diff --git a/app/controllers/commands_controller.rb b/app/controllers/commands_controller.rb
index ae5c2232e..adae98eb1 100644
--- a/app/controllers/commands_controller.rb
+++ b/app/controllers/commands_controller.rb
@@ -68,6 +68,7 @@ class CommandsController < ApplicationController
     end
 
     def respond_with_error(command)
-      render json: { error: command.errors.full_messages.join(", "), context_url: command.context.url }, status: :unprocessable_entity
+      error_message = command.error_messages.map { |msg| "- #{msg}\n" }.join
+      render json: { error: error_message, context_url: command.context.url }, status: :unprocessable_entity
     end
 end
diff --git a/app/javascript/controllers/terminal_controller.js b/app/javascript/controllers/terminal_controller.js
index b90be4cc5..009a14fdf 100644
--- a/app/javascript/controllers/terminal_controller.js
+++ b/app/javascript/controllers/terminal_controller.js
@@ -64,6 +64,7 @@ export default class extends Controller {
   }
 
   hideError() {
+    this.#hideOutput()
     this.element.classList.remove(this.errorClass)
   }
 
@@ -113,13 +114,15 @@ export default class extends Controller {
     const status = response.status
 
     if (status === HttpStatus.UNPROCESSABLE) {
-      this.#showError()
+      this.#showError(response)
     } else if (status === HttpStatus.CONFLICT) {
       await this.#handleConflictResponse(response)
     }
   }
 
-  #showError() {
+  async #showError(response) {
+    const message = await response.json()
+    this.#showOutput(message.error)
     this.element.classList.add(this.errorClass)
   }
 
diff --git a/app/models/command.rb b/app/models/command.rb
index d5a3eacef..3f0640609 100644
--- a/app/models/command.rb
+++ b/app/models/command.rb
@@ -37,8 +37,35 @@ class Command < ApplicationRecord
     false
   end
 
+  def error_messages
+    errors.to_hash.flat_map do |attribute, message|
+      error_message_for(attribute, message)
+    end.uniq
+  end
+
   private
     def redirect_to(...)
       Command::Result::Redirection.new(...)
     end
+
+    def error_message_for(attribute, message)
+      case attribute.to_sym
+      when :cards, :card_ids
+        "No cards in this context"
+      when :card
+        "Can't find the card"
+      when :collection
+        "The collection is missing"
+      when :assignee_ids
+        "Assignees are missing"
+      when :user
+        "Can't find that user"
+      when :stage
+        "Can't find that workflow stage"
+      when :tag_title
+        "A tag is required"
+      else
+        message
+      end
+    end
 end
diff --git a/app/models/command/composite.rb b/app/models/command/composite.rb
index 59256b773..dd696e6bd 100644
--- a/app/models/command/composite.rb
+++ b/app/models/command/composite.rb
@@ -34,6 +34,10 @@ class Command::Composite < Command
     commands.any?(&:needs_confirmation?)
   end
 
+  def error_messages
+    commands.flat_map(&:error_messages).uniq
+  end
+
   private
     def commands_excluding_redirections
       commands.reject { it.is_a?(Command::VisitUrl) }