diff --git a/docs/reference/configuration.md b/docs/reference/configuration.md
index f3194c39f9..bfea197530 100644
--- a/docs/reference/configuration.md
+++ b/docs/reference/configuration.md
@@ -672,6 +672,141 @@ their corresponding top-level category object in your `settings.json` file.
     used.
   - **Default:** `[]`
 
+- **`modelConfigs.modelDefinitions`** (object):
+  - **Description:** Registry of model metadata, including tier, family, and
+    features.
+  - **Default:**
+
+    ```json
+    {
+      "gemini-3.1-pro-preview": {
+        "tier": "pro",
+        "family": "gemini-3",
+        "isPreview": true,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": true
+        }
+      },
+      "gemini-3.1-pro-preview-customtools": {
+        "tier": "pro",
+        "family": "gemini-3",
+        "isPreview": true,
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": true
+        }
+      },
+      "gemini-3-pro-preview": {
+        "tier": "pro",
+        "family": "gemini-3",
+        "isPreview": true,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": true
+        }
+      },
+      "gemini-3-flash-preview": {
+        "tier": "flash",
+        "family": "gemini-3",
+        "isPreview": true,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": true
+        }
+      },
+      "gemini-2.5-pro": {
+        "tier": "pro",
+        "family": "gemini-2.5",
+        "isPreview": false,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      },
+      "gemini-2.5-flash": {
+        "tier": "flash",
+        "family": "gemini-2.5",
+        "isPreview": false,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      },
+      "gemini-2.5-flash-lite": {
+        "tier": "flash-lite",
+        "family": "gemini-2.5",
+        "isPreview": false,
+        "dialogLocation": "manual",
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      },
+      "auto": {
+        "tier": "auto",
+        "isPreview": true,
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": false
+        }
+      },
+      "pro": {
+        "tier": "pro",
+        "isPreview": false,
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": false
+        }
+      },
+      "flash": {
+        "tier": "flash",
+        "isPreview": false,
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      },
+      "flash-lite": {
+        "tier": "flash-lite",
+        "isPreview": false,
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      },
+      "auto-gemini-3": {
+        "displayName": "Auto (Gemini 3)",
+        "tier": "auto",
+        "isPreview": true,
+        "dialogLocation": "main",
+        "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-3.1-pro, gemini-3-flash",
+        "features": {
+          "thinking": true,
+          "multimodalToolUse": false
+        }
+      },
+      "auto-gemini-2.5": {
+        "displayName": "Auto (Gemini 2.5)",
+        "tier": "auto",
+        "isPreview": false,
+        "dialogLocation": "main",
+        "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-2.5-pro, gemini-2.5-flash",
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": false
+        }
+      }
+    }
+    ```
+
+  - **Requires restart:** Yes
+
 #### `agents`
 
 - **`agents.overrides`** (object):
@@ -1063,6 +1198,12 @@ their corresponding top-level category object in your `settings.json` file.
   - **Default:** `false`
   - **Requires restart:** Yes
 
+- **`experimental.dynamicModelConfiguration`** (boolean):
+  - **Description:** Enable dynamic model configuration (definitions,
+    resolutions, and chains) via settings.
+  - **Default:** `false`
+  - **Requires restart:** Yes
+
 - **`experimental.gemmaModelRouter.enabled`** (boolean):
   - **Description:** Enable the Gemma Model Router (experimental). Requires a
     local endpoint serving Gemma via the Gemini API using LiteRT-LM shim.
