diff --git a/app/gitignore-gen/tests/integration/cli_integration.rs b/app/gitignore-gen/tests/integration/cli_integration.rs
new file mode 100644
index 0000000..fe73893
--- /dev/null
+++ b/app/gitignore-gen/tests/integration/cli_integration.rs
@@ -0,0 +1,276 @@
+use assert_cmd::Command;
+use predicates::prelude::*;
+use std::path::PathBuf;
+
+#[test]
+fn test_generate_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate").assert().success();
+}
+
+#[test]
+fn test_list_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("list").assert().success();
+}
+
+#[test]
+fn test_search_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("search").arg("rust").assert().success();
+}
+
+#[test]
+fn test_interactive_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("interactive").assert().success();
+}
+
+#[test]
+fn test_contribute_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("contribute").arg("test-template").assert().success();
+}
+
+#[test]
+fn test_info_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("info").arg("rust").assert().success();
+}
+
+#[test]
+fn test_update_command_exists() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("update").assert().success();
+}
+
+#[test]
+fn test_generate_with_template() {
+    let temp_dir = tempfile::tempdir().unwrap();
+    let output_file = temp_dir.path().join(".gitignore");
+
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--output")
+        .arg(&output_file)
+        .arg("--template")
+        .arg("rust")
+        .assert()
+        .success();
+
+    assert!(output_file.exists());
+
+    let content = std::fs::read_to_string(&output_file).unwrap();
+    assert!(content.contains("Generated by gitignore-gen"));
+    assert!(content.contains("rust"));
+}
+
+#[test]
+fn test_generate_with_combine() {
+    let temp_dir = tempfile::tempdir().unwrap();
+    let output_file = temp_dir.path().join(".gitignore");
+
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--output")
+        .arg(&output_file)
+        .arg("--combine")
+        .arg("rust,python")
+        .assert()
+        .success();
+
+    assert!(output_file.exists());
+
+    let content = std::fs::read_to_string(&output_file).unwrap();
+    assert!(content.contains("rust"));
+    assert!(content.contains("python"));
+}
+
+#[test]
+fn test_generate_with_custom_patterns() {
+    let temp_dir = tempfile::tempdir().unwrap();
+    let output_file = temp_dir.path().join(".gitignore");
+
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--output")
+        .arg(&output_file)
+        .arg("--template")
+        .arg("rust")
+        .arg("--custom")
+        .arg("*.custom,.idea/")
+        .assert()
+        .success();
+
+    assert!(output_file.exists());
+
+    let content = std::fs::read_to_string(&output_file).unwrap();
+    assert!(content.contains("*.custom"));
+    assert!(content.contains(".idea/"));
+}
+
+#[test]
+fn test_list_shows_templates() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("list")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("rust"));
+}
+
+#[test]
+fn test_list_with_search() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("list")
+        .arg("--search")
+        .arg("rust")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("rust"));
+}
+
+#[test]
+fn test_search_finds_template() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("search")
+        .arg("python")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("python"));
+}
+
+#[test]
+fn test_search_no_results() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("search")
+        .arg("xyznonexistent123")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("No templates found"));
+}
+
+#[test]
+fn test_info_shows_template() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("info")
+        .arg("rust")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("rust"))
+        .stdout(predicate::str::contains("Patterns:"));
+}
+
+#[test]
+fn test_info_nonexistent_template() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("info")
+        .arg("nonexistent")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("not found"));
+}
+
+#[test]
+fn test_update_shows_current_version() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("update")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("up to date"));
+}
+
+#[test]
+fn test_contribute_shows_guidance() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("contribute")
+        .arg("my-template")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("my-template"))
+        .stdout(predicate::str::contains("PR"));
+}
+
+#[test]
+fn test_version_flag() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("--version")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("gitignore-gen"));
+}
+
+#[test]
+fn test_help_flag() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("--help")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("USAGE"))
+        .stdout(predicate::str::contains("SUBCOMMANDS"));
+}
+
+#[test]
+fn test_generate_help() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--help")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("USAGE"))
+        .stdout(predicate::str::contains("--output"))
+        .stdout(predicate::str::contains("--template"));
+}
+
+#[test]
+fn test_list_help() {
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("list")
+        .arg("--help")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("--category"))
+        .stdout(predicate::str::contains("--search"));
+}
+
+#[test]
+fn test_generate_default_output() {
+    let temp_dir = tempfile::tempdir().unwrap();
+    std::env::set_current_dir(&temp_dir).unwrap();
+
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--template")
+        .arg("rust")
+        .assert()
+        .success();
+
+    let gitignore = PathBuf::from(".gitignore");
+    assert!(gitignore.exists());
+
+    let content = std::fs::read_to_string(&gitignore).unwrap();
+    assert!(content.contains("Generated by gitignore-gen"));
+
+    std::env::set_current_dir("/app").unwrap();
+}
+
+#[test]
+fn test_generate_append_custom_patterns() {
+    let temp_dir = tempfile::tempdir().unwrap();
+    let output_file = temp_dir.path().join(".gitignore");
+
+    let mut cmd = Command::cargo_bin("gitignore-gen").unwrap();
+    cmd.arg("generate")
+        .arg("--output")
+        .arg(&output_file)
+        .arg("--template")
+        .arg("rust")
+        .arg("--custom")
+        .arg("*.app")
+        .arg("--append")
+        .assert()
+        .success();
+
+    let content = std::fs::read_to_string(&output_file).unwrap();
+    assert!(content.contains("*.app"));
+    assert!(content.contains("# Custom patterns"));
+}