feat(wm): add global layout_defaults for per-layout default options

Adds a top-level layout_defaults setting that defines default layout_options and layout_options_rules per layout. Workspaces without their own layout_options or layout_options_rules automatically inherit the global defaults. If a workspace defines either setting, all global defaults for that layout are fully replaced.
feat(wm): add threshold-based layout_options_rules for workspaces
2026-05-04 09:54:17 +02:00 · 2026-05-03 10:16:20 -07:00 · 2026-05-03 10:16:18 -07:00
10 changed files with 1367 additions and 378 deletions
--- a/docs/common-workflows/layout-ratios.md
+++ b/docs/common-workflows/layout-ratios.md
@@ -172,6 +172,143 @@ consistently to all splits of that type throughout the layout. Additional values
 - Unspecified ratios default to sharing the remaining space equally
 - You only need to specify the ratios you want to customize; trailing values can be omitted

+## Layout Options Rules
+
+You can dynamically change `layout_options` based on the number of containers on a workspace
+using `layout_options_rules`. This uses the same threshold-based logic as `layout_rules`:
+when the container count is greater than or equal to a threshold, the highest matching
+threshold's options are used.
+
+Rules **fully replace** the base `layout_options` when they match. If no rule matches, the
+base `layout_options` is used.
+
+### Configuration
+
+```json
+{
+  "monitors": [
+    {
+      "workspaces": [
+        {
+          "name": "main",
+          "layout": "VerticalStack",
+          "layout_options": {
+            "column_ratios": [0.6],
+            "row_ratios": [0.4]
+          },
+          "layout_options_rules": {
+            "3": { "column_ratios": [0.55] },
+            "5": { "column_ratios": [0.3, 0.3, 0.3], "row_ratios": [0.5] }
+          }
+        }
+      ]
+    }
+  ]
+}
+```
+
+In the example above:
+
+| Container Count | Effective `layout_options` |
+|-----------------|---------------------------|
+| 1-2 | Base: `column_ratios: [0.6]`, `row_ratios: [0.4]` |
+| 3-4 | Rule "3": `column_ratios: [0.55]` (no row_ratios, no scrolling, no grid) |
+| 5+ | Rule "5": `column_ratios: [0.3, 0.3, 0.3]`, `row_ratios: [0.5]` |
+
+Rules can include any field that `layout_options` supports: `column_ratios`, `row_ratios`,
+`scrolling`, and `grid`. When a rule matches, it completely replaces the base options. Fields
+not specified in the matching rule default to their standard defaults (not the base
+`layout_options` values).
+
+### Example: Scrolling Layout with Dynamic Columns
+
+```json
+{
+  "layout": "Scrolling",
+  "layout_options": {
+    "scrolling": { "columns": 2 }
+  },
+  "layout_options_rules": {
+    "4": { "scrolling": { "columns": 3 } },
+    "7": { "scrolling": { "columns": 4 } }
+  }
+}
+```
+
+This increases the visible scrolling columns as more windows are added.
+
+## Layout Defaults
+
+You can define global per-layout default `layout_options` and `layout_options_rules` using
+the top-level `layout_defaults` setting. This avoids repeating the same configuration across
+every workspace that uses the same layout.
+
+### Configuration
+
+```json
+{
+  "layout_defaults": {
+    "VerticalStack": {
+      "layout_options": { "column_ratios": [0.7] },
+      "layout_options_rules": {
+        "2": { "column_ratios": [0.7] },
+        "3": { "column_ratios": [0.55] },
+        "5": { "column_ratios": [0.4] }
+      }
+    },
+    "Columns": {
+      "layout_options": { "column_ratios": [0.3, 0.4] },
+      "layout_options_rules": {
+        "4": { "column_ratios": [0.2, 0.3, 0.3] }
+      }
+    },
+    "HorizontalStack": {
+      "layout_options": { "row_ratios": [0.6] }
+    }
+  },
+  "monitors": [
+    {
+      "workspaces": [
+        {
+          "name": "main",
+          "layout": "VerticalStack"
+        }
+      ]
+    }
+  ]
+}
+```
+
+In this example, every workspace using `VerticalStack`, `Columns`, or `HorizontalStack`
+automatically gets the global `layout_options` and `layout_options_rules` without needing
+to specify them per-workspace. Note that `VerticalStack` only has 2 columns (main + stack),
+so only a single `column_ratios` value is meaningful, while `Columns` distributes windows
+across multiple columns where additional ratios control each column's width.
+
+### Resolution Cascade
+
+Global defaults act as a fallback. If a workspace defines **either** `layout_options` or
+`layout_options_rules`, it **completely replaces** all global `layout_defaults` for that
+layout. Global defaults are only used when the workspace has **neither** setting.
+
+Within the effective source (workspace or global):
+1. Try threshold match from the rules (highest matching threshold wins)
+2. If a rule matches → use it (full replacement of base options)
+3. Otherwise → use the base `layout_options`
+
+### Override Examples
+
+| Workspace Config | Global Config | Effective Behavior |
+|------------------|---------------|--------------------|
+| No `layout_options`, no rules | `layout_defaults` has both | Uses global base + global rules |
+| Has `layout_options` only | `layout_defaults` has both | Workspace base only (all globals ignored) |
+| Has `layout_options_rules` only | `layout_defaults` has both | Workspace rules only (all globals ignored) |
+| Has both | `layout_defaults` has both | All workspace (all globals ignored) |
+
+This "complete replacement" semantic means you never get a mix of workspace and global
+settings for the same layout. If you override anything at the workspace level, you take
+full control of that layout's options for that workspace.
+
 ## Progressive Ratio Behavior

 Ratios are applied progressively as windows are added. For example, with `row_ratios: [0.3, 0.5]` in a VerticalStack:
--- a/komorebi-layouts/src/default_layout.rs
+++ b/komorebi-layouts/src/default_layout.rs
@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use clap::ValueEnum;
 use serde::Deserialize;
 use serde::Serialize;
@@ -54,7 +56,7 @@ pub fn validate_ratios(ratios: &[f32]) -> [Option<f32>; MAX_RATIOS] {
 }

 #[derive(
-    Clone, Copy, Debug, Serialize, Deserialize, Eq, PartialEq, Display, EnumString, ValueEnum,
+    Clone, Copy, Debug, Serialize, Deserialize, Eq, PartialEq, Hash, Display, EnumString, ValueEnum,
 )]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 /// A predefined komorebi layout
@@ -250,6 +252,21 @@ pub struct GridLayoutOptions {
    pub rows: usize,
 }

+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+/// Per-layout default options entry for the `layout_defaults` global setting.
+/// Contains both base layout options and threshold-based layout options rules.
+pub struct LayoutDefaultEntry {
+    /// Default layout options for this layout
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub layout_options: Option<LayoutOptions>,
+    /// Threshold-based layout options rules in the format of threshold => options.
+    /// When container count >= threshold, the highest matching threshold's options
+    /// fully replace the base `layout_options`.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub layout_options_rules: Option<HashMap<usize, LayoutOptions>>,
+}
+
 impl DefaultLayout {
    pub fn leftmost_index(&self, len: usize) -> usize {
        match self {
@@ -420,370 +437,5 @@ impl DefaultLayout {
 }

