diff --git a/README.md b/README.md
index ea0a730..acb4efb 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,37 @@ Generate & explain git commands using plain english.
 Generated command: git commit -m 'Update README with commit message example and instructions'
 ```
 
+### Generate commit messages as a pre-commit hook
+
+#### Install pre-commit
+
+```shell
+pip install pre-commit
+```
+
+#### Add pre-commit hook
+
+```yaml
+repos:
+  - repo: https://github.com/danthelion/git-genie
+    rev: "v0.3.0"
+    hooks:
+      - id: git-genie
+        args: [ '--mode=append' ]  # or --mode=replace
+```
+
+#### Watch the magic happen
+
+```shell
+~/Personal/git-genie-pre-commit main* ❯ git add . && git commit -m "test"
+
+git-genie................................................................Passed
+
+[main 0dc8c69] test 🧞: Specify specific revision and add '--mode=replace' argument to git-genie hook.
+
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+```
+
 ### Generate & Explain complex git commands using plain english
 
 ![example](example.png)
diff --git a/git_genie/main.py b/git_genie/main.py
index 90003e2..bd458a4 100644
--- a/git_genie/main.py
+++ b/git_genie/main.py
@@ -1,6 +1,5 @@
 import argparse
 import subprocess
-import sys
 
 import typer
 from langchain.chains import LLMChain
@@ -274,7 +273,7 @@ def main(
             )
 
 
-def update_commit_message(filename, mode):
+def update_commit_message(filename: str, mode: str = "append"):
     with open(filename, "r+") as fd:
         contents = fd.readlines()
         commit_msg = contents[0].rstrip("\r\n")
@@ -304,8 +303,8 @@ def pre_commit(argv=None):
     parser.add_argument("filenames", nargs="+")
     parser.add_argument("--mode", nargs="?", const=append, default=append, choices=[append, replace])
     args = parser.parse_args(argv)
-    update_commit_message(args.filenames[0], mode="append")
+    update_commit_message(args.filenames[0], mode=args.mode)
 
 
 if __name__ == "__main__":
-    sys.exit(pre_commit())
+    app()