diff --git a/README.md b/README.md
index 91da9a7..077365c 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,11 @@ python task.py list
 
 # Complete a task
 python task.py done 1
+
+# Emit machine-readable JSON for automation
+python task.py add "Buy groceries" --json
+python task.py list --json
+python task.py done 1 --json
 ```
 
 ## Testing
diff --git a/commands/add.py b/commands/add.py
index 1b1a943..ffaf0fc 100644
--- a/commands/add.py
+++ b/commands/add.py
@@ -1,25 +1,24 @@
 """Add task command."""
-
 import json
 from pathlib import Path
 
 
-def get_tasks_file():
-    """Get path to tasks file."""
-    return Path.home() / ".local" / "share" / "task-cli" / "tasks.json"
-
-
 def validate_description(description):
     """Validate task description."""
-    # NOTE: Validation logic scattered here - should be in utils (refactor bounty)
-    if not description:
+    if not description or not description.strip():
         raise ValueError("Description cannot be empty")
+    description = description.strip()
     if len(description) > 200:
-        raise ValueError("Description too long (max 200 chars)")
-    return description.strip()
+        raise ValueError("Description too long")
+    return description
 
 
-def add_task(description):
+def get_tasks_file():
+    """Get path to tasks file."""
+    return Path.home() / ".local" / "share" / "task-cli" / "tasks.json"
+
+
+def add_task(description, json_output=False):
     """Add a new task."""
     description = validate_description(description)
 
@@ -31,7 +30,11 @@ def add_task(description):
         tasks = json.loads(tasks_file.read_text())
 
     task_id = len(tasks) + 1
-    tasks.append({"id": task_id, "description": description, "done": False})
-
+    task = {"id": task_id, "description": description, "done": False}
+    tasks.append(task)
     tasks_file.write_text(json.dumps(tasks, indent=2))
-    print(f"Added task {task_id}: {description}")
+
+    if json_output:
+        print(json.dumps({"status": "added", "task": task}))
+    else:
+        print(f"Added task {task_id}: {description}")
diff --git a/commands/done.py b/commands/done.py
index c9dfd42..83b8a8c 100644
--- a/commands/done.py
+++ b/commands/done.py
@@ -1,5 +1,4 @@
 """Mark task done command."""
-
 import json
 from pathlib import Path
 
@@ -11,17 +10,19 @@ def get_tasks_file():
 
 def validate_task_id(tasks, task_id):
     """Validate task ID exists."""
-    # NOTE: Validation logic scattered here - should be in utils (refactor bounty)
     if task_id < 1 or task_id > len(tasks):
         raise ValueError(f"Invalid task ID: {task_id}")
     return task_id
 
 
-def mark_done(task_id):
+def mark_done(task_id, json_output=False):
     """Mark a task as complete."""
     tasks_file = get_tasks_file()
     if not tasks_file.exists():
-        print("No tasks found!")
+        if json_output:
+            print(json.dumps({"status": "error", "error": "No tasks found"}))
+        else:
+            print("No tasks found!")
         return
 
     tasks = json.loads(tasks_file.read_text())
@@ -31,7 +32,13 @@ def mark_done(task_id):
         if task["id"] == task_id:
             task["done"] = True
             tasks_file.write_text(json.dumps(tasks, indent=2))
-            print(f"Marked task {task_id} as done: {task['description']}")
+            if json_output:
+                print(json.dumps({"status": "done", "task": task}))
+            else:
+                print(f"Marked task {task_id} as done: {task['description']}")
             return
 
-    print(f"Task {task_id} not found")
+    if json_output:
+        print(json.dumps({"status": "error", "error": f"Task {task_id} not found"}))
+    else:
+        print(f"Task {task_id} not found")
diff --git a/commands/list.py b/commands/list.py
index 714315d..c041020 100644
--- a/commands/list.py
+++ b/commands/list.py
@@ -1,5 +1,4 @@
 """List tasks command."""
-
 import json
 from pathlib import Path
 
@@ -9,24 +8,20 @@ def get_tasks_file():
     return Path.home() / ".local" / "share" / "task-cli" / "tasks.json"
 
 
-def validate_task_file():
-    """Validate tasks file exists."""
-    # NOTE: Validation logic scattered here - should be in utils (refactor bounty)
+def list_tasks(json_output=False):
+    """List all tasks."""
     tasks_file = get_tasks_file()
     if not tasks_file.exists():
-        return []
-    return tasks_file
-
-
-def list_tasks():
-    """List all tasks."""
-    # NOTE: No --json flag support yet (feature bounty)
-    tasks_file = validate_task_file()
-    if not tasks_file:
-        print("No tasks yet!")
+        if json_output:
+            print(json.dumps({"tasks": []}))
+        else:
+            print("No tasks yet!")
         return
 
     tasks = json.loads(tasks_file.read_text())
+    if json_output:
+        print(json.dumps({"tasks": tasks}))
+        return
 
     if not tasks:
         print("No tasks yet!")
diff --git a/task.py b/task.py
index 53cc8ed..21ed983 100644
--- a/task.py
+++ b/task.py
@@ -25,22 +25,25 @@ def main():
     # Add command
     add_parser = subparsers.add_parser("add", help="Add a new task")
     add_parser.add_argument("description", help="Task description")
+    add_parser.add_argument("--json", action="store_true", help="Output result as JSON")
 
     # List command
     list_parser = subparsers.add_parser("list", help="List all tasks")
+    list_parser.add_argument("--json", action="store_true", help="Output result as JSON")
 
     # Done command
     done_parser = subparsers.add_parser("done", help="Mark task as complete")
     done_parser.add_argument("task_id", type=int, help="Task ID to mark done")
+    done_parser.add_argument("--json", action="store_true", help="Output result as JSON")
 
     args = parser.parse_args()
 
     if args.command == "add":
-        add_task(args.description)
+        add_task(args.description, json_output=args.json)
     elif args.command == "list":
-        list_tasks()
+        list_tasks(json_output=args.json)
     elif args.command == "done":
-        mark_done(args.task_id)
+        mark_done(args.task_id, json_output=args.json)
     else:
         parser.print_help()
 
diff --git a/test_json_output.py b/test_json_output.py
new file mode 100644
index 0000000..b27f481
--- /dev/null
+++ b/test_json_output.py
@@ -0,0 +1,38 @@
+"""Tests for JSON output mode."""
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+
+def run_cli(home, *args):
+    result = subprocess.run(
+        [sys.executable, "task.py", *args],
+        cwd=Path(__file__).parent,
+        env={"HOME": str(home)},
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    return result.stdout.strip()
+
+
+def test_json_output_for_add_list_and_done(tmp_path):
+    added = json.loads(run_cli(tmp_path, "add", "Ship feature", "--json"))
+    assert added["status"] == "added"
+    assert added["task"] == {"id": 1, "description": "Ship feature", "done": False}
+
+    listed = json.loads(run_cli(tmp_path, "list", "--json"))
+    assert listed["tasks"] == [added["task"]]
+
+    done = json.loads(run_cli(tmp_path, "done", "1", "--json"))
+    assert done["status"] == "done"
+    assert done["task"] == {"id": 1, "description": "Ship feature", "done": True}
+
+    listed_again = json.loads(run_cli(tmp_path, "list", "--json"))
+    assert listed_again["tasks"] == [done["task"]]
+
+
+def test_json_list_empty_state(tmp_path):
+    listed = json.loads(run_cli(tmp_path, "list", "--json"))
+    assert listed == {"tasks": []}