 #[cfg(test)]
-mod tests {
-    use super::*;
-
-    // Helper to create LayoutOptions with column ratios
-    fn layout_options_with_column_ratios(ratios: &[f32]) -> LayoutOptions {
-        let mut arr = [None; MAX_RATIOS];
-        for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
-            arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: Some(arr),
-            row_ratios: None,
-        }
-    }
-
-    // Helper to create LayoutOptions with row ratios
-    fn layout_options_with_row_ratios(ratios: &[f32]) -> LayoutOptions {
-        let mut arr = [None; MAX_RATIOS];
-        for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
-            arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: None,
-            row_ratios: Some(arr),
-        }
-    }
-
-    // Helper to create LayoutOptions with both column and row ratios
-    fn layout_options_with_ratios(column_ratios: &[f32], row_ratios: &[f32]) -> LayoutOptions {
-        let mut col_arr = [None; MAX_RATIOS];
-        for (i, &r) in column_ratios.iter().take(MAX_RATIOS).enumerate() {
-            col_arr[i] = Some(r);
-        }
-        let mut row_arr = [None; MAX_RATIOS];
-        for (i, &r) in row_ratios.iter().take(MAX_RATIOS).enumerate() {
-            row_arr[i] = Some(r);
-        }
-        LayoutOptions {
-            scrolling: None,
-            grid: None,
-            column_ratios: Some(col_arr),
-            row_ratios: Some(row_arr),
-        }
-    }
-
-    mod deserialize_ratios_tests {
-        use super::*;
-
-        #[test]
-        fn test_deserialize_valid_ratios() {
-            let json = r#"{"column_ratios": [0.3, 0.4, 0.2]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.3));
-            assert_eq!(ratios[1], Some(0.4));
-            assert_eq!(ratios[2], Some(0.2));
-            assert_eq!(ratios[3], None);
-            assert_eq!(ratios[4], None);
-        }
-
-        #[test]
-        fn test_deserialize_clamps_values_to_min() {
-            // Values below MIN_RATIO should be clamped
-            let json = r#"{"column_ratios": [0.05]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(MIN_RATIO)); // Clamped to 0.1
-        }
-
-        #[test]
-        fn test_deserialize_clamps_values_to_max() {
-            // Values above MAX_RATIO should be clamped
-            let json = r#"{"column_ratios": [0.95]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            // 0.9 is the max, so it should be clamped
-            assert!(ratios[0].unwrap() <= MAX_RATIO);
-        }
-
-        #[test]
-        fn test_deserialize_truncates_when_sum_exceeds_one() {
-            // Sum of ratios should not reach 1.0
-            // [0.5, 0.4] = 0.9, then 0.3 would make it 1.2, so it should be truncated
-            let json = r#"{"column_ratios": [0.5, 0.4, 0.3]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.5));
-            assert_eq!(ratios[1], Some(0.4));
-            // Third ratio should be truncated because 0.5 + 0.4 + 0.3 >= 1.0
-            assert_eq!(ratios[2], None);
-        }
-
-        #[test]
-        fn test_deserialize_truncates_at_max_ratios() {
-            // More than MAX_RATIOS values should be truncated
-            let json = r#"{"column_ratios": [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            // Only MAX_RATIOS (5) values should be stored
-            for item in ratios.iter().take(MAX_RATIOS) {
-                assert_eq!(*item, Some(0.1));
-            }
-        }
-
-        #[test]
-        fn test_deserialize_empty_array() {
-            let json = r#"{"column_ratios": []}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.column_ratios.unwrap();
-            for item in ratios.iter().take(MAX_RATIOS) {
-                assert_eq!(*item, None);
-            }
-        }
-
-        #[test]
-        fn test_deserialize_null() {
-            let json = r#"{"column_ratios": null}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-            assert!(opts.column_ratios.is_none());
-        }
-
-        #[test]
-        fn test_deserialize_row_ratios() {
-            let json = r#"{"row_ratios": [0.3, 0.5]}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            let ratios = opts.row_ratios.unwrap();
-            assert_eq!(ratios[0], Some(0.3));
-            assert_eq!(ratios[1], Some(0.5));
-            assert_eq!(ratios[2], None);
-        }
-    }
-
-    mod serialize_ratios_tests {
-        use super::*;
-
-        #[test]
-        fn test_serialize_ratios_compact() {
-            let opts = layout_options_with_column_ratios(&[0.3, 0.4]);
-            let json = serde_json::to_string(&opts).unwrap();
-
-            // Should serialize ratios as compact array without trailing nulls in the ratios array
-            assert!(json.contains("0.3") && json.contains("0.4"));
-        }
-
-        #[test]
-        fn test_serialize_none_ratios() {
-            let opts = LayoutOptions {
-                scrolling: None,
-                grid: None,
-                column_ratios: None,
-                row_ratios: None,
-            };
-            let json = serde_json::to_string(&opts).unwrap();
-
-            // None values should serialize as null or be omitted
-            assert!(!json.contains("["));
-        }
-
-        #[test]
-        fn test_roundtrip_serialization() {
-            let original = layout_options_with_column_ratios(&[0.3, 0.4, 0.2]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.column_ratios, deserialized.column_ratios);
-        }
-
-        #[test]
-        fn test_serialize_row_ratios() {
-            let opts = layout_options_with_row_ratios(&[0.3, 0.5]);
-            let json = serde_json::to_string(&opts).unwrap();
-
-            assert!(json.contains("row_ratios"));
-            assert!(json.contains("0.3") && json.contains("0.5"));
-        }
-
-        #[test]
-        fn test_roundtrip_row_ratios() {
-            let original = layout_options_with_row_ratios(&[0.4, 0.3]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.row_ratios, deserialized.row_ratios);
-            assert!(original.column_ratios.is_none());
-        }
-
-        #[test]
-        fn test_roundtrip_both_ratios() {
-            let original = layout_options_with_ratios(&[0.3, 0.4], &[0.5, 0.3]);
-            let json = serde_json::to_string(&original).unwrap();
-            let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
-
-            assert_eq!(original.column_ratios, deserialized.column_ratios);
-            assert_eq!(original.row_ratios, deserialized.row_ratios);
-        }
-    }
-
-    mod ratio_constants_tests {
-        use super::*;
-
-        #[test]
-        fn test_constants_valid_ranges() {
-            const {
-                assert!(MIN_RATIO > 0.0);
-                assert!(MIN_RATIO < MAX_RATIO);
-                assert!(MAX_RATIO < 1.0);
-                assert!(DEFAULT_RATIO >= MIN_RATIO && DEFAULT_RATIO <= MAX_RATIO);
-                assert!(
-                    DEFAULT_SECONDARY_RATIO >= MIN_RATIO && DEFAULT_SECONDARY_RATIO <= MAX_RATIO
-                );
-                assert!(MAX_RATIOS >= 1);
-            }
-        }
-
-        #[test]
-        fn test_default_ratio_is_half() {
-            assert_eq!(DEFAULT_RATIO, 0.5);
-        }
-
-        #[test]
-        fn test_max_ratios_is_five() {
-            assert_eq!(MAX_RATIOS, 5);
-        }
-    }
-
-    mod layout_options_tests {
-        use super::*;
-
-        #[test]
-        fn test_layout_options_default_values() {
-            let json = r#"{}"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            assert!(opts.scrolling.is_none());
-            assert!(opts.grid.is_none());
-            assert!(opts.column_ratios.is_none());
-            assert!(opts.row_ratios.is_none());
-        }
-
-        #[test]
-        fn test_layout_options_with_all_fields() {
-            let json = r#"{
-                "scrolling": {"columns": 3},
-                "grid": {"rows": 2},
-                "column_ratios": [0.3, 0.4],
-                "row_ratios": [0.5]
-            }"#;
-            let opts: LayoutOptions = serde_json::from_str(json).unwrap();
-
-            assert!(opts.scrolling.is_some());
-            assert_eq!(opts.scrolling.unwrap().columns, 3);
-            assert!(opts.grid.is_some());
-            assert_eq!(opts.grid.unwrap().rows, 2);
-            assert!(opts.column_ratios.is_some());
-            assert!(opts.row_ratios.is_some());
-        }
-    }
-
-    mod default_layout_tests {
-        use super::*;
-
-        #[test]
-        fn test_cycle_next_covers_all_layouts() {
-            let start = DefaultLayout::BSP;
-            let mut current = start;
-            let mut visited = vec![current];
-
-            loop {
-                current = current.cycle_next();
-                if current == start {
-                    break;
-                }
-                assert!(
-                    !visited.contains(&current),
-                    "Cycle contains duplicate: {:?}",
-                    current
-                );
-                visited.push(current);
-            }
-
-            // Should have visited all layouts
-            assert_eq!(visited.len(), 9); // 9 layouts total
-        }
-
-        #[test]
-        fn test_cycle_previous_is_inverse_of_next() {
-            // Note: cycle_previous has some inconsistencies in the current implementation
-            // This test documents the expected behavior for most layouts
-            let layouts_with_correct_inverse = [
-                DefaultLayout::Columns,
-                DefaultLayout::Rows,
-                DefaultLayout::VerticalStack,
-                DefaultLayout::HorizontalStack,
-                DefaultLayout::UltrawideVerticalStack,
-                DefaultLayout::Grid,
-                DefaultLayout::RightMainVerticalStack,
-            ];
-
-            for layout in layouts_with_correct_inverse {
-                let next = layout.cycle_next();
-                assert_eq!(
-                    next.cycle_previous(),
-                    layout,
-                    "cycle_previous should be inverse of cycle_next for {:?}",
-                    layout
-                );
-            }
-        }
-
-        #[test]
-        fn test_leftmost_index_standard_layouts() {
-            assert_eq!(DefaultLayout::BSP.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Columns.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Rows.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::VerticalStack.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::HorizontalStack.leftmost_index(5), 0);
-            assert_eq!(DefaultLayout::Grid.leftmost_index(5), 0);
-        }
-
-        #[test]
-        fn test_leftmost_index_ultrawide() {
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(1), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(2), 1);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(5), 1);
-        }
-
-        #[test]
-        fn test_leftmost_index_right_main() {
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(1), 0);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(2), 1);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(5), 1);
-        }
-
-        #[test]
-        fn test_rightmost_index_standard_layouts() {
-            assert_eq!(DefaultLayout::BSP.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::Columns.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::Rows.rightmost_index(5), 4);
-            assert_eq!(DefaultLayout::VerticalStack.rightmost_index(5), 4);
-        }
-
-        #[test]
-        fn test_rightmost_index_right_main() {
-            assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(1), 0);
-            assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(5), 0);
-        }
-
-        #[test]
-        fn test_rightmost_index_ultrawide() {
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(1), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(2), 0);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(3), 2);
