feat(core): Add support for custom aliases for model configs.

docs/get-started/configuration.md

@@ -361,10 +361,10 @@
           }
         }
       },
       "gemini-3-pro-preview": {
         "extends": "chat-base-3",
         "modelConfig": {
           "model": "gemini-3-pro-preview"
         }
       },
       "gemini-2.5-pro": {
@@ -494,6 +494,11 @@
     }
     ```
 
+- **`modelConfigs.customAliases`** (object):
+  - **Description:** Custom named presets for model configs. These are merged
+    with (and override) the built-in aliases.
+  - **Default:** `{}`
+
 - **`modelConfigs.overrides`** (array):
   - **Description:** Apply specific configuration overrides based on matches,
     with a primary key of model (or alias). The most specific match will be

packages/cli/src/config/settingsSchema.ts

@@ -729,6 +729,16 @@ const SETTINGS_SCHEMA = {
           'Named presets for model configs. Can be used in place of a model name and can inherit from other aliases using an `extends` property.',
         showInDialog: false,
       },
+      customAliases: {
+        type: 'object',
+        label: 'Custom Model Config Aliases',
+        category: 'Model',
+        requiresRestart: false,
+        default: {},
+        description:
+          'Custom named presets for model configs. These are merged with (and override) the built-in aliases.',
+        showInDialog: false,
+      },
       overrides: {
         type: 'array',
         label: 'Model Config Overrides',

packages/core/src/services/modelConfigService.test.ts

@@ -576,4 +576,125 @@ describe('ModelConfigService', () => {
       });
     });
   });
+
+  describe('custom aliases', () => {
+    it('should resolve a custom alias', () => {
+      const config: ModelConfigServiceConfig = {
+        aliases: {},
+        customAliases: {
+          'my-custom-alias': {
+            modelConfig: {
+              model: 'gemini-custom',
+              generateContentConfig: {
+                temperature: 0.9,
+              },
+            },
+          },
+        },
+        overrides: [],
+      };
+      const service = new ModelConfigService(config);
+      const resolved = service.getResolvedConfig({ model: 'my-custom-alias' });
+
+      expect(resolved.model).toBe('gemini-custom');
+      expect(resolved.generateContentConfig).toEqual({
+        temperature: 0.9,
+      });
+    });
+
+    it('should allow custom aliases to override built-in aliases', () => {
+      const config: ModelConfigServiceConfig = {
+        aliases: {
+          'standard-alias': {
+            modelConfig: {
+              model: 'gemini-standard',
+              generateContentConfig: {
+                temperature: 0.5,
+              },
+            },
+          },
+        },
+        customAliases: {
+          'standard-alias': {
+            modelConfig: {
+              model: 'gemini-custom-override',
+              generateContentConfig: {
+                temperature: 0.1,
+              },
+            },
+          },
+        },
+        overrides: [],
+      };
+      const service = new ModelConfigService(config);
+      const resolved = service.getResolvedConfig({ model: 'standard-alias' });
+
+      expect(resolved.model).toBe('gemini-custom-override');
+      expect(resolved.generateContentConfig).toEqual({
+        temperature: 0.1,
+      });
+    });
+  });
+
+  describe('unrecognized models', () => {
+    it('should apply overrides to unrecognized model names', () => {
+      const unregisteredModelName = 'my-unregistered-model-v1';
+      const config: ModelConfigServiceConfig = {
+        aliases: {}, // No aliases defined
+        overrides: [
+          {
+            match: { model: unregisteredModelName },
+            modelConfig: {
+              generateContentConfig: {
+                temperature: 0.01,
+              },
+            },
+          },
+        ],
+      };
+      const service = new ModelConfigService(config);
+
+      // Request the unregistered model directly
+      const resolved = service.getResolvedConfig({
+        model: unregisteredModelName,
+      });
+
+      // It should preserve the model name and apply the override
+      expect(resolved.model).toBe(unregisteredModelName);
+      expect(resolved.generateContentConfig).toEqual({
+        temperature: 0.01,
+      });
+    });
+
+    it('should apply scoped overrides to unrecognized model names', () => {
+      const unregisteredModelName = 'my-unregistered-model-v1';
+      const config: ModelConfigServiceConfig = {
+        aliases: {},
+        overrides: [
+          {
+            match: {
+              model: unregisteredModelName,
+              overrideScope: 'special-agent',
+            },
+            modelConfig: {
+              generateContentConfig: {
+                temperature: 0.99,
+              },
+            },
+          },
+        ],
+      };
+      const service = new ModelConfigService(config);
+
+      const resolved = service.getResolvedConfig({
+        model: unregisteredModelName,
+        overrideScope: 'special-agent',
+      });
+
+      expect(resolved.model).toBe(unregisteredModelName);
+      expect(resolved.generateContentConfig).toEqual({
+        temperature: 0.99,
+      });
+    });
+  });
 });