diff --git a/schemas/settings.schema.json b/schemas/settings.schema.json
index c8c28af062..e11ef4f6fc 100644
--- a/schemas/settings.schema.json
+++ b/schemas/settings.schema.json
@@ -622,7 +622,7 @@
     "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-3-flash-preview\": {\n      \"extends\": \"chat-base-3\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-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    \"gemini-3-flash-base\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-preview\"\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    \"fast-ack-helper\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"temperature\": 0.2,\n          \"maxOutputTokens\": 120,\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-3-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"googleSearch\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"urlContext\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch-fallback\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection-double-check\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    },\n    \"llm-edit-fixer\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"next-speaker-checker\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"chat-compression-3-pro\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    },\n    \"chat-compression-3-flash\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-preview\"\n      }\n    },\n    \"chat-compression-2.5-pro\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-pro\"\n      }\n    },\n    \"chat-compression-2.5-flash\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash\"\n      }\n    },\n    \"chat-compression-2.5-flash-lite\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\"\n      }\n    },\n    \"chat-compression-default\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    }\n  },\n  \"overrides\": [\n    {\n      \"match\": {\n        \"model\": \"chat-base\",\n        \"isRetry\": true\n      },\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"temperature\": 1\n        }\n      }\n    }\n  ]\n}`",
+      "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-3-flash-preview\": {\n      \"extends\": \"chat-base-3\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-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    \"gemini-3-flash-base\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-preview\"\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    \"fast-ack-helper\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\",\n        \"generateContentConfig\": {\n          \"temperature\": 0.2,\n          \"maxOutputTokens\": 120,\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-3-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"googleSearch\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"tools\": [\n            {\n              \"urlContext\": {}\n            }\n          ]\n        }\n      }\n    },\n    \"web-fetch-fallback\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"loop-detection-double-check\": {\n      \"extends\": \"base\",\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    },\n    \"llm-edit-fixer\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"next-speaker-checker\": {\n      \"extends\": \"gemini-3-flash-base\",\n      \"modelConfig\": {}\n    },\n    \"chat-compression-3-pro\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    },\n    \"chat-compression-3-flash\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-flash-preview\"\n      }\n    },\n    \"chat-compression-2.5-pro\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-pro\"\n      }\n    },\n    \"chat-compression-2.5-flash\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash\"\n      }\n    },\n    \"chat-compression-2.5-flash-lite\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-2.5-flash-lite\"\n      }\n    },\n    \"chat-compression-default\": {\n      \"modelConfig\": {\n        \"model\": \"gemini-3-pro-preview\"\n      }\n    }\n  },\n  \"overrides\": [\n    {\n      \"match\": {\n        \"model\": \"chat-base\",\n        \"isRetry\": true\n      },\n      \"modelConfig\": {\n        \"generateContentConfig\": {\n          \"temperature\": 1\n        }\n      }\n    }\n  ],\n  \"modelDefinitions\": {\n    \"gemini-3.1-pro-preview\": {\n      \"tier\": \"pro\",\n      \"family\": \"gemini-3\",\n      \"isPreview\": true,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": true\n      }\n    },\n    \"gemini-3.1-pro-preview-customtools\": {\n      \"tier\": \"pro\",\n      \"family\": \"gemini-3\",\n      \"isPreview\": true,\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": true\n      }\n    },\n    \"gemini-3-pro-preview\": {\n      \"tier\": \"pro\",\n      \"family\": \"gemini-3\",\n      \"isPreview\": true,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": true\n      }\n    },\n    \"gemini-3-flash-preview\": {\n      \"tier\": \"flash\",\n      \"family\": \"gemini-3\",\n      \"isPreview\": true,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": true\n      }\n    },\n    \"gemini-2.5-pro\": {\n      \"tier\": \"pro\",\n      \"family\": \"gemini-2.5\",\n      \"isPreview\": false,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"gemini-2.5-flash\": {\n      \"tier\": \"flash\",\n      \"family\": \"gemini-2.5\",\n      \"isPreview\": false,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"gemini-2.5-flash-lite\": {\n      \"tier\": \"flash-lite\",\n      \"family\": \"gemini-2.5\",\n      \"isPreview\": false,\n      \"dialogLocation\": \"manual\",\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"auto\": {\n      \"tier\": \"auto\",\n      \"isPreview\": true,\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"pro\": {\n      \"tier\": \"pro\",\n      \"isPreview\": false,\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"flash\": {\n      \"tier\": \"flash\",\n      \"isPreview\": false,\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"flash-lite\": {\n      \"tier\": \"flash-lite\",\n      \"isPreview\": false,\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"auto-gemini-3\": {\n      \"displayName\": \"Auto (Gemini 3)\",\n      \"tier\": \"auto\",\n      \"isPreview\": true,\n      \"dialogLocation\": \"main\",\n      \"dialogDescription\": \"Let Gemini CLI decide the best model for the task: gemini-3.1-pro, gemini-3-flash\",\n      \"features\": {\n        \"thinking\": true,\n        \"multimodalToolUse\": false\n      }\n    },\n    \"auto-gemini-2.5\": {\n      \"displayName\": \"Auto (Gemini 2.5)\",\n      \"tier\": \"auto\",\n      \"isPreview\": false,\n      \"dialogLocation\": \"main\",\n      \"dialogDescription\": \"Let Gemini CLI decide the best model for the task: gemini-2.5-pro, gemini-2.5-flash\",\n      \"features\": {\n        \"thinking\": false,\n        \"multimodalToolUse\": false\n      }\n    }\n  }\n}`",