-            assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(5), 4);
-        }
-    }
-}
+#[path = "default_layout_tests.rs"]
+mod tests;
--- a/komorebi-layouts/src/default_layout_tests.rs
+++ b/komorebi-layouts/src/default_layout_tests.rs
@@ -0,0 +1,954 @@
+use super::*;
+
+// Helper to create LayoutOptions with column ratios
+fn layout_options_with_column_ratios(ratios: &[f32]) -> LayoutOptions {
+    let mut arr = [None; MAX_RATIOS];
+    for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
+        arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: Some(arr),
+        row_ratios: None,
+    }
+}
+
+// Helper to create LayoutOptions with row ratios
+fn layout_options_with_row_ratios(ratios: &[f32]) -> LayoutOptions {
+    let mut arr = [None; MAX_RATIOS];
+    for (i, &r) in ratios.iter().take(MAX_RATIOS).enumerate() {
+        arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: None,
+        row_ratios: Some(arr),
+    }
+}
+
+// Helper to create LayoutOptions with both column and row ratios
+fn layout_options_with_ratios(column_ratios: &[f32], row_ratios: &[f32]) -> LayoutOptions {
+    let mut col_arr = [None; MAX_RATIOS];
+    for (i, &r) in column_ratios.iter().take(MAX_RATIOS).enumerate() {
+        col_arr[i] = Some(r);
+    }
+    let mut row_arr = [None; MAX_RATIOS];
+    for (i, &r) in row_ratios.iter().take(MAX_RATIOS).enumerate() {
+        row_arr[i] = Some(r);
+    }
+    LayoutOptions {
+        scrolling: None,
+        grid: None,
+        column_ratios: Some(col_arr),
+        row_ratios: Some(row_arr),
+    }
+}
+
+mod deserialize_ratios_tests {
+    use super::*;
+
+    #[test]
+    fn test_deserialize_valid_ratios() {
+        let json = r#"{"column_ratios": [0.3, 0.4, 0.2]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.3));
+        assert_eq!(ratios[1], Some(0.4));
+        assert_eq!(ratios[2], Some(0.2));
+        assert_eq!(ratios[3], None);
+        assert_eq!(ratios[4], None);
+    }
+
+    #[test]
+    fn test_deserialize_clamps_values_to_min() {
+        // Values below MIN_RATIO should be clamped
+        let json = r#"{"column_ratios": [0.05]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(MIN_RATIO)); // Clamped to 0.1
+    }
+
+    #[test]
+    fn test_deserialize_clamps_values_to_max() {
+        // Values above MAX_RATIO should be clamped
+        let json = r#"{"column_ratios": [0.95]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        // 0.9 is the max, so it should be clamped
+        assert!(ratios[0].unwrap() <= MAX_RATIO);
+    }
+
+    #[test]
+    fn test_deserialize_truncates_when_sum_exceeds_one() {
+        // Sum of ratios should not reach 1.0
+        // [0.5, 0.4] = 0.9, then 0.3 would make it 1.2, so it should be truncated
+        let json = r#"{"column_ratios": [0.5, 0.4, 0.3]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.5));
+        assert_eq!(ratios[1], Some(0.4));
+        // Third ratio should be truncated because 0.5 + 0.4 + 0.3 >= 1.0
+        assert_eq!(ratios[2], None);
+    }
+
+    #[test]
+    fn test_deserialize_truncates_at_max_ratios() {
+        // More than MAX_RATIOS values should be truncated
+        let json = r#"{"column_ratios": [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        // Only MAX_RATIOS (5) values should be stored
+        for item in ratios.iter().take(MAX_RATIOS) {
+            assert_eq!(*item, Some(0.1));
+        }
+    }
+
+    #[test]
+    fn test_deserialize_empty_array() {
+        let json = r#"{"column_ratios": []}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.column_ratios.unwrap();
+        for item in ratios.iter().take(MAX_RATIOS) {
+            assert_eq!(*item, None);
+        }
+    }
+
+    #[test]
+    fn test_deserialize_null() {
+        let json = r#"{"column_ratios": null}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        assert!(opts.column_ratios.is_none());
+    }
+
+    #[test]
+    fn test_deserialize_row_ratios() {
+        let json = r#"{"row_ratios": [0.3, 0.5]}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        let ratios = opts.row_ratios.unwrap();
+        assert_eq!(ratios[0], Some(0.3));
+        assert_eq!(ratios[1], Some(0.5));
+        assert_eq!(ratios[2], None);
+    }
+}
+
+mod serialize_ratios_tests {
+    use super::*;
+
+    #[test]
+    fn test_serialize_ratios_compact() {
+        let opts = layout_options_with_column_ratios(&[0.3, 0.4]);
+        let json = serde_json::to_string(&opts).unwrap();
+
+        // Should serialize ratios as compact array without trailing nulls in the ratios array
+        assert!(json.contains("0.3") && json.contains("0.4"));
+    }
+
+    #[test]
+    fn test_serialize_none_ratios() {
+        let opts = LayoutOptions {
+            scrolling: None,
+            grid: None,
+            column_ratios: None,
+            row_ratios: None,
+        };
+        let json = serde_json::to_string(&opts).unwrap();
+
+        // None values should serialize as null or be omitted
+        assert!(!json.contains("["));
+    }
+
+    #[test]
+    fn test_roundtrip_serialization() {
+        let original = layout_options_with_column_ratios(&[0.3, 0.4, 0.2]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.column_ratios, deserialized.column_ratios);
+    }
+
+    #[test]
+    fn test_serialize_row_ratios() {
+        let opts = layout_options_with_row_ratios(&[0.3, 0.5]);
+        let json = serde_json::to_string(&opts).unwrap();
+
+        assert!(json.contains("row_ratios"));
+        assert!(json.contains("0.3") && json.contains("0.5"));
+    }
+
+    #[test]
+    fn test_roundtrip_row_ratios() {
+        let original = layout_options_with_row_ratios(&[0.4, 0.3]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.row_ratios, deserialized.row_ratios);
+        assert!(original.column_ratios.is_none());
+    }
+
+    #[test]
+    fn test_roundtrip_both_ratios() {
+        let original = layout_options_with_ratios(&[0.3, 0.4], &[0.5, 0.3]);
+        let json = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutOptions = serde_json::from_str(&json).unwrap();
+
+        assert_eq!(original.column_ratios, deserialized.column_ratios);
+        assert_eq!(original.row_ratios, deserialized.row_ratios);
+    }
+}
+
+mod ratio_constants_tests {
+    use super::*;
+
+    #[test]
+    fn test_constants_valid_ranges() {
+        const {
+            assert!(MIN_RATIO > 0.0);
+            assert!(MIN_RATIO < MAX_RATIO);
+            assert!(MAX_RATIO < 1.0);
+            assert!(DEFAULT_RATIO >= MIN_RATIO && DEFAULT_RATIO <= MAX_RATIO);
+            assert!(DEFAULT_SECONDARY_RATIO >= MIN_RATIO && DEFAULT_SECONDARY_RATIO <= MAX_RATIO);
+            assert!(MAX_RATIOS >= 1);
+        }
+    }
+
+    #[test]
+    fn test_default_ratio_is_half() {
+        assert_eq!(DEFAULT_RATIO, 0.5);
+    }
+
+    #[test]
+    fn test_max_ratios_is_five() {
+        assert_eq!(MAX_RATIOS, 5);
+    }
+}
+
+mod layout_options_tests {
+    use super::*;
+
+    #[test]
+    fn test_layout_options_default_values() {
+        let json = r#"{}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        assert!(opts.scrolling.is_none());
+        assert!(opts.grid.is_none());
+        assert!(opts.column_ratios.is_none());
+        assert!(opts.row_ratios.is_none());
+    }
+
+    #[test]
+    fn test_layout_options_with_all_fields() {
+        let json = r#"{
+            "scrolling": {"columns": 3},
+            "grid": {"rows": 2},
+            "column_ratios": [0.3, 0.4],
+            "row_ratios": [0.5]
+        }"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+
+        assert!(opts.scrolling.is_some());
+        assert_eq!(opts.scrolling.unwrap().columns, 3);
+        assert!(opts.grid.is_some());
+        assert_eq!(opts.grid.unwrap().rows, 2);
+        assert!(opts.column_ratios.is_some());
+        assert!(opts.row_ratios.is_some());
+    }
+}
+
+mod default_layout_tests {
+    use super::*;
+
+    #[test]
+    fn test_cycle_next_covers_all_layouts() {
+        let start = DefaultLayout::BSP;
+        let mut current = start;
+        let mut visited = vec![current];
+
+        loop {
+            current = current.cycle_next();
+            if current == start {
+                break;
+            }
+            assert!(
+                !visited.contains(&current),
+                "Cycle contains duplicate: {:?}",
+                current
+            );
+            visited.push(current);
+        }
+
+        // Should have visited all layouts
+        assert_eq!(visited.len(), 9); // 9 layouts total
+    }
+
+    #[test]
+    fn test_cycle_previous_is_inverse_of_next() {
+        // Note: cycle_previous has some inconsistencies in the current implementation
+        // This test documents the expected behavior for most layouts
+        let layouts_with_correct_inverse = [
+            DefaultLayout::Columns,
+            DefaultLayout::Rows,
+            DefaultLayout::VerticalStack,
+            DefaultLayout::HorizontalStack,
+            DefaultLayout::UltrawideVerticalStack,
+            DefaultLayout::Grid,
+            DefaultLayout::RightMainVerticalStack,
+        ];
+
+        for layout in layouts_with_correct_inverse {
+            let next = layout.cycle_next();
+            assert_eq!(
+                next.cycle_previous(),
+                layout,
+                "cycle_previous should be inverse of cycle_next for {:?}",
+                layout
+            );
+        }
+    }
+
+    #[test]
+    fn test_leftmost_index_standard_layouts() {
+        assert_eq!(DefaultLayout::BSP.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Columns.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Rows.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::VerticalStack.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::HorizontalStack.leftmost_index(5), 0);
+        assert_eq!(DefaultLayout::Grid.leftmost_index(5), 0);
+    }
+
+    #[test]
+    fn test_leftmost_index_ultrawide() {
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(1), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(2), 1);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.leftmost_index(5), 1);
+    }
+
+    #[test]
+    fn test_leftmost_index_right_main() {
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(1), 0);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(2), 1);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.leftmost_index(5), 1);
+    }
+
+    #[test]
+    fn test_rightmost_index_standard_layouts() {
+        assert_eq!(DefaultLayout::BSP.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::Columns.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::Rows.rightmost_index(5), 4);
+        assert_eq!(DefaultLayout::VerticalStack.rightmost_index(5), 4);
+    }
+
+    #[test]
+    fn test_rightmost_index_right_main() {
+        assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(1), 0);
+        assert_eq!(DefaultLayout::RightMainVerticalStack.rightmost_index(5), 0);
+    }
+
+    #[test]
+    fn test_rightmost_index_ultrawide() {
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(1), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(2), 0);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(3), 2);
+        assert_eq!(DefaultLayout::UltrawideVerticalStack.rightmost_index(5), 4);
+    }
+}
+
+mod layout_options_rules_tests {
+    use super::*;
+
+    #[test]
+    fn test_hashmap_deserialization_ratios_only() {
+        // layout_options_rules entries with only ratios
+        // Note: ratios must sum to < 1.0 to avoid truncation by validate_ratios
+        let json = r#"{
+            "2": {"column_ratios": [0.7]},
+            "3": {"column_ratios": [0.55]},
+            "5": {"column_ratios": [0.3, 0.3, 0.3]}
+        }"#;
+        let rules: std::collections::HashMap<usize, LayoutOptions> =
+            serde_json::from_str(json).unwrap();
