feat(coding-agent): add messageId and timestamp to markdown transformer context

* feat(coding-agent): add messageId and timestamp to markdown transformer context

* fix(coding-agent): update compaction render test for messageMeta argument

---------

Co-authored-by: Petr Houška <houskape@gmail.com>

packages/coding-agent/src/core/extensions/types.ts

@@ -1542,6 +1542,10 @@ export interface MarkdownTransformContext {
 	messageType: "user" | "assistant" | "assistant-thinking";
 	isStreaming: boolean;
 	availableWidth: number;
+	/** Persisted session-entry id. Undefined for live messages or live rendering; available when rendering from persisted session entries. */
+	messageId?: string;
+	/** Persisted session-entry ISO timestamp. Undefined for live messages or live rendering; available when rendering from persisted session entries. */
+	timestamp?: string;
 }
 
 export type MarkdownTransformer = (markdown: string, context: MarkdownTransformContext) => string;

packages/coding-agent/src/modes/interactive/components/assistant-message.ts

@@ -21,6 +21,8 @@ export class AssistantMessageComponent extends Container {
 	private lastMessage?: AssistantMessage;
 	private hasToolCalls = false;
 	private isStreaming = false;
+	private messageId?: string;
+	private timestamp?: string;
 	private thinkingVisibilityOverrides = new Map<number, boolean>();
 
 	constructor(
@@ -30,6 +32,8 @@ export class AssistantMessageComponent extends Container {
 		hiddenThinkingLabel = "Thinking...",
 		outputPad = 1,
 		markdownTransformers: readonly MarkdownTransformer[] = [],
+		messageId?: string,
+		timestamp?: string,
 	) {
 		super();
 
@@ -38,6 +42,8 @@ export class AssistantMessageComponent extends Container {
 		this.hiddenThinkingLabel = hiddenThinkingLabel;
 		this.outputPad = outputPad;
 		this.markdownTransformers = markdownTransformers;
+		this.messageId = messageId;
+		this.timestamp = timestamp;
 
 		// Container for text/thinking content
 		this.contentContainer = new Container();
@@ -112,7 +118,13 @@ export class AssistantMessageComponent extends Container {
 				// Set paddingY=0 to avoid extra spacing before tool executions
 				this.contentContainer.addChild(
 					new Markdown(content.text.trim(), this.outputPad, 0, this.markdownTheme, undefined, {
-						transform: createMarkdownTransform("assistant", this.isStreaming, this.markdownTransformers),
+						transform: createMarkdownTransform(
+							"assistant",
+							this.isStreaming,
+							this.markdownTransformers,
+							this.messageId,
+							this.timestamp,
+						),
 					}),
 				);
 			} else if (content.type === "thinking") {
@@ -157,6 +169,8 @@ export class AssistantMessageComponent extends Container {
 									"assistant-thinking",
 									this.isStreaming,
 									this.markdownTransformers,
+									this.messageId,
+									this.timestamp,
 								),
 							},
 						);

packages/coding-agent/src/modes/interactive/components/markdown-transform.ts

@@ -4,9 +4,15 @@ export function createMarkdownTransform(
 	messageType: MarkdownTransformContext["messageType"],
 	isStreaming: boolean,
 	transformers: readonly MarkdownTransformer[],
+	messageId?: string,
+	timestamp?: string,
 ): (markdown: string, availableWidth: number) => string {
 	return (markdown, availableWidth) =>
-		applyMarkdownTransformers(markdown, { messageType, isStreaming, availableWidth }, transformers);
+		applyMarkdownTransformers(
+			markdown,
+			{ messageType, isStreaming, availableWidth, messageId, timestamp },
+			transformers,
+		);
 }
 
 function applyMarkdownTransformers(

packages/coding-agent/src/modes/interactive/components/user-message.ts

@@ -15,18 +15,24 @@ export class UserMessageComponent extends Container {
 	private markdownTheme: MarkdownTheme;
 	private outputPad: number;
 	private markdownTransformers: readonly MarkdownTransformer[];
+	private messageId?: string;
+	private timestamp?: string;
 
 	constructor(
 		text: string,
 		markdownTheme: MarkdownTheme = getMarkdownTheme(),
 		outputPad = 1,
 		markdownTransformers: readonly MarkdownTransformer[] = [],
+		messageId?: string,
+		timestamp?: string,
 	) {
 		super();
 		this.text = text;
 		this.markdownTheme = markdownTheme;
 		this.outputPad = outputPad;
 		this.markdownTransformers = markdownTransformers;
+		this.messageId = messageId;
+		this.timestamp = timestamp;
 		this.rebuild();
 	}
 
