feat(core, cli): Add support for agents in settings.json. (#16433)

schemas/settings.schema.json

@@ -926,6 +926,26 @@
       },
       "additionalProperties": false
     },
+    "agents": {
+      "title": "Agents",
+      "description": "Settings for subagents.",
+      "markdownDescription": "Settings for subagents.\n\n- Category: `Advanced`\n- Requires restart: `yes`\n- Default: `{}`",
+      "default": {},
+      "type": "object",
+      "properties": {
+        "overrides": {
+          "title": "Agent Overrides",
+          "description": "Override settings for specific agents, e.g. to disable the agent, set a custom model config, or run config.",
+          "markdownDescription": "Override settings for specific agents, e.g. to disable the agent, set a custom model config, or run config.\n\n- Category: `Advanced`\n- Requires restart: `yes`\n- Default: `{}`",
+          "default": {},
+          "type": "object",
+          "additionalProperties": {
+            "$ref": "#/$defs/AgentOverride"
+          }
+        }
+      },
+      "additionalProperties": false
+    },
     "context": {
       "title": "Context",
       "description": "Settings for managing context provided to the model.",
@@ -1854,6 +1874,36 @@
         }
       }
     },
+    "AgentOverride": {
+      "type": "object",
+      "description": "Override settings for a specific agent.",
+      "additionalProperties": false,
+      "properties": {
+        "modelConfig": {
+          "type": "object",
+          "additionalProperties": true
+        },
+        "runConfig": {
+          "type": "object",
+          "description": "Run configuration for an agent.",
+          "additionalProperties": false,
+          "properties": {
+            "maxTimeMinutes": {
+              "type": "number",
+              "description": "The maximum execution time for the agent in minutes."
+            },
+            "maxTurns": {
+              "type": "number",
+              "description": "The maximum number of conversational turns."
+            }
+          }
+        },
+        "disabled": {
+          "type": "boolean",
+          "description": "Whether to disable the agent."
+        }
+      }
+    },
     "CustomTheme": {
       "type": "object",
       "description": "Custom theme definition used for styling Gemini CLI output. Colors are provided as hex strings or named ANSI colors.",