+        assert_eq!(rules.len(), 3);
+        assert_eq!(rules[&2].column_ratios.unwrap()[0], Some(0.7));
+        assert_eq!(rules[&3].column_ratios.unwrap()[0], Some(0.55));
+        let r5 = rules[&5].column_ratios.unwrap();
+        assert_eq!(r5[0], Some(0.3));
+        assert_eq!(r5[1], Some(0.3));
+        assert_eq!(r5[2], Some(0.3));
+        // No scrolling/grid in these entries
+        assert!(rules[&2].scrolling.is_none());
+        assert!(rules[&2].grid.is_none());
+    }
+
+    #[test]
+    fn test_hashmap_deserialization_full_options() {
+        // layout_options_rules entries with full options including scrolling/grid
+        let json = r#"{
+            "2": {"column_ratios": [0.7], "scrolling": {"columns": 3}},
+            "5": {"column_ratios": [0.3, 0.3, 0.3], "grid": {"rows": 2}}
+        }"#;
+        let rules: std::collections::HashMap<usize, LayoutOptions> =
+            serde_json::from_str(json).unwrap();
+        assert_eq!(rules.len(), 2);
+        assert_eq!(rules[&2].scrolling.unwrap().columns, 3);
+        assert!(rules[&2].grid.is_none());
+        assert!(rules[&5].scrolling.is_none());
+        assert_eq!(rules[&5].grid.unwrap().rows, 2);
+    }
+
+    #[test]
+    fn test_rule_entry_with_all_fields() {
+        let json = r#"{
+            "column_ratios": [0.6, 0.3],
+            "scrolling": {"columns": 4, "center_focused_column": true},
+            "grid": {"rows": 2},
+            "row_ratios": [0.5]
+        }"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        let col = opts.column_ratios.unwrap();
+        assert_eq!(col[0], Some(0.6));
+        assert_eq!(col[1], Some(0.3));
+        let row = opts.row_ratios.unwrap();
+        assert_eq!(row[0], Some(0.5));
+        assert_eq!(opts.scrolling.unwrap().columns, 4);
+        assert_eq!(opts.scrolling.unwrap().center_focused_column, Some(true));
+        assert_eq!(opts.grid.unwrap().rows, 2);
+    }
+
+    #[test]
+    fn test_rule_entry_empty_object_gives_defaults() {
+        let json = r#"{}"#;
+        let opts: LayoutOptions = serde_json::from_str(json).unwrap();
+        assert!(opts.column_ratios.is_none());
+        assert!(opts.row_ratios.is_none());
+        assert!(opts.scrolling.is_none());
+        assert!(opts.grid.is_none());
+    }
+}
+
+mod layout_default_entry_tests {
+    use super::*;
+    use std::collections::HashMap;
+
+    #[test]
+    fn test_default_layout_as_hashmap_key() {
+        let mut map: HashMap<DefaultLayout, &str> = HashMap::new();
+        map.insert(DefaultLayout::BSP, "bsp");
+        map.insert(DefaultLayout::VerticalStack, "vstack");
+        map.insert(DefaultLayout::Columns, "cols");
+
+        assert_eq!(map.len(), 3);
+        assert_eq!(map[&DefaultLayout::BSP], "bsp");
+        assert_eq!(map[&DefaultLayout::VerticalStack], "vstack");
+        assert_eq!(map[&DefaultLayout::Columns], "cols");
+    }
+
+    #[test]
+    fn test_default_layout_hash_consistency() {
+        // Same variant inserted twice should overwrite
+        let mut map: HashMap<DefaultLayout, i32> = HashMap::new();
+        map.insert(DefaultLayout::Grid, 1);
+        map.insert(DefaultLayout::Grid, 2);
+        assert_eq!(map.len(), 1);
+        assert_eq!(map[&DefaultLayout::Grid], 2);
+    }
+
+    #[test]
+    fn test_layout_default_entry_deserialize_full() {
+        let json = r#"{
+            "layout_options": {"column_ratios": [0.7]},
+            "layout_options_rules": {
+                "2": {"column_ratios": [0.7]},
+                "3": {"column_ratios": [0.55]},
+                "5": {"column_ratios": [0.3, 0.3, 0.3]}
+            }
+        }"#;
+        let entry: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+
+        let base = entry.layout_options.unwrap();
+        assert_eq!(base.column_ratios.unwrap()[0], Some(0.7));
+
+        let rules = entry.layout_options_rules.unwrap();
+        assert_eq!(rules.len(), 3);
+        assert_eq!(rules[&2].column_ratios.unwrap()[0], Some(0.7));
+        assert_eq!(rules[&3].column_ratios.unwrap()[0], Some(0.55));
+        let r5 = rules[&5].column_ratios.unwrap();
+        assert_eq!(r5[0], Some(0.3));
+        assert_eq!(r5[1], Some(0.3));
+        assert_eq!(r5[2], Some(0.3));
+    }
+
+    #[test]
+    fn test_layout_default_entry_deserialize_only_base() {
+        let json = r#"{
+            "layout_options": {"column_ratios": [0.6]}
+        }"#;
+        let entry: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+
+        assert!(entry.layout_options.is_some());
+        assert_eq!(
+            entry.layout_options.unwrap().column_ratios.unwrap()[0],
+            Some(0.6)
+        );
+        assert!(entry.layout_options_rules.is_none());
+    }
+
+    #[test]
+    fn test_layout_default_entry_deserialize_only_rules() {
+        let json = r#"{
+            "layout_options_rules": {
+                "3": {"column_ratios": [0.4]}
+            }
+        }"#;
+        let entry: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+
+        assert!(entry.layout_options.is_none());
+        let rules = entry.layout_options_rules.unwrap();
+        assert_eq!(rules.len(), 1);
+        assert_eq!(rules[&3].column_ratios.unwrap()[0], Some(0.4));
+    }
+
+    #[test]
+    fn test_layout_default_entry_deserialize_empty() {
+        let json = r#"{}"#;
+        let entry: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+        assert!(entry.layout_options.is_none());
+        assert!(entry.layout_options_rules.is_none());
+    }
+
+    #[test]
+    fn test_layout_default_entry_roundtrip() {
+        let json = r#"{
+            "layout_options": {"column_ratios": [0.7]},
+            "layout_options_rules": {
+                "2": {"column_ratios": [0.6]},
+                "5": {"column_ratios": [0.3, 0.3, 0.3]}
+            }
+        }"#;
+        let original: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+        let serialized = serde_json::to_string(&original).unwrap();
+        let deserialized: LayoutDefaultEntry = serde_json::from_str(&serialized).unwrap();
+
+        assert_eq!(
+            original.layout_options.unwrap().column_ratios,
+            deserialized.layout_options.unwrap().column_ratios
+        );
+        let orig_rules = original.layout_options_rules.unwrap();
+        let deser_rules = deserialized.layout_options_rules.unwrap();
+        assert_eq!(orig_rules.len(), deser_rules.len());
+        for (key, orig_opts) in &orig_rules {
+            let deser_opts = &deser_rules[key];
+            assert_eq!(orig_opts.column_ratios, deser_opts.column_ratios);
+        }
+    }
+
+    #[test]
+    fn test_layout_defaults_full_config_deserialize() {
+        // Simulate the top-level layout_defaults field
+        let json = r#"{
+            "VerticalStack": {
+                "layout_options": {"column_ratios": [0.7]},
+                "layout_options_rules": {
+                    "2": {"column_ratios": [0.7]},
+                    "3": {"column_ratios": [0.55]}
+                }
+            },
+            "HorizontalStack": {
+                "layout_options": {"column_ratios": [0.6]}
+            },
+            "Columns": {
+                "layout_options_rules": {
+                    "4": {"column_ratios": [0.3, 0.3, 0.3]}
+                }
+            }
+        }"#;
+        let defaults: HashMap<DefaultLayout, LayoutDefaultEntry> =
+            serde_json::from_str(json).unwrap();
+
+        assert_eq!(defaults.len(), 3);
+
+        // VerticalStack: has both base and rules
+        let vs = &defaults[&DefaultLayout::VerticalStack];
+        assert!(vs.layout_options.is_some());
+        assert_eq!(vs.layout_options_rules.as_ref().unwrap().len(), 2);
+
+        // HorizontalStack: has only base
+        let hs = &defaults[&DefaultLayout::HorizontalStack];
+        assert!(hs.layout_options.is_some());
+        assert!(hs.layout_options_rules.is_none());
+
+        // Columns: has only rules
+        let cols = &defaults[&DefaultLayout::Columns];
+        assert!(cols.layout_options.is_none());
+        assert_eq!(cols.layout_options_rules.as_ref().unwrap().len(), 1);
+    }
+
+    #[test]
+    fn test_layout_default_entry_with_scrolling_and_grid() {
+        let json = r#"{
+            "layout_options": {
+                "column_ratios": [0.5],
+                "scrolling": {"columns": 3},
+                "grid": {"rows": 2}
+            },
+            "layout_options_rules": {
+                "4": {
+                    "scrolling": {"columns": 5, "center_focused_column": true}
+                }
+            }
+        }"#;
+        let entry: LayoutDefaultEntry = serde_json::from_str(json).unwrap();
+
+        let base = entry.layout_options.unwrap();
+        assert_eq!(base.scrolling.unwrap().columns, 3);
+        assert_eq!(base.grid.unwrap().rows, 2);
+
+        let rules = entry.layout_options_rules.unwrap();
+        let r4 = &rules[&4];
+        assert_eq!(r4.scrolling.unwrap().columns, 5);
+        assert_eq!(r4.scrolling.unwrap().center_focused_column, Some(true));
+        // Rule doesn't inherit base fields - full replacement
+        assert!(r4.column_ratios.is_none());
+        assert!(r4.grid.is_none());
+    }
+
+    #[test]
+    fn test_layout_default_entry_skip_serializing_none() {
+        // When both fields are None, they should not appear in output
+        let entry = LayoutDefaultEntry {
+            layout_options: None,
+            layout_options_rules: None,
+        };
+        let json = serde_json::to_string(&entry).unwrap();
+        assert!(!json.contains("layout_options"));
+        assert!(!json.contains("layout_options_rules"));
+        assert_eq!(json, "{}");
+    }
+}
+
+/// Tests for the complete-replacement cascade logic.
+///
+/// This mirrors the resolution algorithm in workspace.rs::update():
+///   - If the workspace defines EITHER layout_options OR layout_options_rules,
+///     it completely replaces the global layout_defaults for this layout.
+///   - Global defaults are only used when the workspace has NEITHER setting.
+///   - Within the effective source (workspace or global):
+///     1. Try threshold match from rules (highest matching threshold wins)
+///     2. If a rule matches -> use it (full replacement of base)
+///     3. Else -> use the base layout_options
+///
+/// Since the actual cascade is in workspace.rs (which has heavy WM dependencies),
+/// we test the pure algorithm here using the same data structures.
+mod cascade_resolution_tests {
+    use super::*;
+
+    /// Simulates the cascade resolution logic from workspace.rs::update().
+    /// This is a pure function equivalent of the inline code in update().
+    fn resolve_effective_options(
+        container_count: usize,
+        workspace_base: Option<LayoutOptions>,
+        workspace_rules: &[(usize, LayoutOptions)], // sorted by threshold ascending
+        global_base: Option<LayoutOptions>,
+        global_rules: &[(usize, LayoutOptions)], // sorted by threshold ascending
+    ) -> Option<LayoutOptions> {
+        let has_workspace_overrides = workspace_base.is_some() || !workspace_rules.is_empty();
+
+        let (effective_base, effective_rules): (Option<LayoutOptions>, &[(usize, LayoutOptions)]) =
+            if has_workspace_overrides {
+                (workspace_base, workspace_rules)
+            } else {
+                (global_base, global_rules)
+            };
+
+        // Try threshold match from effective rules
+        let mut matched = None;
+        for (threshold, opts) in effective_rules {
+            if container_count >= *threshold {
+                matched = Some(*opts);
+            }
+        }
+
+        // If a rule matched, use it (full replacement); otherwise use effective base
+        if matched.is_some() {
+            matched
+        } else {
+            effective_base
+        }
+    }
+
+    fn opts_with_ratio(ratio: f32) -> LayoutOptions {