packages/core/src/services/modelConfigService.ts

@@ -43,6 +43,7 @@ export interface ModelConfigAlias {
 
 export interface ModelConfigServiceConfig {
   aliases?: Record<string, ModelConfigAlias>;
+  customAliases?: Record<string, ModelConfigAlias>;
   overrides?: ModelConfigOverride[];
 }
 
@@ -104,8 +105,12 @@ export class ModelConfigService {
     generateContentConfig: GenerateContentConfig;
   } {
     const config = this.config || {};
-    const { aliases = {}, overrides = [] } = config;
-    const allAliases = { ...aliases, ...this.runtimeAliases };
+    const { aliases = {}, customAliases = {}, overrides = [] } = config;
+    const allAliases = {
+      ...aliases,
+      ...customAliases,
+      ...this.runtimeAliases,
+    };
     let baseModel: string | undefined = context.model;
     let resolvedConfig: GenerateContentConfig = {};
 

schemas/settings.schema.json

@@ -436,7 +436,7 @@
     "modelConfigs": {
       "title": "Model Configs",
       "description": "Model configurations.",
       "markdownDescription": "Model configurations.\n\n- Category: `Model`\n- Requires restart: `no`\n- Default: `{\n  \"aliases\": {\n    \"base\": {\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"temperature\": 0,\n          \"topP\": 1\n        }\n      }\n    },\n    \"chat-base\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"thinkingConfig\": {\n            \"includeThoughts\": true\n          },\n          \"temperature\": 1,\n          \"topP\": 0.95,\n          \"topK\": 64\n        }\n      }\n    },\n    \"chat-base-2.5\": {\n      \"extends\": \"chat-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"thinkingConfig\": {\n            \"thinkingBudget\": 8192\n          }\n        }\n      }\n    },\n    \"chat-base-3\": {\n      \"extends\": \"chat-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"thinkingConfig\": {\n            \"thinkingLevel\": \"HIGH\"\n          }\n        }\n      }\n    },\n    \"gemini-3-pro-preview\": {\n      \"extends\": \"chat-base-3\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    },\n    \"gemini-2.5-pro\": {\n      \"extends\": \"chat-base-2.5\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-pro\"\n      }\n    },\n    \"gemini-2.5-flash\": {\n      \"extends\": \"chat-base-2.5\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash\"\n      }\n    },\n    \"gemini-2.5-flash-lite\": {\n      \"extends\": \"chat-base-2.5\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\"\n      }\n    },\n    \"gemini-2.5-flash-base\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash\"\n      }\n    },\n    \"classifier\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"maxOutputTokens\": 1024,\n          \"thinkingConfig\": {\n            \"thinkingBudget\": 512\n          }\n        }\n      }\n    },\n    \"prompt-completion\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"temperature\": 0.3,\n          \"maxOutputTokens\": 16000,\n          \"thinkingConfig\": {\n            \"thinkingBudget\": 0\n          }\n        }\n      }\n    },\n    \"edit-corrector\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"thinkingConfig\": {\n            \"thinkingBudget\": 0\n          }\n        }\n      }\n    },\n    \"summarizer-default\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"maxOutputTokens\": 2000\n        }\n      }\n    },\n    \"summarizer-shell\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"maxOutputTokens\": 2000\n        }\n      }\n    },\n    \"web-search\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"googleSearch\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"urlContext\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch-fallback\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection-double-check\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-pro\"\n      }\n    },\n    \"llm-edit-fixer\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"next-speaker-checker\": {\n      \"extends\": \"gemini-2.5-flash-base\",\n      \"modelConfig\": {}\n    }\n  }\n}`",
       "default": {
         "aliases": {
           "base": {
@@ -480,10 +480,10 @@
               }
             }
           },
           "gemini-3-pro-preview": {
             "extends": "chat-base-3",
             "modelConfig": {
               "model": "gemini-3-pro-preview"
             }
           },
           "gemini-2.5-pro": {
@@ -617,7 +617,7 @@
         "aliases": {
           "title": "Model Config Aliases",
           "description": "Named presets for model configs. Can be used in place of a model name and can inherit from other aliases using an `extends` property.",
