diff --git a/src/vs/workbench/contrib/chat/browser/chat.contribution.ts b/src/vs/workbench/contrib/chat/browser/chat.contribution.ts
index 3b3eb37244117..90f04193d5d3e 100644
--- a/src/vs/workbench/contrib/chat/browser/chat.contribution.ts
+++ b/src/vs/workbench/contrib/chat/browser/chat.contribution.ts
@@ -594,12 +594,6 @@ configurationRegistry.registerConfiguration({
 				}
 			}
 		},
-		[ChatConfiguration.ImplementationAgentModel]: {
-			type: 'string',
-			description: nls.localize('chat.implementationAgentModel', "Specifies the model to use when switching to an 'implement' agent following Plan mode. When set, this model will be automatically selected instead of the user's current model selection."),
-			default: '',
-			tags: ['experimental'],
-		},
 		[ChatConfiguration.EditModeHidden]: {
 			type: 'boolean',
 			description: nls.localize('chat.editMode.hidden', "When enabled, hides the Edit mode from the chat mode picker."),
diff --git a/src/vs/workbench/contrib/chat/browser/widget/input/chatInputPart.ts b/src/vs/workbench/contrib/chat/browser/widget/input/chatInputPart.ts
index d5b72e8001907..44e4dfcd8543e 100644
--- a/src/vs/workbench/contrib/chat/browser/widget/input/chatInputPart.ts
+++ b/src/vs/workbench/contrib/chat/browser/widget/input/chatInputPart.ts
@@ -63,7 +63,6 @@ import { IInstantiationService } from '../../../../../../platform/instantiation/
 import { ServiceCollection } from '../../../../../../platform/instantiation/common/serviceCollection.js';
 import { IKeybindingService } from '../../../../../../platform/keybinding/common/keybinding.js';
 import { ILabelService } from '../../../../../../platform/label/common/label.js';
-import { IProductService } from '../../../../../../platform/product/common/productService.js';
 import { WorkbenchList } from '../../../../../../platform/list/browser/listService.js';
 import { ILogService } from '../../../../../../platform/log/common/log.js';
 import { ObservableMemento, observableMemento } from '../../../../../../platform/observable/common/observableMemento.js';
@@ -119,7 +118,7 @@ import { IChatInputPickerOptions } from './chatInputPickerActionItem.js';
 import { ChatSelectedTools } from './chatSelectedTools.js';
 import { DelegationSessionPickerActionItem } from './delegationSessionPickerActionItem.js';
 import { IModelPickerDelegate, ModelPickerActionItem } from './modelPickerActionItem.js';
-import { IModePickerDelegate, isBuiltinImplementMode, ModePickerActionItem } from './modePickerActionItem.js';
+import { IModePickerDelegate, ModePickerActionItem } from './modePickerActionItem.js';
 import { SessionTypePickerActionItem } from './sessionTargetPickerActionItem.js';
 import { WorkspacePickerActionItem } from './workspacePickerActionItem.js';
 
@@ -476,7 +475,6 @@ export class ChatInputPart extends Disposable implements IHistoryNavigationWidge
 		@IChatContextService private readonly chatContextService: IChatContextService,
 		@IAgentSessionsService private readonly agentSessionsService: IAgentSessionsService,
 		@IWorkspaceContextService private readonly workspaceContextService: IWorkspaceContextService,
-		@IProductService private readonly productService: IProductService,
 	) {
 		super();
 
@@ -629,19 +627,6 @@ export class ChatInputPart extends Disposable implements IHistoryNavigationWidge
 			const model = mode.model?.read(r);
 			if (model) {
 				this.switchModelByQualifiedName(model);
-			} else {
-				// Check for implementation agent model override setting
-				if (isBuiltinImplementMode(mode, this.productService)) {
-					const implementModel = this.configurationService.getValue<string>(ChatConfiguration.ImplementationAgentModel);
-					if (implementModel && implementModel.length > 0) {
-						const success = this.switchModelByQualifiedName(implementModel);
-						if (success) {
-							this.logService.debug(`[ChatInputPart] Applied chat.implementationAgentModel setting: '${implementModel}'`);
-						} else {
-							this.logService.warn(`chat.implementationAgentModel setting value '${implementModel}' did not match any available model. Defaulting to currently selected model.`);
-						}
-					}
-				}
 			}
 		}));
 
@@ -744,6 +729,7 @@ export class ChatInputPart extends Disposable implements IHistoryNavigationWidge
 			this.setCurrentLanguageModel(model);
 			return true;
 		}
+		this.logService.warn(`[chat] Model "${qualifiedModelName}" not found. Use format "<name> (<vendor>)", e.g. "GPT-4o (copilot)".`);
 		return false;
 	}
 
diff --git a/src/vs/workbench/contrib/chat/common/constants.ts b/src/vs/workbench/contrib/chat/common/constants.ts
index a455804b70f65..96a228beb72d5 100644
--- a/src/vs/workbench/contrib/chat/common/constants.ts
+++ b/src/vs/workbench/contrib/chat/common/constants.ts
@@ -43,7 +43,6 @@ export enum ChatConfiguration {
 	ExitAfterDelegation = 'chat.exitAfterDelegation',
 	CommandCenterTriStateToggle = 'chat.commandCenter.triStateToggle',
 	ExplainChangesEnabled = 'chat.editing.explainChanges.enabled',
-	ImplementationAgentModel = 'chat.implementationAgentModel',
 }
 
 /**