+        layout_options_with_column_ratios(&[ratio])
+    }
+
+    // --- No overrides ---
+
+    #[test]
+    fn test_no_workspace_no_global_returns_none() {
+        let result = resolve_effective_options(3, None, &[], None, &[]);
+        assert!(result.is_none());
+    }
+
+    // --- Base-only scenarios ---
+
+    #[test]
+    fn test_workspace_base_only() {
+        let ws_base = opts_with_ratio(0.7);
+        let result = resolve_effective_options(3, Some(ws_base), &[], None, &[]);
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    #[test]
+    fn test_global_base_only() {
+        let global_base = opts_with_ratio(0.6);
+        let result = resolve_effective_options(3, None, &[], Some(global_base), &[]);
+        assert_eq!(result.unwrap().column_ratios, global_base.column_ratios);
+    }
+
+    #[test]
+    fn test_workspace_base_overrides_all_globals() {
+        // Workspace has base → globals (both base and rules) are ignored entirely
+        let ws_base = opts_with_ratio(0.7);
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(2, opts_with_ratio(0.5))];
+        let result =
+            resolve_effective_options(3, Some(ws_base), &[], Some(global_base), &global_rules);
+        // Workspace base wins; global rules are NOT used even though they would match
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    // --- Rules-only scenarios ---
+
+    #[test]
+    fn test_global_rules_match() {
+        let global_rules = vec![(2, opts_with_ratio(0.6)), (4, opts_with_ratio(0.5))];
+        // 3 containers: matches threshold 2, not 4
+        let result = resolve_effective_options(3, None, &[], None, &global_rules);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.6));
+    }
+
+    #[test]
+    fn test_global_rules_highest_matching_threshold_wins() {
+        let global_rules = vec![(2, opts_with_ratio(0.6)), (4, opts_with_ratio(0.5))];
+        // 5 containers: matches both thresholds 2 and 4; highest (4) wins
+        let result = resolve_effective_options(5, None, &[], None, &global_rules);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.5));
+    }
+
+    #[test]
+    fn test_global_rules_no_match_falls_through_to_none() {
+        let global_rules = vec![(5, opts_with_ratio(0.5))];
+        // 3 containers: doesn't match threshold 5
+        let result = resolve_effective_options(3, None, &[], None, &global_rules);
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn test_global_rules_no_match_falls_through_to_global_base() {
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(5, opts_with_ratio(0.5))];
+        // 3 containers: doesn't match threshold 5, falls back to global base
+        let result = resolve_effective_options(3, None, &[], Some(global_base), &global_rules);
+        assert_eq!(result.unwrap().column_ratios, global_base.column_ratios);
+    }
+
+    #[test]
+    fn test_workspace_rules_override_global_rules() {
+        let ws_rules = vec![(2, opts_with_ratio(0.8))];
+        let global_rules = vec![(2, opts_with_ratio(0.6))];
+        // Workspace has rules → global rules are ignored entirely
+        let result = resolve_effective_options(3, None, &ws_rules, None, &global_rules);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.8));
+    }
+
+    // --- Complete replacement: workspace having EITHER setting disables ALL globals ---
+
+    #[test]
+    fn test_workspace_rules_disable_global_base() {
+        // Workspace has rules but no base. Global has base.
+        // Since workspace has a setting, globals are completely replaced.
+        let ws_rules = vec![(2, opts_with_ratio(0.8))];
+        let global_base = opts_with_ratio(0.6);
+        // Rule matches → use it. Global base is NOT available as fallback.
+        let result = resolve_effective_options(3, None, &ws_rules, Some(global_base), &[]);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.8));
+    }
+
+    #[test]
+    fn test_workspace_rules_no_match_does_not_fall_to_global_base() {
+        // Workspace has rules (but they don't match). Global has base.
+        // Since workspace has a setting, globals are completely replaced → returns None.
+        let ws_rules = vec![(5, opts_with_ratio(0.8))];
+        let global_base = opts_with_ratio(0.6);
+        let result = resolve_effective_options(3, None, &ws_rules, Some(global_base), &[]);
+        // No workspace base, no rule match, globals ignored → None
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn test_workspace_base_disables_global_rules() {
+        // Workspace has base but no rules. Global has rules.
+        // Since workspace has a setting, globals are completely replaced.
+        let ws_base = opts_with_ratio(0.7);
+        let global_rules = vec![(2, opts_with_ratio(0.5))];
+        // No workspace rules → no rule match → use workspace base. Global rules ignored.
+        let result = resolve_effective_options(3, Some(ws_base), &[], None, &global_rules);
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    #[test]
+    fn test_workspace_base_disables_global_rules_and_base() {
+        // Workspace has base. Global has both rules and base.
+        // Since workspace has a setting, all globals are completely replaced.
+        let ws_base = opts_with_ratio(0.7);
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(2, opts_with_ratio(0.5))];
+        let result =
+            resolve_effective_options(3, Some(ws_base), &[], Some(global_base), &global_rules);
+        // Only workspace base is used; global rules and base are both ignored
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    #[test]
+    fn test_workspace_rules_disable_global_rules_and_base() {
+        // Workspace has rules. Global has both rules and base.
+        // Since workspace has a setting, all globals are completely replaced.
+        let ws_rules = vec![(2, opts_with_ratio(0.8))];
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(2, opts_with_ratio(0.5))];
+        let result =
+            resolve_effective_options(3, None, &ws_rules, Some(global_base), &global_rules);
+        // Workspace rule matches → 0.8. Global base and rules both ignored.
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.8));
+    }
+
+    // --- Full replacement semantics (rule match replaces base) ---
+
+    #[test]
+    fn test_rule_match_is_full_replacement_not_merge() {
+        // When a rule matches, its options FULLY REPLACE the base.
+        // Fields not specified in the rule default to their standard defaults.
+        let ws_base = layout_options_with_ratios(&[0.7], &[0.4]);
+        let rule_opts = layout_options_with_column_ratios(&[0.5]);
+        // rule_opts has column_ratios but no row_ratios
+        let ws_rules = vec![(2, rule_opts)];
+        let result = resolve_effective_options(3, Some(ws_base), &ws_rules, None, &[]);
+        let effective = result.unwrap();
+        // Column ratios come from the rule
+        assert_eq!(effective.column_ratios.unwrap()[0], Some(0.5));
+        // Row ratios are NOT inherited from ws_base - they're None (full replacement)
+        assert!(effective.row_ratios.is_none());
+    }
+
+    // --- Edge cases ---
+
+    #[test]
+    fn test_exact_threshold_match() {
+        let rules = vec![(3, opts_with_ratio(0.6))];
+        let result = resolve_effective_options(3, None, &rules, None, &[]);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.6));
+    }
+
+    #[test]
+    fn test_container_count_one_below_threshold() {
+        let rules = vec![(3, opts_with_ratio(0.6))];
+        let result = resolve_effective_options(2, None, &rules, None, &[]);
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn test_zero_containers() {
+        let ws_base = opts_with_ratio(0.7);
+        let rules = vec![(1, opts_with_ratio(0.5))];
+        let result = resolve_effective_options(0, Some(ws_base), &rules, None, &[]);
+        // 0 containers doesn't match threshold 1 → falls back to workspace base
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    #[test]
+    fn test_many_thresholds_correct_match() {
+        let rules = vec![
+            (1, opts_with_ratio(0.8)),
+            (3, opts_with_ratio(0.6)),
+            (5, opts_with_ratio(0.4)),
+            (8, opts_with_ratio(0.3)),
+        ];
+        // 6 containers: matches 1, 3, 5 but not 8. Highest match is 5.
+        let result = resolve_effective_options(6, None, &rules, None, &[]);
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.4));
+    }
+
+    #[test]
+    fn test_workspace_rules_disable_global_rules_even_if_ws_rules_dont_match() {
+        // Key behavior: if workspace has ANY setting, globals are entirely ignored.
+        // Even if workspace rules don't match, we don't fall back to global rules.
+        let ws_rules = vec![(10, opts_with_ratio(0.8))]; // threshold too high
+        let global_rules = vec![(2, opts_with_ratio(0.5))]; // would match
+        let result = resolve_effective_options(3, None, &ws_rules, None, &global_rules);
+        // Workspace has rules → all globals ignored. WS rules don't match → None.
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn test_all_four_sources_present_rules_match() {
+        // All four sources present: workspace base, workspace rules, global base, global rules
+        let ws_base = opts_with_ratio(0.7);
+        let ws_rules = vec![(2, opts_with_ratio(0.8))];
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(2, opts_with_ratio(0.5))];
+        let result = resolve_effective_options(
+            3,
+            Some(ws_base),
+            &ws_rules,
+            Some(global_base),
+            &global_rules,
+        );
+        // Workspace has settings → uses workspace only. Rule matches → 0.8
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.8));
+    }
+
+    #[test]
+    fn test_all_four_sources_present_rules_no_match() {
+        // All four sources present, but workspace rules don't match
+        let ws_base = opts_with_ratio(0.7);
+        let ws_rules = vec![(10, opts_with_ratio(0.8))]; // threshold too high
+        let global_base = opts_with_ratio(0.6);
+        let global_rules = vec![(10, opts_with_ratio(0.5))]; // also too high
+        let result = resolve_effective_options(
+            3,
+            Some(ws_base),
+            &ws_rules,
+            Some(global_base),
+            &global_rules,
+        );
+        // Workspace has settings → uses workspace only. No rule match → workspace base 0.7
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+
+    // --- Workspace with both base and rules ---
+
+    #[test]
+    fn test_workspace_both_rule_matches() {
+        let ws_base = opts_with_ratio(0.7);
+        let ws_rules = vec![(2, opts_with_ratio(0.5))];
+        let result = resolve_effective_options(3, Some(ws_base), &ws_rules, None, &[]);
+        // Rule matches → use rule (full replacement), not ws_base
+        assert_eq!(result.unwrap().column_ratios.unwrap()[0], Some(0.5));
+    }
+
+    #[test]
+    fn test_workspace_both_rule_no_match() {
+        let ws_base = opts_with_ratio(0.7);
+        let ws_rules = vec![(10, opts_with_ratio(0.5))];
+        let result = resolve_effective_options(3, Some(ws_base), &ws_rules, None, &[]);
+        // Rule doesn't match → fall back to ws_base
+        assert_eq!(result.unwrap().column_ratios, ws_base.column_ratios);
+    }
+}
--- a/komorebi/src/core/mod.rs
+++ b/komorebi/src/core/mod.rs
@@ -32,6 +32,7 @@ pub use komorebi_layouts::DefaultLayout;
 pub use komorebi_layouts::Direction;
 pub use komorebi_layouts::GridLayoutOptions;
 pub use komorebi_layouts::Layout;
+pub use komorebi_layouts::LayoutDefaultEntry;
 pub use komorebi_layouts::LayoutOptions;
 pub use komorebi_layouts::MAX_RATIO;
 pub use komorebi_layouts::MAX_RATIOS;
--- a/komorebi/src/lib.rs
+++ b/komorebi/src/lib.rs
@@ -238,6 +238,9 @@ lazy_static! {
    static ref FLOATING_WINDOW_TOGGLE_ASPECT_RATIO: Arc<Mutex<AspectRatio>> = Arc::new(Mutex::new(AspectRatio::Predefined(PredefinedAspectRatio::Widescreen)));

