diff --git a/jaxley/io/graph.py b/jaxley/io/graph.py
index bc510209..40bd22d7 100644
--- a/jaxley/io/graph.py
+++ b/jaxley/io/graph.py
@@ -266,6 +266,23 @@ def split_branches(
 
 
 def insert_compartments(graph: nx.DiGraph, ncomp_per_branch: int) -> nx.DiGraph:
+    """Insert compartment nodes into the graph.
+
+    Inserts new nodes in every branch (edges with "branch_index" attribute) at equidistant
+    points along it. Node attributes, like radius are linearly interpolated along its
+    length.
+
+    Example: 4 compartments | edges = - | nodes = o | comp_nodes = x
+    o-----------o----------o---o---o---o--------o
+    o-------x---o----x-----o--xo---o---ox-------o
+
+    Args:
+        graph: Mmorphology where edges are already labelled with "branch_index"
+        ncomp_per_branch: How many compartments per branch to insert
+
+    Returns:
+        Graph with additional nodes that are labelled with "comp_index"
+    """
     comp_offset = 0
 
     branch_inds = nx.get_edge_attributes(graph, "branch_index")
@@ -319,7 +336,24 @@ def insert_compartments(graph: nx.DiGraph, ncomp_per_branch: int) -> nx.DiGraph:
     return graph
 
 
-def get_comp_edges_dfs(graph, node, parent_comp=None, visited=None):
+def get_comp_edges_dfs(
+    graph: nx.DiGraph, node: int, parent_comp: int = None, visited: set = None
+) -> List[Tuple[int]]:
+    """List edges between compartment nodes, ignoring non-compartment nodes.
+
+    Traverses a graph depth first and only records nodes and their successors if they
+    have a "compartment_index".
+
+    Args:
+        graph: Morphology with inserted compartment nodes.
+        node: node_index from which to start depth first traversal
+        parent_comp: node_index of parent compartment
+        visited: Keeps track of visited nodes during traversal
+
+    Returns:
+        List of edges (parent_node_index, child_node_index) that directly connect
+        compartments, while skipping indermediate hops via nodes w.o. "comp_index" attr.
+    """
     if visited is None:
         visited = set()
     edges = []
@@ -343,7 +377,19 @@ def get_comp_edges_dfs(graph, node, parent_comp=None, visited=None):
     return edges
 
 
-def extract_comp_graph(graph):
+def extract_comp_graph(graph: nx.DiGraph) -> nx.DiGraph:
+    """Get subgraph that only includes compartment nodes and their direct edges.
+
+    Example: 4 compartments | edges = - | nodes = o | comp_nodes = x
+    o-------x---o----x-----o--xo---o---ox-------o
+            x--------x--------x---------x
+
+    Args:
+        graph: Morphology with compartment nodes
+
+    Returns:
+        Morphology with branches and compartments.
+    """
     # create subgraph w.o. edges
     comp_nodes = list(nx.get_node_attributes(graph, "comp_index"))
     comp_graph = nx.subgraph(graph, comp_nodes).copy()