diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c70672e..e090797 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,5 +1,7 @@
 name: ci
 on: [push, pull_request]
+permissions:
+  contents: write
 jobs:
   test:
     runs-on: ubuntu-latest
diff --git a/tencirchem/utils/optimizer.py b/tencirchem/utils/optimizer.py
index f7d03f0..6e64379 100644
--- a/tencirchem/utils/optimizer.py
+++ b/tencirchem/utils/optimizer.py
@@ -9,6 +9,32 @@
 
 
 def soap(fun, x0, args=(), maxfev=2000, callback=None, **kwargs):
+    """
+    Scipy Optimizer interface for sequantial optimization with
+    approximate parabola (SOAP)
+
+    Parameters
+    ----------
+    fun : callable ``f(x, *args)``
+        Function to be optimized.
+    x0 : ndarray, shape (n,)
+        Initial guess. Array of real elements of size (n,),
+        where 'n' is the number of independent variables.
+    args : tuple, optional
+        Extra arguments passed to the objective function.
+    maxfev : int
+        Maximum number of function evaluations to perform.
+        Default: 2000.
+    callback : callable, optional
+        Called after each iteration.
+
+    Returns
+    -------
+    res : OptimizeResult
+        The optimization result represented as a SciPy ``OptimizeResult`` object.
+        Important attributes are: ``x`` the solution array.
+    """
+
     nfev = 0
     nit = 0