    static ref CURRENT_VIRTUAL_DESKTOP: Arc<Mutex<Option<Vec<u8>>>> = Arc::new(Mutex::new(None));
+
+    pub static ref LAYOUT_DEFAULTS: Arc<Mutex<HashMap<DefaultLayout, LayoutDefaultEntry>>> =
+        Arc::new(Mutex::new(HashMap::new()));
 }

 pub static DEFAULT_WORKSPACE_PADDING: AtomicI32 = AtomicI32::new(10);
--- a/komorebi/src/state.rs
+++ b/komorebi/src/state.rs
@@ -253,6 +253,8 @@ impl From<&WindowManager> for State {
                            layout: workspace.layout.clone(),
                            layout_options: workspace.layout_options,
                            layout_rules: workspace.layout_rules.clone(),
+                            layout_options_rules: workspace.layout_options_rules.clone(),
+                            layout_defaults_cache: workspace.layout_defaults_cache.clone(),
                            work_area_offset_rules: workspace.work_area_offset_rules.clone(),
                            layout_flip: workspace.layout_flip,
                            workspace_padding: workspace.workspace_padding,
--- a/komorebi/src/static_config.rs
+++ b/komorebi/src/static_config.rs
@@ -13,6 +13,7 @@ use crate::FloatingLayerBehaviour;
 use crate::HIDING_BEHAVIOUR;
 use crate::IGNORE_IDENTIFIERS;
 use crate::LAYERED_WHITELIST;
+use crate::LAYOUT_DEFAULTS;
 use crate::MANAGE_IDENTIFIERS;
 use crate::MONITOR_INDEX_PREFERENCES;
 use crate::NO_TITLEBAR;
@@ -53,6 +54,7 @@ use crate::core::DefaultLayout;
 use crate::core::FocusFollowsMouseImplementation;
 use crate::core::HidingBehaviour;
 use crate::core::Layout;
+use crate::core::LayoutDefaultEntry;
 use crate::core::LayoutOptions;
 use crate::core::MoveBehaviour;
 use crate::core::OperationBehaviour;
@@ -215,6 +217,12 @@ pub struct WorkspaceConfig {
    /// Layout-specific options
    #[serde(skip_serializing_if = "Option::is_none")]
    pub layout_options: Option<LayoutOptions>,
+    /// Threshold-based layout options rules in the format of threshold => options.
+    /// When container count >= threshold, the highest matching threshold's options
+    /// fully replace the base `layout_options`.
+    /// This follows the same threshold logic as `layout_rules`.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub layout_options_rules: Option<HashMap<usize, LayoutOptions>>,
    /// END OF LIFE FEATURE: Custom Layout
    #[deprecated(note = "End of life feature")]
    #[serde(skip_serializing_if = "Option::is_none")]
@@ -342,6 +350,11 @@ impl From<&Workspace> for WorkspaceConfig {
                );
                value.layout_options
            },
+            layout_options_rules: if value.layout_options_rules.is_empty() {
+                None
+            } else {
+                Some(value.layout_options_rules.iter().copied().collect())
+            },
            #[allow(deprecated)]
            custom_layout: value
                .workspace_config
@@ -582,6 +595,11 @@ pub struct StaticConfig {
    #[serde(skip_serializing_if = "Option::is_none")]
    #[cfg_attr(feature = "schemars", schemars(extend("default" = DEFAULT_CONTAINER_PADDING)))]
    pub default_container_padding: Option<i32>,
+    /// Per-layout default options and rules, keyed by layout name.
+    /// Applied as fallback when a workspace does not define its own layout_options or layout_options_rules.
+    /// If a workspace defines either setting, all global defaults for that layout are completely replaced.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub layout_defaults: Option<HashMap<DefaultLayout, LayoutDefaultEntry>>,
    /// Monitor and workspace configurations
    #[serde(skip_serializing_if = "Option::is_none")]
    pub monitors: Option<Vec<MonitorConfig>>,
@@ -891,6 +909,14 @@ impl From<&WindowManager> for StaticConfig {
            default_container_padding: Option::from(
                DEFAULT_CONTAINER_PADDING.load(Ordering::SeqCst),
            ),
+            layout_defaults: {
+                let guard = LAYOUT_DEFAULTS.lock();
+                if guard.is_empty() {
+                    None
+                } else {
+                    Some(guard.clone())
+                }
+            },
            monitors: Option::from(monitors),
            window_hiding_behaviour: Option::from(*HIDING_BEHAVIOUR.lock()),
            global_work_area_offset: value.work_area_offset,
@@ -1006,6 +1032,12 @@ impl StaticConfig {
            DEFAULT_WORKSPACE_PADDING.store(workspace, Ordering::SeqCst);
        }

