diff --git a/Cargo.lock b/Cargo.lock
index de6d8d4..6746d87 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2144,6 +2144,7 @@ dependencies = [
  "rstest",
  "serde",
  "serde_json",
+ "serial_test",
  "tempfile",
  "tokio",
  "tracing",
@@ -2285,6 +2286,15 @@ version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 
+[[package]]
+name = "scc"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46e6f046b7fef48e2660c57ed794263155d713de679057f2d0c169bfc6e756cc"
+dependencies = [
+ "sdd",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.28"
@@ -2324,6 +2334,12 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "sdd"
+version = "3.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "490dcfcbfef26be6800d11870ff2df8774fa6e86d047e3e8c8a76b25655e41ca"
+
 [[package]]
 name = "security-framework"
 version = "2.11.1"
@@ -2469,6 +2485,31 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serial_test"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b258109f244e1d6891bf1053a55d63a5cd4f8f4c30cf9a1280989f80e7a1fa9"
+dependencies = [
+ "futures",
+ "log",
+ "once_cell",
+ "parking_lot",
+ "scc",
+ "serial_test_derive",
+]
+
+[[package]]
+name = "serial_test_derive"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d69265a08751de7844521fd15003ae0a888e035773ba05695c5c759a6f89eef"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "sha2"
 version = "0.10.9"
diff --git a/Cargo.toml b/Cargo.toml
index e70a435..40b21d2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@ tracing-subscriber = "0.3"
 
 [dependencies.nix]
 version = "0.30.1"
-features = ["fs"]
+features = ["fs", "resource"]
 
 [dependencies.clap]
 version = "4.5"
@@ -46,6 +46,7 @@ features = [
 
 [dev-dependencies]
 rstest = "0.24"
+serial_test = "3.2"
 tempfile = "3.13"
 
 [dev-dependencies.cargo-husky]
diff --git a/rustfmt.toml b/rustfmt.toml
index a3f43d4..e523805 100644
--- a/rustfmt.toml
+++ b/rustfmt.toml
@@ -2,6 +2,8 @@ edition = "2024"
 style_edition = "2024"
 comment_width = 100
 format_code_in_doc_comments = true
+format_macro_bodies = true
+format_macro_matchers = true
 imports_granularity = "Crate"
 imports_layout = "HorizontalVertical"
 wrap_comments = true
diff --git a/src/setup.rs b/src/setup.rs
index 040bbc3..5f7df13 100644
--- a/src/setup.rs
+++ b/src/setup.rs
@@ -66,7 +66,7 @@ pub struct Args {
     /// IRC Username
     pub username: Option<String>,
 
-    #[arg(long)]
+    #[arg(long = "no-tls")]
     /// Whether or not to use TLS when connecting to the IRC server.
     pub use_tls: Option<bool>,
 }
@@ -87,6 +87,15 @@ pub async fn init() -> Result<Setup> {
     // variables if applicable.
     let args = Args::parse();
 
+    let settings = make_config(args)?;
+
+    Ok(Setup { config: settings })
+}
+
+/// Create a configuration object from arguments.
+///
+/// This is exposed for testing purposes.
+pub fn make_config(args: Args) -> Result<Config> {
     // Use default config location unless specified.
     let config_location: PathBuf = if let Some(ref path) = args.config_file {
         path.to_owned()
@@ -100,7 +109,7 @@ pub async fn init() -> Result<Setup> {
 
     info!("Starting.");
 
-    let settings = Config::builder()
+    Config::builder()
         .add_source(config::File::with_name(&config_location.to_string_lossy()).required(false))
         .add_source(config::Environment::with_prefix("BOT"))
         // Doing all of these overrides provides a unified access point for options,
@@ -110,15 +119,14 @@ pub async fn init() -> Result<Setup> {
         .set_override_option("chroot-dir", args.chroot_dir.clone())?
         .set_override_option("command-path", args.command_dir.clone())?
         .set_override_option("model", args.model.clone())?
+        .set_override_option("nick-password", args.nick_password.clone())?
         .set_override_option("instruct", args.instruct.clone())?
         .set_override_option("channels", args.channels.clone())?
