update Claude-*-4.5 default prompt (#1665)

Author: bhavyaus

package.json

@@ -3106,14 +3106,6 @@
 						],
 						"description": "%github.copilot.config.grokCodeAlternatePrompt%"
 					},
-					"github.copilot.chat.claudeSonnet45AlternatePrompt": {
-						"type": "string",
-						"default": "default",
-						"tags": [
-							"experimental"
-						],
-						"description": "%github.copilot.config.claudeSonnet45AlternatePrompt%"
-					},
 					"github.copilot.chat.useResponsesApi": {
 						"type": "boolean",
 						"default": true,

package.nls.json

@@ -184,7 +184,6 @@
 	"github.copilot.config.gpt5AlternatePrompt": "Specifies an experimental alternate prompt to use for GPT-5 models.",
 	"github.copilot.config.gpt5CodexAlternatePrompt": "Specifies an experimental alternate prompt to use for the GPT-5-Codex model.",
 	"github.copilot.config.grokCodeAlternatePrompt": "Specifies an experimental alternate prompt to use for Grok Code models.",
-	"github.copilot.config.claudeSonnet45AlternatePrompt": "Specifies an experimental alternate prompt to use for Claude Sonnet 4.5.",
 	"github.copilot.command.fixTestFailure": "Fix Test Failure",
 	"copilot.description": "Ask or edit in context",
 	"copilot.edits.description": "Edit files in your workspace",

src/extension/prompts/node/agent/anthropicPrompts.tsx

@@ -4,9 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { PromptElement, PromptSizing } from '@vscode/prompt-tsx';
-import { ConfigKey, IConfigurationService } from '../../../../platform/configuration/common/configurationService';
 import { IChatEndpoint } from '../../../../platform/networking/common/networking';
-import { IExperimentationService } from '../../../../platform/telemetry/common/nullExperimentationService';
 import { ToolName } from '../../../tools/common/toolNames';
 import { InstructionMessage } from '../base/instructionMessage';
 import { ResponseTranslationRules } from '../base/responseTranslationRules';
@@ -113,7 +111,7 @@ class DefaultAnthropicAgentPrompt extends PromptElement<DefaultAgentPromptProps>
 	}
 }
 
-class ClaudeSonnet45PromptV2 extends PromptElement<DefaultAgentPromptProps> {
+class Claude45DefaultPrompt extends PromptElement<DefaultAgentPromptProps> {
 	async render(state: void, sizing: PromptSizing) {
 		const tools = detectToolCapabilities(this.props.availableTools);
 
@@ -210,24 +208,13 @@ class ClaudeSonnet45PromptV2 extends PromptElement<DefaultAgentPromptProps> {
 }
 
 class AnthropicPromptResolver implements IAgentPrompt {
-	constructor(
-		@IConfigurationService private readonly configurationService: IConfigurationService,
-		@IExperimentationService private readonly experimentationService: IExperimentationService,
-	) { }
-
 	static readonly familyPrefixes = ['claude', 'Anthropic'];
 
 	resolvePrompt(endpoint: IChatEndpoint): PromptConstructor | undefined {
 
 		if (endpoint.model?.startsWith('claude-sonnet-4.5') ||
 			endpoint.model?.startsWith('claude-haiku-4.5')) {
-			const promptType = this.configurationService.getExperimentBasedConfig(
-				ConfigKey.ClaudeSonnet45AlternatePrompt,
-				this.experimentationService);
-
-			if (promptType === 'v2') {
-				return ClaudeSonnet45PromptV2;
-			}
+			return Claude45DefaultPrompt;
 		}
 		return DefaultAnthropicAgentPrompt;
 	}