GotoCommand.java
@@ -49,6 +49,11 @@ public final class GotoCommand implements Command {
 		return new DisplayData("Changed to state with index " + index);
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/GroovyCommand.java b/src/main/java/de/prob2/jupyter/commands/GroovyCommand.java
index 6eb9988fe9216c59c656ab409ce8bb81da774a15..8a0a1e46c64c7520f16d9dc1cccfef024945df52 100644
--- a/src/main/java/de/prob2/jupyter/commands/GroovyCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/GroovyCommand.java
@@ -59,6 +59,11 @@ public final class GroovyCommand implements Command {
 		return new DisplayData(Objects.toString(result));
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/HelpCommand.java b/src/main/java/de/prob2/jupyter/commands/HelpCommand.java
index bfee91299fe0a58f1344f3902c1042d58e1b3122..e32bbc8cdf2cf54d4a236d9d9c686a6b43a53ae2 100644
--- a/src/main/java/de/prob2/jupyter/commands/HelpCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/HelpCommand.java
@@ -14,6 +14,7 @@ import io.github.spencerpark.jupyter.kernel.ReplacementOptions;
 import io.github.spencerpark.jupyter.kernel.display.DisplayData;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public final class HelpCommand implements Command {
 	private final @NotNull Injector injector;
@@ -83,6 +84,11 @@ public final class HelpCommand implements Command {
 		}
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @NotNull ReplacementOptions complete(final @NotNull String argString, final int at) {
 		final String prefix = argString.substring(0, at);
diff --git a/src/main/java/de/prob2/jupyter/commands/RenderCommand.java b/src/main/java/de/prob2/jupyter/commands/RenderCommand.java
index ebb2a0e3bc2e56677745c84a7778a114dc193882..aa5b8719cab60bae16ab8e14dabb77d37fff2811 100644
--- a/src/main/java/de/prob2/jupyter/commands/RenderCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/RenderCommand.java
@@ -48,6 +48,11 @@ public final class RenderCommand implements Command {
 		return data;
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/ShowCommand.java b/src/main/java/de/prob2/jupyter/commands/ShowCommand.java
index 22daba74dfeeb838b8a733c8eaa5326a1d332033..3a3af354e7cfc1a5cda67cbaef7817a6a1df0cac 100644
--- a/src/main/java/de/prob2/jupyter/commands/ShowCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/ShowCommand.java
@@ -126,6 +126,11 @@ public final class ShowCommand implements Command {
 		return result;
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/StatsCommand.java b/src/main/java/de/prob2/jupyter/commands/StatsCommand.java
index c208bcfd885341e44559b9cf1c897a0252f1847b..a693fb9f0d67a010e7924abda3ada852311b0820 100644
--- a/src/main/java/de/prob2/jupyter/commands/StatsCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/StatsCommand.java
@@ -72,6 +72,11 @@ public final class StatsCommand implements Command {
 		return result;
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/TraceCommand.java b/src/main/java/de/prob2/jupyter/commands/TraceCommand.java
index 72ff13fe1dfd3e5a9487df6402b2813d0390b039..53dcea7a4c6bafc7637135e8bcf876245a1c5098 100644
--- a/src/main/java/de/prob2/jupyter/commands/TraceCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/TraceCommand.java
@@ -79,6 +79,11 @@ public final class TraceCommand implements Command {
 		return result;
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;
diff --git a/src/main/java/de/prob2/jupyter/commands/VersionCommand.java b/src/main/java/de/prob2/jupyter/commands/VersionCommand.java
index 4c71ae0cf2cbf1aaaadbb4739cf9d6be7ec2da70..82af3da6f727f6801925500d71745455884ec69b 100644
--- a/src/main/java/de/prob2/jupyter/commands/VersionCommand.java
+++ b/src/main/java/de/prob2/jupyter/commands/VersionCommand.java
@@ -44,6 +44,11 @@ public final class VersionCommand implements Command {
 		return new DisplayData(String.format("ProB CLI: %s\nProB 2: %s (%s)", cmd.getVersion(), Main.getVersion(), Main.getGitSha()));
 	}
 	
+	@Override
+	public @Nullable DisplayData inspect(final @NotNull String argString, final int at) {
+		return null;
+	}
+	
 	@Override
 	public @Nullable ReplacementOptions complete(final @NotNull String argString, final int at) {
 		return null;