diff --git a/opencode.json b/opencode.json
new file mode 100644
index 0000000..15be39d
--- /dev/null
+++ b/opencode.json
@@ -0,0 +1,16 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "provider": {
+    "thn": {
+      "npm": "@ai-sdk/openai-compatible",
+      "options": {
+        "baseURL": "http://141.75.33.244:8000/v1",
+        "apiKey": "sk-QXj1p40XOwNSze_5-eYrBzVh3qIgAfqoWPkAjNVqOS8"
+      },
+      "models": {
+        "gpt-oss:20b": { "name": "GPT-OSS 20B" }
+      }
+    }
+  },
+  "model": "thn/gpt-oss:20b"
+}
\ No newline at end of file
diff --git a/src/matrixmania/__init__.py b/src/matrixmania/__init__.py
index d74c98f..42bb67e 100644
--- a/src/matrixmania/__init__.py
+++ b/src/matrixmania/__init__.py
@@ -1 +1 @@
-from .compute import matmul, transpose, rot_2d
+from .compute import matmul, rot_2d, transpose, rot_3d
diff --git a/src/matrixmania/compute.py b/src/matrixmania/compute.py
index c2a64a8..51c9f04 100644
--- a/src/matrixmania/compute.py
+++ b/src/matrixmania/compute.py
@@ -14,13 +14,6 @@ from __future__ import annotations
 
 Matrix = list[list[float]]
 
-def main():
-    a = [[1, 2, 3], [4, 5, 6]]
-    b = [[7, 8], [10, 11], [12, 13]]
-    print(matmul(a,b))
-    print(rotate(a))
-    print(transpose(a))
-
 def matmul(a: Matrix, b: Matrix) -> Matrix:
     """Return the product of two matrices.
 
@@ -119,7 +112,66 @@ def rot_2d(matrix: Matrix) -> Matrix:
     transposed = transpose(matrix)
     return [list(reversed(row)) for row in transposed]
 
-if __name__ == "__main__":
-    main()
+def rot_3d(matrix: Matrix, angle: float, axis: str) -> Matrix:
+    """Return a new matrix rotated around the specified axis.
+
+    Parameters
+    ----------
+    matrix: Matrix
+        Matrix of 3‑element vectors to be rotated.
+    angle: float
+        Rotation angle in degrees.
+    axis: str
+        Axis to rotate around. Must be ``'x'``, ``'y'`` or ``'z'``.
+
+    Returns
+    -------
+    Matrix
+        Rotated matrix of 3‑element vectors.
+
+    Raises
+    ------
+    ValueError
+        If the input matrix is empty, rows are not of length 3, or the axis is invalid.
+    """
+    import math
+
+    if not isinstance(angle, (int, float)):
+        raise ValueError("angle must be a numeric value")
+    if not isinstance(axis, str):
+        raise ValueError("axis must be a string")
+
+    rad = math.radians(angle)
+    c = math.cos(rad)
+    s = math.sin(rad)
+
+    axis = axis.lower()
+    if axis == "x":
+        rot = [[1, 0, 0],
+               [0, c, -s],
+               [0, s, c]]
+    elif axis == "y":
+        rot = [[c, 0, s],
+               [0, 1, 0],
+               [-s, 0, c]]
+    elif axis == "z":
+        rot = [[c, -s, 0],
+               [s, c, 0],
+               [0, 0, 1]]
+    else:
+        raise ValueError("axis must be one of 'x', 'y', or 'z'")
+
+    if not matrix or not all(isinstance(row, list) for row in matrix):
+        raise ValueError("Input must be a list of rows")
+    if not all(len(row) == 3 for row in matrix):
+        raise ValueError("Each row must contain exactly 3 elements")
+
+    result: Matrix = []
+    for vec in matrix:
+        if any(not isinstance(v, (int, float)) for v in vec):
+            raise ValueError("All coordinates must be numeric")
+        rotated = [sum(v * r for v, r in zip(vec, col)) for col in zip(*rot)]
+        result.append([float(x) for x in rotated])
+    return result
 
 """End of module"""
diff --git a/test/test_matrixmania/test_rot.py b/test/test_matrixmania/test_rot.py
new file mode 100644
index 0000000..b8c770e
--- /dev/null
+++ b/test/test_matrixmania/test_rot.py
@@ -0,0 +1,13 @@
+from src.matrixmania.compute import *
+
+def test_matmul():
+    a = [[1, 2, 3], [4, 5, 6]]
+    b = [[7, 8], [10, 11], [12, 13]]
+
+    expected_value = []
+    expected_type = Matrix
+
+    result = matmul(a,b)
+
+    assert result == expected_value
+    assert isinstance(result, expected_type)
\ No newline at end of file