           "markdownDescription": "Named presets for model configs. Can be used in place of a model name and can inherit from other aliases using an `extends` property.\n\n- Category: `Model`\n- Requires restart: `no`\n- Default: `{\n  \"base\": {\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"temperature\": 0,\n        \"topP\": 1\n      }\n    }\n  },\n  \"chat-base\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"thinkingConfig\": {\n          \"includeThoughts\": true\n        },\n        \"temperature\": 1,\n        \"topP\": 0.95,\n        \"topK\": 64\n      }\n    }\n  },\n  \"chat-base-2.5\": {\n    \"extends\": \"chat-base\",\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"thinkingConfig\": {\n          \"thinkingBudget\": 8192\n        }\n      }\n    }\n  },\n  \"chat-base-3\": {\n    \"extends\": \"chat-base\",\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"thinkingConfig\": {\n          \"thinkingLevel\": \"HIGH\"\n        }\n      }\n    }\n  },\n  \"gemini-3-pro-preview\": {\n    \"extends\": \"chat-base-3\",\n    \"modelConfig\": {\n      \"model\": \"gemini-3-pro-preview\"\n    }\n  },\n  \"gemini-2.5-pro\": {\n    \"extends\": \"chat-base-2.5\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-pro\"\n    }\n  },\n  \"gemini-2.5-flash\": {\n    \"extends\": \"chat-base-2.5\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash\"\n    }\n  },\n  \"gemini-2.5-flash-lite\": {\n    \"extends\": \"chat-base-2.5\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\"\n    }\n  },\n  \"gemini-2.5-flash-base\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash\"\n    }\n  },\n  \"classifier\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\",\n      \"generateContentConfig\": {\n        \"maxOutputTokens\": 1024,\n        \"thinkingConfig\": {\n          \"thinkingBudget\": 512\n        }\n      }\n    }\n  },\n  \"prompt-completion\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\",\n      \"generateContentConfig\": {\n        \"temperature\": 0.3,\n        \"maxOutputTokens\": 16000,\n        \"thinkingConfig\": {\n          \"thinkingBudget\": 0\n        }\n      }\n    }\n  },\n  \"edit-corrector\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\",\n      \"generateContentConfig\": {\n        \"thinkingConfig\": {\n          \"thinkingBudget\": 0\n        }\n      }\n    }\n  },\n  \"summarizer-default\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\",\n      \"generateContentConfig\": {\n        \"maxOutputTokens\": 2000\n      }\n    }\n  },\n  \"summarizer-shell\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-flash-lite\",\n      \"generateContentConfig\": {\n        \"maxOutputTokens\": 2000\n      }\n    }\n  },\n  \"web-search\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"tools\": [\n          {\n            \"googleSearch\": {}\n          }\n        ]\n      }\n    }\n  },\n  \"web-fetch\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {\n      \"generateContentConfig\": {\n        \"tools\": [\n          {\n            \"urlContext\": {}\n          }\n        ]\n      }\n    }\n  },\n  \"web-fetch-fallback\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {}\n  },\n  \"loop-detection\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {}\n  },\n  \"loop-detection-double-check\": {\n    \"extends\": \"base\",\n    \"modelConfig\": {\n      \"model\": \"gemini-2.5-pro\"\n    }\n  },\n  \"llm-edit-fixer\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {}\n  },\n  \"next-speaker-checker\": {\n    \"extends\": \"gemini-2.5-flash-base\",\n    \"modelConfig\": {}\n  }\n}`",
           "default": {
             "base": {
               "modelConfig": {
@@ -660,10 +660,10 @@
                 }
               }
             },
             "gemini-3-pro-preview": {
               "extends": "chat-base-3",
               "modelConfig": {
                 "model": "gemini-3-pro-preview"
               }
             },
             "gemini-2.5-pro": {
@@ -794,6 +794,14 @@
           "type": "object",
           "additionalProperties": true
         },
+        "customAliases": {
+          "title": "Custom Model Config Aliases",
+          "description": "Custom named presets for model configs. These are merged with (and override) the built-in aliases.",
+          "markdownDescription": "Custom named presets for model configs. These are merged with (and override) the built-in aliases.\n\n- Category: `Model`\n- Requires restart: `no`\n- Default: `{}`",
+          "default": {},
+          "type": "object",
+          "additionalProperties": true
+        },
         "overrides": {
           "title": "Model Config Overrides",
           "description": "Apply specific configuration overrides based on matches, with a primary key of model (or alias). The most specific match will be used.",