Fix edit tools for headless tool invocation (scenario automation)

Edit tools (apply_patch, create_file, replace_string) fail when invoked
via vscode.lm.invokeTool() outside a chat participant context because
resolveInput() is never called and this._promptContext?.stream is undefined.

This unblocks the vscode-copilot-evaluation tool call service mode where an
external process invokes tools via HTTP without a VS Code chat session.

For each tool, when no chat response stream is available (!hasStream):
- apply_patch: Apply the already-built WorkspaceEdit directly via
  workspaceService.applyEdit() instead of streaming through responseStream
- create_file: Write file directly via fileSystemService.writeFile()
- replace_string: Build a WorkspaceEdit from the generated text edits
  and apply directly

The existing stream-based code path is completely unchanged. The !hasStream
branches return early before any stream code is reached.

Fixes microsoft/vscode-copilot-evaluation#2818

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: rwoll

package-lock.json

@@ -10,6 +10,7 @@ import { NotebookDocumentSnapshot } from '../../../platform/editing/common/noteb
 import { TextDocumentSnapshot } from '../../../platform/editing/common/textDocumentSnapshot';
 import { modelShouldUseReplaceStringHealing } from '../../../platform/endpoint/common/chatModelCapabilities';
 import { IEndpointProvider } from '../../../platform/endpoint/common/endpointProvider';
+import { isScenarioAutomation } from '../../../platform/env/common/envService';
 import { IFileSystemService } from '../../../platform/filesystem/common/fileSystemService';
 import { ILanguageDiagnosticsService } from '../../../platform/languages/common/languageDiagnosticsService';
 import { ILogService } from '../../../platform/log/common/logService';
@@ -28,7 +29,7 @@ import { extUriBiasedIgnorePathCase } from '../../../util/vs/base/common/resourc
 import { isDefined } from '../../../util/vs/base/common/types';
 import { URI } from '../../../util/vs/base/common/uri';
 import { IInstantiationService } from '../../../util/vs/platform/instantiation/common/instantiation';
-import { ChatRequestEditorData, ChatResponseTextEditPart, EndOfLine, ExtendedLanguageModelToolResult, Position as ExtPosition, LanguageModelPromptTsxPart, LanguageModelToolResult, TextEdit } from '../../../vscodeTypes';
+import { ChatRequestEditorData, ChatResponseTextEditPart, EndOfLine, ExtendedLanguageModelToolResult, Position as ExtPosition, LanguageModelPromptTsxPart, LanguageModelToolResult, TextEdit, WorkspaceEdit } from '../../../vscodeTypes';
 import { IBuildPromptContext } from '../../prompt/common/intents';
 import { renderPromptElementJSON } from '../../prompts/node/base/promptRenderer';
 import { CellOrNotebookEdit, processFullRewriteNotebookEdits } from '../../prompts/node/codeMapper/codeMapper';
@@ -173,7 +174,7 @@ export abstract class AbstractReplaceStringTool<T extends { explanation: string
 		}
 
 		// Validate parameters
-		if (!input.filePath || input.oldString === undefined || input.newString === undefined || !this._promptContext) {
+		if (!input.filePath || input.oldString === undefined || input.newString === undefined || (!this._promptContext && !isScenarioAutomation)) {
 			this.sendReplaceTelemetry('invalidStrings', options, input, undefined, undefined, undefined);
 			throw new Error('Invalid input');
 		}
@@ -207,12 +208,12 @@ export abstract class AbstractReplaceStringTool<T extends { explanation: string
 				const model = await this.modelForTelemetry(options);
 				const telemetryOptions: NotebookEditGenerationTelemtryOptions = {
 					model,
-					requestId: this._promptContext.requestId,
+					requestId: this._promptContext?.requestId,
 					source: NotebookEditGenrationSource.stringReplace,
 				};
 
 				notebookEdits = await Iterable.asyncToArray(processFullRewriteNotebookEdits(document.document, updatedFile, this.alternativeNotebookEditGenerator, telemetryOptions, token));
-				sendEditNotebookTelemetry(this.telemetryService, this.endpointProvider, 'stringReplace', document.uri, this._promptContext.requestId, model || 'unknown');
+				sendEditNotebookTelemetry(this.telemetryService, this.endpointProvider, 'stringReplace', document.uri, this._promptContext?.requestId, model || 'unknown');
 				updated = NotebookDocumentSnapshot.fromNewText(updatedFile, document);
 			} else {
 				updated = TextDocumentSnapshot.fromNewText(updatedFile, document);
@@ -255,12 +256,67 @@ export abstract class AbstractReplaceStringTool<T extends { explanation: string
 	}
 
 	protected async applyAllEdits(options: vscode.LanguageModelToolInvocationOptions<T>, edits: IPrepareEdit[], token: vscode.CancellationToken) {
-		if (!this._promptContext?.stream) {
+		const hasStream = !!this._promptContext?.stream;
+		if (!hasStream && !isScenarioAutomation) {
 			throw new Error('no prompt context found');
 		}
 
 		logEditToolResult(this.logService, options.chatRequestId, ...edits.map(e => ({ input: e.input, success: e.generatedEdit.success, healed: e.healed })));
 
+		// Scenario automation / headless mode: apply edits directly without streaming
+		if (!hasStream) {
+			const fileResults: IEditedFile[] = [];
+			const workspaceEdit = new WorkspaceEdit();
+
+			for (const { document, uri, generatedEdit, healed } of edits) {
+				const isNotebook = this.notebookService.hasSupportedNotebooks(uri);
+				const existingDiagnostics = document ? this.languageDiagnosticsService.getDiagnostics(document.uri) : [];
+
+				if (!generatedEdit.success) {
+					fileResults.push({ operation: ActionType.UPDATE, uri, isNotebook, existingDiagnostics, error: generatedEdit.errorMessage });
+					continue;
+				}
+
+				if (generatedEdit.textEdits) {
+					for (const edit of generatedEdit.textEdits) {
+						workspaceEdit.replace(uri, edit.range, edit.newText);
+					}
+				}
+
+				fileResults.push({
+					operation: ActionType.UPDATE,
+					uri,
+					isNotebook,
+					existingDiagnostics,
+					healed: healed ? JSON.stringify({ oldString: healed.oldString, newString: healed.newString }, null, 2) : undefined
+				});
+			}
+
+			await this.workspaceService.applyEdit(workspaceEdit);
+
+			const result = new ExtendedLanguageModelToolResult([
+				new LanguageModelPromptTsxPart(
+					await renderPromptElementJSON(
+						this.instantiationService,
+						EditFileResult,
+						{ files: fileResults, diagnosticsTimeout: 2000, toolName: this.toolName(), requestId: options.chatRequestId, model: options.model },
+						options.tokenizationOptions ?? {
+							tokenBudget: 5000,
+							countTokens: (t) => Promise.resolve(t.length * 3 / 4)
+						},
+						token,
+					),
+				)
+			]);
+			result.hasError = fileResults.some(f => f.error);
+			return result;
+		}
+
+		// Stream path: _promptContext is guaranteed to exist since hasStream is true
+		if (!this._promptContext?.stream) {
+			throw new Error('no prompt context found');
+		}
+
 		const fileResults: IEditedFile[] = [];
 		const existingDiagnosticMap = new ResourceMap<vscode.Diagnostic[]>();