feat(tui): add configurable diff backgrounds

codex-rs/core/config.schema.json

@@ -530,6 +530,15 @@
       },
       "type": "object"
     },
+    "DiffBackgroundMode": {
+      "enum": [
+        "auto",
+        "off",
+        "theme",
+        "custom"
+      ],
+      "type": "string"
+    },
     "FeedbackConfigToml": {
       "additionalProperties": false,
       "properties": {
@@ -1396,6 +1405,25 @@
           "description": "Enable animations (welcome screen, shimmer effects, spinners). Defaults to `true`.",
           "type": "boolean"
         },
+        "diff_add_bg": {
+          "default": null,
+          "description": "Custom insert-line background color (`#RRGGBB`).\n\nUsed when `diff_background = \"custom\"`.",
+          "type": "string"
+        },
+        "diff_background": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/DiffBackgroundMode"
+            }
+          ],
+          "default": "auto",
+          "description": "Controls how diff add/remove backgrounds are rendered in the TUI.\n\n- `auto` (default): Use built-in adaptive add/remove backgrounds. - `off`: Disable add/remove line backgrounds. - `theme`: Derive add/remove backgrounds from the active syntax theme (`markup.inserted`/`markup.deleted` with diff fallbacks). - `custom`: Use user-provided custom colors from `diff_add_bg` / `diff_del_bg`."
+        },
+        "diff_del_bg": {
+          "default": null,
+          "description": "Custom delete-line background color (`#RRGGBB`).\n\nUsed when `diff_background = \"custom\"`.",
+          "type": "string"
+        },
         "notification_method": {
           "allOf": [
             {

codex-rs/core/src/config/mod.rs

@@ -3,6 +3,7 @@ use crate::config::edit::ConfigEdit;
 use crate::config::edit::ConfigEditsBuilder;
 use crate::config::types::AppsConfigToml;
 use crate::config::types::DEFAULT_OTEL_ENVIRONMENT;
+use crate::config::types::DiffBackgroundMode;
 use crate::config::types::History;
 use crate::config::types::McpServerConfig;
 use crate::config::types::McpServerDisabledReason;
@@ -298,6 +299,15 @@ pub struct Config {
     /// Syntax highlighting theme override (kebab-case name).
     pub tui_theme: Option<String>,
 
+    /// Controls how diff add/remove backgrounds are rendered in the TUI.
+    pub tui_diff_background: DiffBackgroundMode,
+
+    /// Custom insert-line background color (`#RRGGBB`).
+    pub tui_diff_add_bg: Option<String>,
+
+    /// Custom delete-line background color (`#RRGGBB`).
+    pub tui_diff_del_bg: Option<String>,
+
     /// The directory that should be treated as the current working directory
     /// for the session. All relative paths inside the business-logic layer are
     /// resolved against this path.
@@ -2197,6 +2207,13 @@ impl Config {
                 .unwrap_or_default(),
             tui_status_line: cfg.tui.as_ref().and_then(|t| t.status_line.clone()),
             tui_theme: cfg.tui.as_ref().and_then(|t| t.theme.clone()),
+            tui_diff_background: cfg
+                .tui
+                .as_ref()
+                .map(|t| t.diff_background)
+                .unwrap_or_default(),
+            tui_diff_add_bg: cfg.tui.as_ref().and_then(|t| t.diff_add_bg.clone()),
+            tui_diff_del_bg: cfg.tui.as_ref().and_then(|t| t.diff_del_bg.clone()),
             otel: {
                 let t: OtelConfigToml = cfg.otel.unwrap_or_default();
                 let log_user_prompt = t.log_user_prompt.unwrap_or(false);
@@ -2622,6 +2639,22 @@ theme = "dracula"
         assert_eq!(parsed.tui.as_ref().and_then(|t| t.theme.as_deref()), None);
     }
 
