diff --git a/otterdog/webapp/webhook/__init__.py b/otterdog/webapp/webhook/__init__.py
index 0db4f438..dbc40a42 100644
--- a/otterdog/webapp/webhook/__init__.py
+++ b/otterdog/webapp/webhook/__init__.py
@@ -88,12 +88,16 @@ async def on_issue_comment_received(data):
     if event.installation is None or event.organization is None:
         return success()
 
+    # currently we only handle comments to pull requests
+    if event.issue.pull_request is None:
+        return success()
+
     otterdog_config = get_otterdog_config()
 
     if event.repository.name != otterdog_config.default_config_repo:
         return success()
 
-    if event.action in ["created", "edited"] and "/pull/" in event.issue.html_url:
+    if event.action in ["created", "edited"]:
         org_id = event.organization.login
         installation_id = event.installation.id
 
diff --git a/otterdog/webapp/webhook/github_models.py b/otterdog/webapp/webhook/github_models.py
index e00cea74..16dd8de0 100644
--- a/otterdog/webapp/webhook/github_models.py
+++ b/otterdog/webapp/webhook/github_models.py
@@ -93,6 +93,13 @@ class Comment(BaseModel):
     updated_at: str
 
 
+class AssociatedPullRequest(BaseModel):
+    """Indicates the associated pull request for an issue comment."""
+
+    url: str
+    html_url: str
+
+
 class Issue(BaseModel):
     """Represents an issue"""
 
@@ -100,8 +107,9 @@ class Issue(BaseModel):
     node_id: str
     title: str
     state: str
-    draft: bool
-    body: Optional[str]
+    draft: Optional[bool] = None
+    body: Optional[str] = None
+    pull_request: Optional[AssociatedPullRequest] = None
     html_url: str