+        if let Some(defaults) = &self.layout_defaults {
+            *LAYOUT_DEFAULTS.lock() = defaults.clone();
+        } else {
+            LAYOUT_DEFAULTS.lock().clear();
+        }
+
        if let Some(border_width) = self.border_width {
            border_manager::BORDER_WIDTH.store(border_width, Ordering::SeqCst);
        }
@@ -1414,7 +1446,7 @@ impl StaticConfig {
                            workspace_config.layout = Some(DefaultLayout::Columns);
                        }

-                        ws.load_static_config(workspace_config)?;
+                        ws.load_static_config(workspace_config, value.layout_defaults.as_ref())?;
                    }
                }

@@ -1497,7 +1529,10 @@ impl StaticConfig {

                    for (j, ws) in m.workspaces_mut().iter_mut().enumerate() {
                        if let Some(workspace_config) = monitor_config.workspaces.get(j) {
-                            ws.load_static_config(workspace_config)?;
+                            ws.load_static_config(
+                                workspace_config,
+                                value.layout_defaults.as_ref(),
+                            )?;
                        }
                    }

@@ -1579,7 +1614,7 @@ impl StaticConfig {

                for (j, ws) in monitor.workspaces_mut().iter_mut().enumerate() {
                    if let Some(workspace_config) = monitor_config.workspaces.get(j) {
-                        ws.load_static_config(workspace_config)?;
+                        ws.load_static_config(workspace_config, value.layout_defaults.as_ref())?;
                    }
                }

@@ -1662,7 +1697,10 @@ impl StaticConfig {

                    for (j, ws) in m.workspaces_mut().iter_mut().enumerate() {
                        if let Some(workspace_config) = monitor_config.workspaces.get(j) {
-                            ws.load_static_config(workspace_config)?;
+                            ws.load_static_config(
+                                workspace_config,
+                                value.layout_defaults.as_ref(),
+                            )?;
                        }
                    }

--- a/komorebi/src/workspace.rs
+++ b/komorebi/src/workspace.rs
@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::collections::VecDeque;
 use std::ffi::OsStr;
 use std::fmt::Display;
@@ -25,6 +26,7 @@ use crate::core::CustomLayout;
 use crate::core::CycleDirection;
 use crate::core::DefaultLayout;
 use crate::core::Layout;
+use crate::core::LayoutDefaultEntry;
 use crate::core::LayoutOptions;
 use crate::core::OperationDirection;
 use crate::core::Rect;
@@ -61,6 +63,14 @@ pub struct Workspace {
    pub layout: Layout,
    pub layout_options: Option<LayoutOptions>,
    pub layout_rules: Vec<(usize, Layout)>,
+    /// Threshold-based layout options rules (container_count >= threshold -> use these options).
+    /// Sorted by threshold ascending at load time.
+    #[serde(default)]
+    pub layout_options_rules: Vec<(usize, LayoutOptions)>,
+    /// Cached per-layout defaults from the global `layout_defaults` config setting.
+    /// Pre-sorted at config load time; used as fallback when workspace has no overrides.
+    #[serde(skip)]
+    pub(crate) layout_defaults_cache: HashMap<DefaultLayout, CachedLayoutDefault>,
    pub work_area_offset_rules: Vec<(usize, Rect)>,
    pub layout_flip: Option<Axis>,
    pub workspace_padding: Option<i32>,
@@ -119,6 +129,8 @@ impl Default for Workspace {
            layout: Layout::Default(DefaultLayout::BSP),
            layout_options: None,
            layout_rules: vec![],
+            layout_options_rules: vec![],
+            layout_defaults_cache: HashMap::new(),
            work_area_offset_rules: vec![],
            layout_flip: None,
            workspace_padding: Option::from(DEFAULT_WORKSPACE_PADDING.load(Ordering::SeqCst)),
@@ -165,8 +177,49 @@ pub struct WorkspaceGlobals {
    pub floating_layer_behaviour: Option<FloatingLayerBehaviour>,
 }