         .set_override_option("server", args.server.clone())?
-        .set_override_option("port", args.port.clone())? // FIXME: Make this a default here not in clap.
+        .set_override_option("port", args.port.clone())?
         .set_override_option("nickname", args.nickname.clone())?
         .set_override_option("username", args.username.clone())?
-        .set_override_option("use_tls", args.use_tls)?
+        .set_override_option("use-tls", args.use_tls)?
         .build()
-        .wrap_err("Couldn't read configuration settings.")?;
-
-    Ok(Setup { config: settings })
+        .wrap_err("Couldn't read configuration settings.")
 }
diff --git a/tests/setup_test.rs b/tests/setup_test.rs
new file mode 100644
index 0000000..e23bc62
--- /dev/null
+++ b/tests/setup_test.rs
@@ -0,0 +1,556 @@
+use robotnik::setup::{Args, make_config};
+use serial_test::serial;
+use std::{fs, path::PathBuf};
+use tempfile::TempDir;
+
+/// Helper to create a temporary config file
+fn create_config_file(dir: &TempDir, content: &str) -> PathBuf {
+    let config_path = dir.path().join("config.toml");
+    fs::write(&config_path, content).unwrap();
+    config_path
+}
+
+/// Helper to parse config using environment and config file
+async fn parse_config_from_file(config_path: &PathBuf) -> config::Config {
+    config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .build()
+        .unwrap()
+}
+
+#[tokio::test]
+#[serial]
+async fn test_setup_make_config_overrides() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api-key = \"file-key\"
+model = \"file-model\"
+port = 6667
+";
+    let config_path = create_config_file(&temp, config_content);
+
+    // Construct Args with overrides
+    let args = Args {
+        api_key: Some("cli-key".to_string()),
+        base_url: None, /* Should fail if required and not in file/env? No, base-url is optional
+                         * in args */
+        chroot_dir: None,
+        command_dir: None,
+        instruct: None,
+        model: None, // Should fallback to file
+        channels: None,
+        config_file: Some(config_path),
+        server: None, // Should use default or file? Args has default "irc.libera.chat"
+        port: Some("9999".to_string()),
+        nickname: None,
+        nick_password: None,
+        username: None,
+        use_tls: None,
+    };
+
+    let config = make_config(args).expect("Failed to make config");
+
+    // Check overrides
+    assert_eq!(config.get_string("api-key").unwrap(), "cli-key");
+    assert_eq!(config.get_string("port").unwrap(), "9999");
+    assert_eq!(config.get_int("port").unwrap(), 9999);
+
+    // Check fallback to file
+    assert_eq!(config.get_string("model").unwrap(), "file-model");
+}
+
+#[tokio::test]
+async fn test_config_file_loads_all_settings() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api-key = \"test-api-key-123\"
+base-url = \"https://api.test.com\"
+chroot-dir = \"/test/chroot\"
+command-path = \"/test/commands\"
+model = \"test-model\"
+instruct = \"Test instructions\"
+server = \"test.irc.server\"
+port = 6667
+channels = [\"#test1\", \"#test2\"]
+username = \"testuser\"
+nickname = \"testnick\"
+use-tls = false
+";
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    // Verify all settings are loaded correctly
+    assert_eq!(config.get_string("api-key").unwrap(), "test-api-key-123");
+    assert_eq!(
+        config.get_string("base-url").unwrap(),
+        "https://api.test.com"
+    );
+    assert_eq!(config.get_string("chroot-dir").unwrap(), "/test/chroot");
+    assert_eq!(config.get_string("command-path").unwrap(), "/test/commands");
+    assert_eq!(config.get_string("model").unwrap(), "test-model");
+    assert_eq!(config.get_string("instruct").unwrap(), "Test instructions");
+    assert_eq!(config.get_string("server").unwrap(), "test.irc.server");
+    assert_eq!(config.get_int("port").unwrap(), 6667);
+
+    let channels: Vec<String> = config.get("channels").unwrap();
+    assert_eq!(channels, vec!["#test1", "#test2"]);
+
+    assert_eq!(config.get_string("username").unwrap(), "testuser");
+    assert_eq!(config.get_string("nickname").unwrap(), "testnick");
+    assert_eq!(config.get_bool("use-tls").unwrap(), false);
+}
+
+#[tokio::test]
+async fn test_config_file_partial_settings() {
+    let temp = TempDir::new().unwrap();
