diff --git a/src/vs/platform/agentHost/node/agentService.ts b/src/vs/platform/agentHost/node/agentService.ts
index 50a79dfa965..b90fa91c0c0 100644
--- a/src/vs/platform/agentHost/node/agentService.ts
+++ b/src/vs/platform/agentHost/node/agentService.ts
@@ -172,7 +172,6 @@ export class AgentService extends Disposable implements IAgentService {
 			this._sessionToProvider.delete(session.toString());
 		}
 		this._stateManager.deleteSession(session.toString());
-		this._sessionDataService.deleteSessionData(session);
 	}
 
 	// ---- Protocol methods ---------------------------------------------------
diff --git a/src/vs/platform/agentHost/node/agentSideEffects.ts b/src/vs/platform/agentHost/node/agentSideEffects.ts
index 64132425be3..fa90488d644 100644
--- a/src/vs/platform/agentHost/node/agentSideEffects.ts
+++ b/src/vs/platform/agentHost/node/agentSideEffects.ts
@@ -341,7 +341,6 @@ export class AgentSideEffects extends Disposable implements IProtocolSideEffectH
 		const agent = this._options.getAgent(session);
 		agent?.disposeSession(URI.parse(session)).catch(() => { });
 		this._stateManager.deleteSession(session);
-		this._options.sessionDataService.deleteSessionData(URI.parse(session));
 	}
 
 	async handleListSessions(): Promise<ISessionSummary[]> {
diff --git a/src/vs/platform/agentHost/node/copilot/fileEditTracker.ts b/src/vs/platform/agentHost/node/copilot/fileEditTracker.ts
index d6aa590242f..7eee79b096e 100644
--- a/src/vs/platform/agentHost/node/copilot/fileEditTracker.ts
+++ b/src/vs/platform/agentHost/node/copilot/fileEditTracker.ts
@@ -45,12 +45,16 @@ export function parseSessionDbUri(raw: string): ISessionDbUriFields | undefined
 	if (!toolCallId || !filePath || (part !== 'before' && part !== 'after')) {
 		return undefined;
 	}
-	return {
-		sessionUri: decodeHex(parsed.authority).toString(),
-		toolCallId: decodeURIComponent(toolCallId),
-		filePath: decodeHex(filePath).toString(),
-		part
-	};
+	try {
+		return {
+			sessionUri: decodeHex(parsed.authority).toString(),
+			toolCallId: decodeURIComponent(toolCallId),
+			filePath: decodeHex(filePath).toString(),
+			part
+		};
+	} catch {
+		return undefined;
+	}
 }
 
 /**
diff --git a/src/vs/platform/agentHost/node/copilot/mapSessionEvents.ts b/src/vs/platform/agentHost/node/copilot/mapSessionEvents.ts
index 56c9a09e79a..6f697f02cae 100644
--- a/src/vs/platform/agentHost/node/copilot/mapSessionEvents.ts
+++ b/src/vs/platform/agentHost/node/copilot/mapSessionEvents.ts
@@ -115,7 +115,7 @@ export async function mapSessionEvents(
 					list.push(r);
 				}
 			}
-		} catch {
+		} catch (_e) {
 			// Database may not exist yet for new sessions — that's fine
 		}
 	}
diff --git a/src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/stateToProgressAdapter.ts b/src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/stateToProgressAdapter.ts
index dceeac89e09..5a3e30493f8 100644
--- a/src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/stateToProgressAdapter.ts
+++ b/src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/stateToProgressAdapter.ts
@@ -4,7 +4,6 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { IMarkdownString, MarkdownString } from '../../../../../../base/common/htmlContent.js';
-import { generateUuid } from '../../../../../../base/common/uuid.js';
 import { URI } from '../../../../../../base/common/uri.js';
 import { ToolCallStatus, TurnState, ResponsePartKind, getToolFileEdits, getToolOutputText, type ICompletedToolCall, type IToolCallState, type ITurn } from '../../../../../../platform/agentHost/common/state/sessionState.js';
 import { getToolKind, getToolLanguage } from '../../../../../../platform/agentHost/common/state/sessionReducers.js';
@@ -46,12 +45,20 @@ export function turnsToHistory(turns: readonly ITurn[], participantId: string):
 			switch (rp.kind) {
 				case ResponsePartKind.Markdown:
 					if (rp.content) {
-						parts.push({ kind: 'markdownContent', content: new MarkdownString(rp.content) });
+						parts.push({ kind: 'markdownContent', content: new MarkdownString(rp.content, { supportHtml: true }) });
 					}
 					break;
-				case ResponsePartKind.ToolCall:
-					parts.push(completedToolCallToSerialized(rp.toolCall as ICompletedToolCall));
+				case ResponsePartKind.ToolCall: {
+					const tc = rp.toolCall as ICompletedToolCall;
+					const fileEditParts = completedToolCallToEditParts(tc);
+					const serialized = completedToolCallToSerialized(tc);
+					if (fileEditParts.length > 0) {
+						serialized.presentation = ToolInvocationPresentation.Hidden;
+					}
+					parts.push(serialized);
+					parts.push(...fileEditParts);
 					break;
+				}
 				case ResponsePartKind.Reasoning:
 					if (rp.content) {
 						parts.push({ kind: 'thinking', value: rp.content });
@@ -122,6 +129,35 @@ function completedToolCallToSerialized(tc: ICompletedToolCall): IChatToolInvocat
 	};
 }
 
+/**
+ * Builds edit-structure progress parts for a completed tool call that
+ * produced file edits. Returns an empty array if the tool call has no edits.
+ * These parts replay the undo stops and code-block UI when restoring history.
+ */
+function completedToolCallToEditParts(tc: ICompletedToolCall): IChatProgress[] {
+	if (tc.status !== ToolCallStatus.Completed) {
+		return [];
+	}
+	const fileEdits = getToolFileEdits(tc);
+	if (fileEdits.length === 0) {
+		return [];
+	}
+	const filePath = getFilePathFromToolInput(tc);
+	if (!filePath) {
+		return [];
+	}
+	const fileUri = URI.file(filePath);
+	const parts: IChatProgress[] = [];
+	for (const _edit of fileEdits) {
+		parts.push({ kind: 'markdownContent', content: new MarkdownString('\n````\n') });
+		parts.push({ kind: 'codeblockUri', uri: fileUri, isEdit: true, undoStopId: tc.toolCallId });
+		parts.push({ kind: 'textEdit', uri: fileUri, edits: [], done: false, isExternalEdit: true });
+		parts.push({ kind: 'textEdit', uri: fileUri, edits: [], done: true, isExternalEdit: true });
+		parts.push({ kind: 'markdownContent', content: new MarkdownString('\n````\n') });
+	}
+	return parts;
+}
+
 /**
  * Creates a live {@link ChatToolInvocation} from the protocol's tool-call
  * state. Used during active turns to represent running tool calls in the UI.
@@ -278,7 +314,7 @@ function fileEditsToExternalEdits(tc: IToolCallState): IToolCallFileEdit[] {
 				resource: URI.file(filePath),
 				beforeContentUri: URI.parse(edit.beforeURI),
 				afterContentUri: URI.parse(edit.afterURI),
-				undoStopId: generateUuid(),
+				undoStopId: tc.toolCallId,
 			});
 		}
 	}