diff --git a/README.md b/README.md
index 59a3efc..51e61c6 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,11 @@
-**Hello world!!!**
+## Overview
+This block (`block.py`) is responsible for assigning grade for the passed in probability.
+
+## Key Inputs & Outputs
+- **Request**: Refer to `request_schema.json` for detailed input fields and validation rules.  
+- **Response**: Refer to `response_schema.json` for the returned structure and data types.
+
+## Implementation Details
+- All core logic resides in `block.py` within the `__main__` function.
+- Example usage and validation are demonstrated in `test_block.py`.
+
diff --git a/block.py b/block.py
index 3b227f9..17e6ed4 100644
--- a/block.py
+++ b/block.py
@@ -1,21 +1,33 @@
-@flowx_block
-def example_function(request: dict) -> dict:
+import logging
 
-  # Processing logic here...
+# Configure logging
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s [%(levelname)s] %(name)s - %(message)s",
+)
+logger = logging.getLogger(__name__)
 
-  return {
-    "meta_info": [
-      {
-        "name": "created_date",
-        "type": "string",
-        "value": "2024-11-05"
-      }
-    ],
-    "fields": [
-      {
-        "name": "",
-        "type": "",
-        "value": ""
-      }
-    ]
-  }
+def __main__(probability: float) -> dict:
+    logger.info("Received input: probability=%.8f", float(probability))
+    
+    if not isinstance(probability, (int, float)):
+        logger.error("Invalid input type: probability=%s", type(probability).__name__)
+        raise ValueError("Input probability must be a number (int or float)")
+    
+    if probability <= 0.33:
+        grade = "G1"
+    elif 0.33 < probability <= 0.41:
+        grade = "G2"
+    elif 0.41 < probability <= 0.48:
+        grade = "G3"
+    elif 0.48 < probability <= 0.61:
+        grade = "G4"
+    elif 0.61 < probability <= 0.65:
+        grade = "G5"
+    else:
+        grade = "G6"
+        
+    result = {"grade": grade}
+
+    logger.info("Fraud V1 Grade: %s", result)
+    return  result
\ No newline at end of file
diff --git a/request_schema.json b/request_schema.json
index 0967ef4..2f6a8d0 100644
--- a/request_schema.json
+++ b/request_schema.json
@@ -1 +1,11 @@
-{}
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "properties": {
+    "probability": {
+      "type": "number",
+      "description": "Fraud Model predicted score."
+    }
+  },
+  "required": []
+}
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
index 0967ef4..8c4acbc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-{}
+jsonschema==4.23.0
\ No newline at end of file
diff --git a/response_schema.json b/response_schema.json
index 0967ef4..a990940 100644
--- a/response_schema.json
+++ b/response_schema.json
@@ -1 +1,10 @@
-{}
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "properties": {
+    "grade": {
+      "type": "string",
+      "description": "PD v2 grade."
+    }
+  }
+}
\ No newline at end of file
diff --git a/test_block.py b/test_block.py
new file mode 100644
index 0000000..12014c6
--- /dev/null
+++ b/test_block.py
@@ -0,0 +1,15 @@
+import unittest
+from block import __main__
+
+class TestBlock(unittest.TestCase):
+
+    def test_main_success(self):
+        result = __main__(probability=0.3890174329280853)
+        self.assertEqual(result, {"grade": "G2"})
+
+    def test_main_invalid_input(self):
+        with self.assertRaises(ValueError):
+            __main__(probability="0.40")  # Invalid input type (string)
+
+if __name__ == "__main__":
+    unittest.main()