+    // Only provide required settings
+    let config_content = "\
+api-key = \"minimal-key\"
+base-url = \"https://minimal.api.com\"
+model = \"minimal-model\"
+server = \"minimal.server\"
+port = 6697
+channels = [\"#minimal\"]
+";
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    // Verify required settings are loaded
+    assert_eq!(config.get_string("api-key").unwrap(), "minimal-key");
+    assert_eq!(
+        config.get_string("base-url").unwrap(),
+        "https://minimal.api.com"
+    );
+    assert_eq!(config.get_string("model").unwrap(), "minimal-model");
+
+    // Verify optional settings are not present
+    assert!(config.get_string("chroot-dir").is_err());
+    assert!(config.get_string("instruct").is_err());
+    assert!(config.get_string("username").is_err());
+}
+
+#[tokio::test]
+#[serial]
+async fn test_config_with_environment_variables() {
+    // NOTE: This test documents a limitation in setup.rs
+    // setup.rs uses Environment::with_prefix("BOT") without a separator
+    // This means BOT_API_KEY maps to "api_key", NOT "api-key"
+    // Since config.toml uses kebab-case, environment variables won't override properly
+    // This is a known issue in the current implementation
+
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api_key = \"file-api-key\"
+base_url = \"https://file.api.com\"
+model = \"file-model\"
+";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Set environment variables (with BOT_ prefix as setup.rs uses)
+    unsafe {
+        std::env::set_var("BOT_API_KEY", "env-api-key");
+        std::env::set_var("BOT_MODEL", "env-model");
+    }
+
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .add_source(config::Environment::with_prefix("BOT"))
+        .build()
+        .unwrap();
+
+    // Environment variables should override file settings (when using underscore keys)
+    assert_eq!(config.get_string("api_key").unwrap(), "env-api-key");
+    assert_eq!(config.get_string("model").unwrap(), "env-model");
+    // File setting should be used when no env var
+    assert_eq!(
+        config.get_string("base_url").unwrap(),
+        "https://file.api.com"
+    );
+
+    // Cleanup
+    unsafe {
+        std::env::remove_var("BOT_API_KEY");
+        std::env::remove_var("BOT_MODEL");
+    }
+}
+
+#[tokio::test]
+async fn test_command_line_overrides_config_file() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api-key = \"file-api-key\"
+base-url = \"https://file.api.com\"
+model = \"file-model\"
+server = \"file.server\"
+port = 6667
+channels = [\"#file\"]
+nickname = \"filenick\"
+username = \"fileuser\"
+";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Simulate command-line arguments overriding config file
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .set_override_option("api-key", Some("cli-api-key".to_string()))
+        .unwrap()
+        .set_override_option("model", Some("cli-model".to_string()))
+        .unwrap()
+        .set_override_option("server", Some("cli.server".to_string()))
+        .unwrap()
+        .set_override_option("nickname", Some("clinick".to_string()))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    // Command-line values should override file settings
+    assert_eq!(config.get_string("api-key").unwrap(), "cli-api-key");
+    assert_eq!(config.get_string("model").unwrap(), "cli-model");
+    assert_eq!(config.get_string("server").unwrap(), "cli.server");
+    assert_eq!(config.get_string("nickname").unwrap(), "clinick");
+
+    // Non-overridden values should come from file
+    assert_eq!(
+        config.get_string("base-url").unwrap(),
+        "https://file.api.com"
+    );
+    assert_eq!(config.get_string("username").unwrap(), "fileuser");
+    assert_eq!(config.get_int("port").unwrap(), 6667);
+}
+
+#[tokio::test]
+#[serial]
+async fn test_command_line_overrides_environment_and_file() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api_key = \"file-api-key\"
+model = \"file-model\"
+base_url = \"https://file.api.com\"
+";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Set environment variable
+    unsafe {
+        std::env::set_var("BOT_API_KEY", "env-api-key");
+    }
+
+    // Build config with all three sources
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .add_source(config::Environment::with_prefix("BOT"))