+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+/// Cached per-layout default options (pre-sorted rules) derived from the global `layout_defaults`.
+pub(crate) struct CachedLayoutDefault {
+    pub layout_options: Option<LayoutOptions>,
+    /// Threshold-based rules, sorted by threshold ascending at load time
+    pub layout_options_rules: Vec<(usize, LayoutOptions)>,
+}
+
+/// Convert an optional HashMap of threshold-based layout options rules into a Vec sorted by
+/// threshold ascending.
+fn sorted_layout_options_rules(
+    rules: Option<&HashMap<usize, LayoutOptions>>,
+) -> Vec<(usize, LayoutOptions)> {
+    match rules {
+        Some(rules) => {
+            let mut sorted: Vec<(usize, LayoutOptions)> =
+                rules.iter().map(|(t, o)| (*t, *o)).collect();
+            sorted.sort_by_key(|(t, _)| *t);
+            sorted
+        }
+        None => vec![],
+    }
+}
+
+/// Find the highest matching threshold rule for the given container count.
+/// Rules must be sorted by threshold ascending.
+fn resolve_threshold_match(
+    rules: &[(usize, LayoutOptions)],
+    container_count: usize,
+) -> Option<LayoutOptions> {
+    rules
+        .iter()
+        .rev()
+        .find(|(threshold, _)| container_count >= *threshold)
+        .map(|(_, opts)| *opts)
+}
+
 impl Workspace {
-    pub fn load_static_config(&mut self, config: &WorkspaceConfig) -> eyre::Result<()> {
+    pub fn load_static_config(
+        &mut self,
+        config: &WorkspaceConfig,
+        layout_defaults: Option<&HashMap<DefaultLayout, LayoutDefaultEntry>>,
+    ) -> eyre::Result<()> {
        self.name = Option::from(config.name.clone());

        self.container_padding = config.container_padding;
@@ -251,19 +304,78 @@ impl Workspace {
        self.layout_flip = config.layout_flip;
        self.floating_layer_behaviour = config.floating_layer_behaviour;
        self.wallpaper = config.wallpaper.clone();
+
+        // Load layout options directly (LayoutOptions is used in both config and runtime)
        self.layout_options = config.layout_options;

+        // Load threshold-based layout options rules, sorted by threshold ascending
+        self.layout_options_rules =
+            sorted_layout_options_rules(config.layout_options_rules.as_ref());
+
        tracing::debug!(
-            "Workspace '{}' loaded layout_options: {:?}",
+            "Workspace '{}' loaded layout_options: {:?}, layout_options_rules: {} entries",
            self.name.as_deref().unwrap_or("unnamed"),
-            self.layout_options
+            self.layout_options,
+            self.layout_options_rules.len(),
        );

+        // Cache per-layout defaults from global layout_defaults, pre-sorting rules
+        self.layout_defaults_cache = if let Some(defaults) = layout_defaults {
+            defaults
+                .iter()
+                .map(|(layout, entry)| {
+                    (
+                        *layout,
+                        CachedLayoutDefault {
+                            layout_options: entry.layout_options,
+                            layout_options_rules: sorted_layout_options_rules(
+                                entry.layout_options_rules.as_ref(),
+                            ),
+                        },
+                    )
+                })
+                .collect()
+        } else {
+            HashMap::new()
+        };
+
        self.workspace_config = Some(config.clone());

        Ok(())
    }

+    /// Compute effective layout options using the complete-replacement cascade:
+    ///
+    /// If the workspace defines EITHER `layout_options` OR `layout_options_rules`,
+    /// it completely replaces the global `layout_defaults` for this layout.
+    /// Global defaults are only used when the workspace has NEITHER setting.
+    ///
+    /// Within the effective source (workspace or global):
+    ///   1. Try threshold match from rules (highest matching threshold wins)
+    ///   2. If a rule matches -> use it (full replacement of base)
+    ///   3. Else -> use the base `layout_options`
+    fn effective_layout_options(&self) -> Option<LayoutOptions> {
+        let container_count = self.containers().len();
+
+        let has_workspace_overrides =
+            self.layout_options.is_some() || !self.layout_options_rules.is_empty();
+
+        let (effective_base, effective_rules): (Option<LayoutOptions>, &[(usize, LayoutOptions)]) =
+            if has_workspace_overrides {
+                (self.layout_options, &self.layout_options_rules)
+            } else {
+                match &self.layout {
+                    Layout::Default(dl) => match self.layout_defaults_cache.get(dl) {
+                        Some(entry) => (entry.layout_options, &entry.layout_options_rules),
+                        None => (None, &[]),
+                    },
+                    Layout::Custom(_) => (None, &[]),
+                }
+            };
+
+        resolve_threshold_match(effective_rules, container_count).or(effective_base)
+    }
+
    pub fn hide(&mut self, omit: Option<isize>) {
        for window in self.floating_windows_mut().iter_mut().rev() {
            let mut should_hide = omit.is_none();
@@ -584,10 +696,14 @@ impl Workspace {
            } else if let Some(window) = &mut self.maximized_window {
                window.maximize();
            } else if !self.containers().is_empty() {
+                let effective_layout_options = self.effective_layout_options();
+
                tracing::debug!(
-                    "Workspace '{}' update() - self.layout_options before calculate: {:?}",
+                    "Workspace '{}' update() - effective_layout_options: {:?} (base: {:?}, rules: {})",
                    self.name.as_deref().unwrap_or("unnamed"),
-                    self.layout_options
+                    effective_layout_options,
+                    self.layout_options,
+                    self.layout_options_rules.len(),
                );
                let mut layouts = self.layout.as_boxed_arrangement().calculate(
                    &adjusted_work_area,
@@ -598,7 +714,7 @@ impl Workspace {
                    self.layout_flip,
                    &self.resize_dimensions,
                    self.focused_container_idx(),
-                    self.layout_options,
+                    effective_layout_options,
                    &self.latest_layout,
                );

--- a/schema.bar.json
+++ b/schema.bar.json
@@ -9683,6 +9683,26 @@
            }
          ]
        },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules (container_count >= threshold -> use these options).\nSorted by threshold ascending at load time.",
+          "type": "array",
+          "default": [],
+          "items": {
+            "type": "array",
+            "maxItems": 2,
+            "minItems": 2,
+            "prefixItems": [
+              {
+                "type": "integer",
+                "format": "uint",
+                "minimum": 0
+              },
+              {
+                "$ref": "#/$defs/LayoutOptions"
+              }
+            ]
+          }
+        },
        "layout_rules": {
          "type": "array",
          "items": {
@@ -9985,6 +10005,19 @@
            }
          ]
        },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules in the format of threshold => options.\nWhen container count >= threshold, the highest matching threshold's options\nfully replace the base `layout_options`.\nThis follows the same threshold logic as `layout_rules`.",
+          "type": [
+            "object",
+            "null"
+          ],
+          "additionalProperties": false,
+          "patternProperties": {
+            "^\\d+$": {
+              "$ref": "#/$defs/LayoutOptions"
+            }
+          }
+        },
        "layout_rules": {
          "description": "Layout rules in the format of threshold => layout",
          "type": [
--- a/schema.json
+++ b/schema.json
@@ -304,6 +304,16 @@
        "$ref": "#/$defs/MatchingRule"
      }
    },
+    "layout_defaults": {
+      "description": "Per-layout default options and rules, keyed by layout name.\nApplied as fallback when a workspace does not define its own layout_options or layout_options_rules.\nIf a workspace defines either setting, all global defaults for that layout are completely replaced.",
+      "type": [
+        "object",
+        "null"
+      ],
+      "additionalProperties": {
+        "$ref": "#/$defs/LayoutDefaultEntry"
+      }
+    },
    "manage_rules": {
      "description": "Individual window force-manage rules",
      "type": [
@@ -3290,6 +3300,36 @@
        "colours"
      ]
    },
+    "LayoutDefaultEntry": {
+      "description": "Per-layout default options entry for the `layout_defaults` global setting.\nContains both base layout options and threshold-based layout options rules.",
+      "type": "object",
+      "properties": {
+        "layout_options": {
+          "description": "Default layout options for this layout",
+          "anyOf": [
+            {
+              "$ref": "#/$defs/LayoutOptions"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules in the format of threshold => options.\nWhen container count >= threshold, the highest matching threshold's options\nfully replace the base `layout_options`.",
+          "type": [
+            "object",
+            "null"
+          ],
+          "additionalProperties": false,
+          "patternProperties": {
+            "^\\d+$": {
+              "$ref": "#/$defs/LayoutOptions"
+            }
+          }
+        }
+      }
+    },
    "LayoutOptions": {
      "description": "Options for specific layouts",
      "type": "object",
@@ -4214,6 +4254,19 @@
            }
          ]
        },
+        "layout_options_rules": {
+          "description": "Threshold-based layout options rules in the format of threshold => options.\nWhen container count >= threshold, the highest matching threshold's options\nfully replace the base `layout_options`.\nThis follows the same threshold logic as `layout_rules`.",
+          "type": [
+            "object",
+            "null"
+          ],
+          "additionalProperties": false,
+          "patternProperties": {
+            "^\\d+$": {
+              "$ref": "#/$defs/LayoutOptions"
+            }
+          }
+        },
        "layout_rules": {
          "description": "Layout rules in the format of threshold => layout",
          "type": [