+    #[test]
+    fn tui_diff_background_deserializes_from_toml() {
+        let cfg = r##"
+[tui]
+diff_background = "custom"
+diff_add_bg = "#213A2B"
+diff_del_bg = "#4A221D"
+"##;
+        let parsed =
+            toml::from_str::<ConfigToml>(cfg).expect("TOML deserialization should succeed");
+        let tui = parsed.tui.expect("config should include tui section");
+        assert_eq!(tui.diff_background, DiffBackgroundMode::Custom);
+        assert_eq!(tui.diff_add_bg.as_deref(), Some("#213A2B"));
+        assert_eq!(tui.diff_del_bg.as_deref(), Some("#4A221D"));
+    }
+
     #[test]
     fn tui_config_missing_notifications_field_defaults_to_enabled() {
         let cfg = r#"
@@ -2639,9 +2672,42 @@ theme = "dracula"
                 notification_method: NotificationMethod::Auto,
                 animations: true,
                 show_tooltips: true,
+                show_compact_summary: true,
+                alternate_screen: AltScreenMode::Auto,
+                status_line: None,
+                theme: None,
+                diff_background: DiffBackgroundMode::Auto,
+                diff_add_bg: None,
+                diff_del_bg: None,
+            }
+        );
+    }
+
+    #[test]
+    fn tui_config_can_disable_compact_summary() {
+        let cfg = r#"
+[tui]
+show_compact_summary = false
+"#;
+
+        let parsed = toml::from_str::<ConfigToml>(cfg)
+            .expect("TUI config with show_compact_summary should succeed");
+        let tui = parsed.tui.expect("config should include tui section");
+
+        assert_eq!(
+            tui,
+            Tui {
+                notifications: Notifications::Enabled(true),
+                notification_method: NotificationMethod::Auto,
+                animations: true,
+                show_tooltips: true,
+                show_compact_summary: false,
                 alternate_screen: AltScreenMode::Auto,
                 status_line: None,
                 theme: None,
+                diff_background: DiffBackgroundMode::Auto,
+                diff_add_bg: None,
+                diff_del_bg: None,
             }
         );
     }
@@ -4799,6 +4865,9 @@ model_verbosity = "high"
                 tui_alternate_screen: AltScreenMode::Auto,
                 tui_status_line: None,
                 tui_theme: None,
+                tui_diff_background: DiffBackgroundMode::Auto,
+                tui_diff_add_bg: None,
+                tui_diff_del_bg: None,
                 otel: OtelConfig::default(),
             },
             o3_profile_config
@@ -4925,6 +4994,9 @@ model_verbosity = "high"
             tui_alternate_screen: AltScreenMode::Auto,
             tui_status_line: None,
             tui_theme: None,
+            tui_diff_background: DiffBackgroundMode::Auto,
+            tui_diff_add_bg: None,
+            tui_diff_del_bg: None,
             otel: OtelConfig::default(),
         };
 
@@ -5049,6 +5121,9 @@ model_verbosity = "high"
             tui_alternate_screen: AltScreenMode::Auto,
             tui_status_line: None,
             tui_theme: None,
+            tui_diff_background: DiffBackgroundMode::Auto,
+            tui_diff_add_bg: None,
+            tui_diff_del_bg: None,
             otel: OtelConfig::default(),
         };
 
@@ -5159,6 +5234,9 @@ model_verbosity = "high"
             tui_alternate_screen: AltScreenMode::Auto,
             tui_status_line: None,
             tui_theme: None,
+            tui_diff_background: DiffBackgroundMode::Auto,
+            tui_diff_add_bg: None,
+            tui_diff_del_bg: None,
             otel: OtelConfig::default(),
         };
 

codex-rs/core/src/config/types.rs

@@ -697,6 +697,39 @@ pub struct Tui {
     /// Use `/theme` in the TUI or see `$CODEX_HOME/themes` for custom themes.
     #[serde(default)]
     pub theme: Option<String>,
+
+    /// Controls how diff add/remove backgrounds are rendered in the TUI.
+    ///
+    /// - `auto` (default): Use built-in adaptive add/remove backgrounds.
+    /// - `off`: Disable add/remove line backgrounds.
+    /// - `theme`: Derive add/remove backgrounds from the active syntax theme
+    ///   (`markup.inserted`/`markup.deleted` with diff fallbacks).
+    /// - `custom`: Use user-provided custom colors from `diff_add_bg` /
+    ///   `diff_del_bg`.
+    #[serde(default)]
+    pub diff_background: DiffBackgroundMode,
+
+    /// Custom insert-line background color (`#RRGGBB`).
+    ///
+    /// Used when `diff_background = "custom"`.
+    #[serde(default)]
+    pub diff_add_bg: Option<String>,
+
+    /// Custom delete-line background color (`#RRGGBB`).
+    ///
+    /// Used when `diff_background = "custom"`.
+    #[serde(default)]
+    pub diff_del_bg: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, Default, JsonSchema)]
+#[serde(rename_all = "kebab-case")]
+pub enum DiffBackgroundMode {
+    #[default]
+    Auto,
+    Off,
+    Theme,
+    Custom,
 }
 
 const fn default_true() -> bool {