+        .set_override_option("api_key", Some("cli-api-key".to_string()))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    // Command-line should win over both environment and file
+    assert_eq!(config.get_string("api_key").unwrap(), "cli-api-key");
+
+    // Cleanup
+    unsafe {
+        std::env::remove_var("BOT_API_KEY");
+    }
+}
+
+#[tokio::test]
+#[serial]
+async fn test_precedence_order() {
+    // Test: CLI > Environment > Config File > Defaults
+    // Using underscore keys to match how setup.rs actually works
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api_key = \"file-key\"
+base_url = \"https://file-url.com\"
+model = \"file-model\"
+server = \"file-server\"
+";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Set environment variables
+    unsafe {
+        std::env::set_var("BOT_BASE_URL", "https://env-url.com");
+        std::env::set_var("BOT_MODEL", "env-model");
+    }
+
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .add_source(config::Environment::with_prefix("BOT"))
+        .set_override_option("model", Some("cli-model".to_string()))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    // CLI overrides everything
+    assert_eq!(config.get_string("model").unwrap(), "cli-model");
+
+    // Environment overrides file
+    assert_eq!(
+        config.get_string("base_url").unwrap(),
+        "https://env-url.com"
+    );
+
+    // File is used when no env or CLI
+    assert_eq!(config.get_string("api_key").unwrap(), "file-key");
+    assert_eq!(config.get_string("server").unwrap(), "file-server");
+
+    // Cleanup
+    unsafe {
+        std::env::remove_var("BOT_BASE_URL");
+        std::env::remove_var("BOT_MODEL");
+    }
+}
+
+#[tokio::test]
+async fn test_boolean_use_tls_setting() {
+    let temp = TempDir::new().unwrap();
+
+    // Test with use-tls = true (kebab-case as in config.toml)
+    let config_content_true = r#"
+use-tls = true
+"#;
+    let config_path = create_config_file(&temp, config_content_true);
+    let config = parse_config_from_file(&config_path).await;
+    assert_eq!(config.get_bool("use-tls").unwrap(), true);
+
+    // Test with use-tls = false
+    let config_content_false = r#"
+use-tls = false
+"#;
+    let config_path = create_config_file(&temp, config_content_false);
+    let config = parse_config_from_file(&config_path).await;
+    assert_eq!(config.get_bool("use-tls").unwrap(), false);
+}
+
+#[tokio::test]
+async fn test_use_tls_naming_inconsistency() {
+    // This test documents a bug: setup.rs uses "use_tls" (underscore)
+    // but config.toml uses "use-tls" (kebab-case)
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+use-tls = true
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Build config the way setup.rs does it
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        // setup.rs line 119 uses "use_tls" (underscore) instead of "use-tls" (kebab)
+        .set_override_option("use_tls", Some(false))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    // This should read from the override (false), not the file (true)
+    // But due to the naming mismatch, it might not work as expected
+    // The config file uses "use-tls" but the override uses "use_tls"
+
+    // With kebab-case (matches config.toml)
+    assert_eq!(config.get_bool("use-tls").unwrap(), true);
+
+    // With underscore (matches setup.rs override)
+    assert_eq!(config.get_bool("use_tls").unwrap(), false);
+}
+
+#[tokio::test]
+async fn test_channels_as_array() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+channels = [\"#chan1\", \"#chan2\", \"#chan3\"]
+";
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    let channels: Vec<String> = config.get("channels").unwrap();
+    assert_eq!(channels.len(), 3);
+    assert_eq!(channels[0], "#chan1");
+    assert_eq!(channels[1], "#chan2");
+    assert_eq!(channels[2], "#chan3");
+}
+
+#[tokio::test]
+async fn test_channels_override_from_cli() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+channels = [\"#file1\", \"#file2\"]
+";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    let cli_channels = vec![
+        "#cli1".to_string(),
+        "#cli2".to_string(),
+        "#cli3".to_string(),
+    ];
+
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .set_override_option("channels", Some(cli_channels.clone()))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    let channels: Vec<String> = config.get("channels").unwrap();