       "default": {
         "aliases": {
           "base": {
@@ -864,7 +864,132 @@
               }
             }
           }
-        ]
+        ],
+        "modelDefinitions": {
+          "gemini-3.1-pro-preview": {
+            "tier": "pro",
+            "family": "gemini-3",
+            "isPreview": true,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": true
+            }
+          },
+          "gemini-3.1-pro-preview-customtools": {
+            "tier": "pro",
+            "family": "gemini-3",
+            "isPreview": true,
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": true
+            }
+          },
+          "gemini-3-pro-preview": {
+            "tier": "pro",
+            "family": "gemini-3",
+            "isPreview": true,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": true
+            }
+          },
+          "gemini-3-flash-preview": {
+            "tier": "flash",
+            "family": "gemini-3",
+            "isPreview": true,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": true
+            }
+          },
+          "gemini-2.5-pro": {
+            "tier": "pro",
+            "family": "gemini-2.5",
+            "isPreview": false,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          },
+          "gemini-2.5-flash": {
+            "tier": "flash",
+            "family": "gemini-2.5",
+            "isPreview": false,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          },
+          "gemini-2.5-flash-lite": {
+            "tier": "flash-lite",
+            "family": "gemini-2.5",
+            "isPreview": false,
+            "dialogLocation": "manual",
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          },
+          "auto": {
+            "tier": "auto",
+            "isPreview": true,
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": false
+            }
+          },
+          "pro": {
+            "tier": "pro",
+            "isPreview": false,
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": false
+            }
+          },
+          "flash": {
+            "tier": "flash",
+            "isPreview": false,
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          },
+          "flash-lite": {
+            "tier": "flash-lite",
+            "isPreview": false,
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          },
+          "auto-gemini-3": {
+            "displayName": "Auto (Gemini 3)",
+            "tier": "auto",
+            "isPreview": true,
+            "dialogLocation": "main",
+            "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-3.1-pro, gemini-3-flash",
+            "features": {
+              "thinking": true,
+              "multimodalToolUse": false
+            }
+          },
+          "auto-gemini-2.5": {
+            "displayName": "Auto (Gemini 2.5)",
+            "tier": "auto",
+            "isPreview": false,
+            "dialogLocation": "main",
+            "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-2.5-pro, gemini-2.5-flash",
+            "features": {
+              "thinking": false,
+              "multimodalToolUse": false
+            }
+          }
+        }
       },
       "type": "object",
       "properties": {
@@ -1126,6 +1251,140 @@
           "default": [],
           "type": "array",
           "items": {}
+        },
+        "modelDefinitions": {
+          "title": "Model Definitions",
+          "description": "Registry of model metadata, including tier, family, and features.",
+          "markdownDescription": "Registry of model metadata, including tier, family, and features.\n\n- Category: `Model`\n- Requires restart: `yes`\n- Default: `{\n  \"gemini-3.1-pro-preview\": {\n    \"tier\": \"pro\",\n    \"family\": \"gemini-3\",\n    \"isPreview\": true,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": true\n    }\n  },\n  \"gemini-3.1-pro-preview-customtools\": {\n    \"tier\": \"pro\",\n    \"family\": \"gemini-3\",\n    \"isPreview\": true,\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": true\n    }\n  },\n  \"gemini-3-pro-preview\": {\n    \"tier\": \"pro\",\n    \"family\": \"gemini-3\",\n    \"isPreview\": true,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": true\n    }\n  },\n  \"gemini-3-flash-preview\": {\n    \"tier\": \"flash\",\n    \"family\": \"gemini-3\",\n    \"isPreview\": true,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": true\n    }\n  },\n  \"gemini-2.5-pro\": {\n    \"tier\": \"pro\",\n    \"family\": \"gemini-2.5\",\n    \"isPreview\": false,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"gemini-2.5-flash\": {\n    \"tier\": \"flash\",\n    \"family\": \"gemini-2.5\",\n    \"isPreview\": false,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"gemini-2.5-flash-lite\": {\n    \"tier\": \"flash-lite\",\n    \"family\": \"gemini-2.5\",\n    \"isPreview\": false,\n    \"dialogLocation\": \"manual\",\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"auto\": {\n    \"tier\": \"auto\",\n    \"isPreview\": true,\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"pro\": {\n    \"tier\": \"pro\",\n    \"isPreview\": false,\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"flash\": {\n    \"tier\": \"flash\",\n    \"isPreview\": false,\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"flash-lite\": {\n    \"tier\": \"flash-lite\",\n    \"isPreview\": false,\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"auto-gemini-3\": {\n    \"displayName\": \"Auto (Gemini 3)\",\n    \"tier\": \"auto\",\n    \"isPreview\": true,\n    \"dialogLocation\": \"main\",\n    \"dialogDescription\": \"Let Gemini CLI decide the best model for the task: gemini-3.1-pro, gemini-3-flash\",\n    \"features\": {\n      \"thinking\": true,\n      \"multimodalToolUse\": false\n    }\n  },\n  \"auto-gemini-2.5\": {\n    \"displayName\": \"Auto (Gemini 2.5)\",\n    \"tier\": \"auto\",\n    \"isPreview\": false,\n    \"dialogLocation\": \"main\",\n    \"dialogDescription\": \"Let Gemini CLI decide the best model for the task: gemini-2.5-pro, gemini-2.5-flash\",\n    \"features\": {\n      \"thinking\": false,\n      \"multimodalToolUse\": false\n    }\n  }\n}`",
+          "default": {
+            "gemini-3.1-pro-preview": {
+              "tier": "pro",
+              "family": "gemini-3",
+              "isPreview": true,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": true
+              }
+            },
+            "gemini-3.1-pro-preview-customtools": {
+              "tier": "pro",
+              "family": "gemini-3",
+              "isPreview": true,
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": true
+              }
+            },
+            "gemini-3-pro-preview": {
+              "tier": "pro",
+              "family": "gemini-3",
+              "isPreview": true,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": true
+              }
+            },
+            "gemini-3-flash-preview": {
+              "tier": "flash",
+              "family": "gemini-3",
+              "isPreview": true,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": true
+              }
+            },
+            "gemini-2.5-pro": {
+              "tier": "pro",
+              "family": "gemini-2.5",
+              "isPreview": false,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            },
+            "gemini-2.5-flash": {
+              "tier": "flash",
+              "family": "gemini-2.5",
+              "isPreview": false,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            },
+            "gemini-2.5-flash-lite": {
+              "tier": "flash-lite",
+              "family": "gemini-2.5",
+              "isPreview": false,
+              "dialogLocation": "manual",
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            },
+            "auto": {
+              "tier": "auto",
+              "isPreview": true,
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": false
+              }
+            },
+            "pro": {
+              "tier": "pro",
+              "isPreview": false,
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": false
+              }
+            },
+            "flash": {
+              "tier": "flash",
+              "isPreview": false,
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            },
+            "flash-lite": {
+              "tier": "flash-lite",
+              "isPreview": false,
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            },
+            "auto-gemini-3": {
+              "displayName": "Auto (Gemini 3)",
+              "tier": "auto",
+              "isPreview": true,
+              "dialogLocation": "main",
+              "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-3.1-pro, gemini-3-flash",
+              "features": {
+                "thinking": true,
+                "multimodalToolUse": false
+              }
+            },
+            "auto-gemini-2.5": {
+              "displayName": "Auto (Gemini 2.5)",
+              "tier": "auto",
+              "isPreview": false,
+              "dialogLocation": "main",
+              "dialogDescription": "Let Gemini CLI decide the best model for the task: gemini-2.5-pro, gemini-2.5-flash",
+              "features": {
+                "thinking": false,
+                "multimodalToolUse": false
+              }
+            }
+          },
+          "type": "object",
+          "additionalProperties": {
+            "$ref": "#/$defs/ModelDefinition"
+          }
         }
       },
       "additionalProperties": false
@@ -1769,6 +2028,13 @@
           "default": false,
           "type": "boolean"
         },
+        "dynamicModelConfiguration": {
+          "title": "Dynamic Model Configuration",
+          "description": "Enable dynamic model configuration (definitions, resolutions, and chains) via settings.",
+          "markdownDescription": "Enable dynamic model configuration (definitions, resolutions, and chains) via settings.\n\n- Category: `Experimental`\n- Requires restart: `yes`\n- Default: `false`",
+          "default": false,
+          "type": "boolean"
+        },
         "gemmaModelRouter": {
           "title": "Gemma Model Router",
           "description": "Enable Gemma model router (experimental).",
@@ -2523,6 +2789,41 @@
           }
         }
       }
+    },
+    "ModelDefinition": {
+      "type": "object",
+      "description": "Model metadata registry entry.",
+      "properties": {
+        "displayName": {
+          "type": "string"
+        },
+        "tier": {
+          "enum": ["pro", "flash", "flash-lite", "custom", "auto"]
+        },
+        "family": {
+          "type": "string"
+        },
+        "isPreview": {
+          "type": "boolean"
+        },
+        "dialogLocation": {
+          "enum": ["main", "manual"]
+        },
+        "dialogDescription": {
+          "type": "string"
+        },
+        "features": {
+          "type": "object",
+          "properties": {
+            "thinking": {
+              "type": "boolean"
+            },
+            "multimodalToolUse": {
+              "type": "boolean"
+            }
+          }
+        }
+      }
     }
   }
 }