diff --git a/frontends/API.md b/frontends/API.md
index f65beca..6ef0170 100644
--- a/frontends/API.md
+++ b/frontends/API.md
@@ -107,7 +107,7 @@ Host: localhost:8000
 
 ```json
 {
-  "version": "2.0.0",
+  "version": "2.0.1",
   "has_argon2": true,
   "day_names": ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
 }
@@ -271,7 +271,8 @@ Content-Type: application/json
   "stego_image_base64": "iVBORw0KGgo...",
   "filename": "a1b2c3d4_20251227.png",
   "capacity_used_percent": 12.4,
-  "date_used": "2025-12-27"
+  "date_used": "2025-12-27",
+  "day_of_week": "Saturday"
 }
 ```
 
@@ -282,7 +283,8 @@ Content-Type: application/json
 | `stego_image_base64` | string | Base64-encoded stego PNG |
 | `filename` | string | Suggested filename |
 | `capacity_used_percent` | float | Percentage of capacity used |
-| `date_used` | string | Date embedded in image |
+| `date_used` | string | Date embedded in image (YYYY-MM-DD) |
+| `day_of_week` | string | Day name for passphrase rotation |
 
 #### cURL Example
 
@@ -360,6 +362,9 @@ Content-Type: image/png
 Returns the PNG image directly with headers:
 - `Content-Type: image/png`
 - `Content-Disposition: attachment; filename=<generated_filename>.png`
+- `X-Stegasoo-Date: 2025-12-27` (date used for encoding)
+- `X-Stegasoo-Day: Saturday` (day of week for passphrase rotation)
+- `X-Stegasoo-Capacity-Percent: 12.4` (capacity used)
 
 #### cURL Examples
 
@@ -624,7 +629,8 @@ curl -X POST http://localhost:8000/image/info \
   "stego_image_base64": "string",
   "filename": "string",
   "capacity_used_percent": 12.4,
-  "date_used": "YYYY-MM-DD"
+  "date_used": "YYYY-MM-DD",
+  "day_of_week": "Saturday"
 }
 ```
 
diff --git a/frontends/api/main.py b/frontends/api/main.py
index a139bba..72d9f81 100644
--- a/frontends/api/main.py
+++ b/frontends/api/main.py
@@ -24,6 +24,7 @@ import stegasoo
 from stegasoo import (
     encode, decode, generate_credentials,
     validate_image, calculate_capacity,
+    get_day_from_date,
     DAY_NAMES, __version__,
     StegasooError, DecryptionError, CapacityError,
     has_argon2,
@@ -83,6 +84,7 @@ class EncodeResponse(BaseModel):
     filename: str
     capacity_used_percent: float
     date_used: str
+    day_of_week: str
 
 
 class DecodeRequest(BaseModel):
@@ -193,11 +195,15 @@ async def api_encode(request: EncodeRequest):
         
         stego_b64 = base64.b64encode(result.stego_image).decode('utf-8')
         
+        # Get day of week from the date used
+        day_of_week = get_day_from_date(result.date_used)
+        
         return EncodeResponse(
             stego_image_base64=stego_b64,
             filename=result.filename,
             capacity_used_percent=result.capacity_percent,
-            date_used=result.date_used
+            date_used=result.date_used,
+            day_of_week=day_of_week
         )
         
     except CapacityError as e:
@@ -253,7 +259,7 @@ async def api_encode_multipart(
     """
     Encode using multipart form data (file uploads).
     
-    Returns the stego image directly as PNG.
+    Returns the stego image directly as PNG with metadata headers.
     """
     try:
         ref_data = await reference_photo.read()
@@ -271,10 +277,18 @@ async def api_encode_multipart(
             date_str=date_str if date_str else None
         )
         
+        # Get day of week from the date used
+        day_of_week = get_day_from_date(result.date_used)
+        
         return Response(
             content=result.stego_image,
             media_type="image/png",
-            headers={"Content-Disposition": f"attachment; filename={result.filename}"}
+            headers={
+                "Content-Disposition": f"attachment; filename={result.filename}",
+                "X-Stegasoo-Date": result.date_used,
+                "X-Stegasoo-Day": day_of_week,
+                "X-Stegasoo-Capacity-Percent": f"{result.capacity_percent:.1f}"
+            }
         )
         
     except CapacityError as e:
diff --git a/pyproject.toml b/pyproject.toml
index 4a98148..77f6d70 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "stegasoo"
-version = "2.0.0"
+version = "2.0.1"
 description = "Secure steganography with hybrid photo + passphrase + PIN authentication"
 readme = "README.md"
 license = "MIT"
diff --git a/src/stegasoo/constants.py b/src/stegasoo/constants.py
index 0e24333..5570c28 100644
--- a/src/stegasoo/constants.py
+++ b/src/stegasoo/constants.py
@@ -11,7 +11,7 @@ from pathlib import Path
 # VERSION
 # ============================================================================
 
-__version__ = "2.0.0"
+__version__ = "2.0.1"
 
 # ============================================================================
 # FILE FORMAT
diff --git a/tests/test_stegasoo.py b/tests/test_stegasoo.py
index f9ea972..7c9217a 100644
--- a/tests/test_stegasoo.py
+++ b/tests/test_stegasoo.py
@@ -208,7 +208,7 @@ class TestVersion:
     
     def test_version_exists(self):
         assert hasattr(stegasoo, '__version__')
-        assert stegasoo.__version__ == "2.0.0"
+        assert stegasoo.__version__ == "2.0.1"
     
     def test_day_names(self):
         assert len(stegasoo.DAY_NAMES) == 7