+    assert_eq!(channels, cli_channels);
+    assert_eq!(channels.len(), 3);
+}
+
+#[tokio::test]
+async fn test_port_as_integer() {
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+port = 6697
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    // Port should be readable as both integer and string
+    assert_eq!(config.get_int("port").unwrap(), 6697);
+    assert_eq!(config.get_string("port").unwrap(), "6697");
+}
+
+#[tokio::test]
+async fn test_port_override_from_cli_as_string() {
+    // setup.rs passes port as Option<String> from clap
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+port = 6667
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+
+    let config = config::Config::builder()
+        .add_source(config::File::with_name(&config_path.to_string_lossy()).required(true))
+        .set_override_option("port", Some("9999".to_string()))
+        .unwrap()
+        .build()
+        .unwrap();
+
+    // CLI override should work
+    assert_eq!(config.get_string("port").unwrap(), "9999");
+    assert_eq!(config.get_int("port").unwrap(), 9999);
+}
+
+#[tokio::test]
+async fn test_missing_required_fields_fails() {
+    let temp = TempDir::new().unwrap();
+    // Create config without required api-key
+    let config_content = r#"
+model = "test-model"
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    // Should fail when trying to get required field
+    assert!(config.get_string("api-key").is_err());
+}
+
+#[tokio::test]
+async fn test_optional_instruct_field() {
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+instruct = "Custom bot instructions"
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    assert_eq!(
+        config.get_string("instruct").unwrap(),
+        "Custom bot instructions"
+    );
+}
+
+#[tokio::test]
+async fn test_command_path_field() {
+    // command-path is in config.toml but not used anywhere in the code
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+command-path = "/custom/commands"
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    assert_eq!(
+        config.get_string("command-path").unwrap(),
+        "/custom/commands"
+    );
+}
+
+#[tokio::test]
+async fn test_chroot_dir_field() {
+    let temp = TempDir::new().unwrap();
+    let config_content = r#"
+chroot-dir = "/var/lib/bot/root"
+"#;
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    assert_eq!(
+        config.get_string("chroot-dir").unwrap(),
+        "/var/lib/bot/root"
+    );
+}
+
+#[tokio::test]
+async fn test_empty_config_file() {
+    let temp = TempDir::new().unwrap();
+    let config_content = "";
+
+    let config_path = create_config_file(&temp, config_content);
+
+    // Should build successfully but have no values
+    let config = parse_config_from_file(&config_path).await;
+
+    assert!(config.get_string("api-key").is_err());
+    assert!(config.get_string("model").is_err());
+}
+
+#[tokio::test]
+async fn test_all_cli_override_keys_match_config_format() {
+    // This test documents which override keys in setup.rs match the config.toml format
+    let temp = TempDir::new().unwrap();
+    let config_content = "\
+api-key = \"test\"
+base-url = \"https://test.com\"
+chroot-dir = \"/test\"
+command-path = \"/cmds\"
+model = \"test-model\"
+instruct = \"test\"
+channels = [\"#test\"]
+server = \"test.server\"
+port = 6697
+nickname = \"test\"
+username = \"test\"
+use-tls = true
+";
+
+    let config_path = create_config_file(&temp, config_content);
+    let config = parse_config_from_file(&config_path).await;
+
+    // All these should work with kebab-case (as in config.toml)
+    assert!(config.get_string("api-key").is_ok());
+    assert!(config.get_string("base-url").is_ok());
+    assert!(config.get_string("chroot-dir").is_ok());
+    assert!(config.get_string("command-path").is_ok());
+    assert!(config.get_string("model").is_ok());
+    assert!(config.get_string("instruct").is_ok());
+    let channels_result: Result<Vec<String>, _> = config.get("channels");
+    assert!(channels_result.is_ok());
+    assert!(config.get_string("server").is_ok());
+    assert!(config.get_int("port").is_ok());
+    assert!(config.get_string("nickname").is_ok());
+    assert!(config.get_string("username").is_ok());
+    assert!(config.get_bool("use-tls").is_ok());
+}