@@ -52,7 +58,13 @@ export class UserMessageComponent extends Container {
 				{
 					preserveOrderedListMarkers: true,
 					preserveBackslashEscapes: true,
-					transform: createMarkdownTransform("user", false, this.markdownTransformers),
+					transform: createMarkdownTransform(
+						"user",
+						false,
+						this.markdownTransformers,
+						this.messageId,
+						this.timestamp,
+					),
 				},
 			),
 		);

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -3834,7 +3834,10 @@ export class InteractiveMode {
 		this.chatContainer.addChild(component);
 	}
 
-	private addMessageToChat(message: AgentMessage, options?: { populateHistory?: boolean }): void {
+	private addMessageToChat(
+		message: AgentMessage,
+		options?: { populateHistory?: boolean; messageId?: string; timestamp?: string },
+	): void {
 		switch (message.role) {
 			case "bashExecution": {
 				const component = new BashExecutionComponent(
@@ -3917,6 +3920,8 @@ export class InteractiveMode {
 								this.getMarkdownThemeWithSettings(),
 								this.outputPad,
 								this.getMarkdownTransformers(),
+								options?.messageId,
+								options?.timestamp,
 							);
 							this.chatContainer.addChild(userComponent);
 						}
@@ -3926,6 +3931,8 @@ export class InteractiveMode {
 							this.getMarkdownThemeWithSettings(),
 							this.outputPad,
 							this.getMarkdownTransformers(),
+							options?.messageId,
+							options?.timestamp,
 						);
 						this.chatContainer.addChild(userComponent);
 					}
@@ -3943,6 +3950,8 @@ export class InteractiveMode {
 					this.hiddenThinkingLabel,
 					this.outputPad,
 					this.getMarkdownTransformers(),
+					options?.messageId,
+					options?.timestamp,
 				);
 				this.chatContainer.addChild(assistantComponent);
 				break;
@@ -3959,6 +3968,7 @@ export class InteractiveMode {
 
 	private renderSessionItems(
 		items: readonly RenderSessionItem[],
+		messageMeta?: Map<AgentMessage, { id: string; timestamp: string }>,
 		options: { updateFooter?: boolean; populateHistory?: boolean } = {},
 	): void {
 		this.pendingTools.clear();
@@ -3991,7 +4001,11 @@ export class InteractiveMode {
 			const message = item;
 			// Assistant messages need special handling for tool calls
 			if (message.role === "assistant") {
-				this.addMessageToChat(message);
+				const meta = messageMeta?.get(message);
+				this.addMessageToChat(message, {
+					messageId: meta?.id,
+					timestamp: meta?.timestamp,
+				});
 				// Render tool call components
 				for (const content of message.content) {
 					if (content.type === "toolCall") {
@@ -4041,7 +4055,12 @@ export class InteractiveMode {
 				}
 			} else {
 				// All other messages use standard rendering
-				this.addMessageToChat(message, options);
+				const meta = messageMeta?.get(message);
+				this.addMessageToChat(message, {
+					...options,
+					messageId: meta?.id,
+					timestamp: meta?.timestamp,
+				});
 			}
 		}
 
@@ -4063,17 +4082,21 @@ export class InteractiveMode {
 	): void {
 		// Selection coordinates point into the transcript being replaced (#9311).
 		if (this.renderer instanceof TuiAltScreen) this.renderer.resetTextSelection();
+		const messageMeta = new Map<AgentMessage, { id: string; timestamp: string }>();
 		const items = entries.flatMap((entry): RenderSessionItem[] => {
 			if (entry.type === "custom" || (entry.type === "usage" && entry.kind === "cache_warm")) {
 				return [entry];
 			}
 			const messages = sessionEntryToContextMessages(entry);
+			for (const msg of messages) {
+				messageMeta.set(msg, { id: entry.id, timestamp: entry.timestamp });
+			}
 			if ((entry.type === "compaction" || entry.type === "branch_summary") && entry.usage && messages.length > 0) {
 				return [...messages, { type: "compaction_cost", kind: entry.type, usage: entry.usage }];
 			}
 			return messages;
 		});
-		this.renderSessionItems(items, options);
+		this.renderSessionItems(items, messageMeta, options);
 	}
 
 	private addCacheWarmingUsage(entry: UsageEntry): void {

packages/coding-agent/test/interactive-mode-compaction.test.ts

@@ -102,8 +102,15 @@ describe("InteractiveMode compaction events", () => {
 				expect.objectContaining({ role: "compactionSummary", summary: "previous summary" }),
 				{ type: "compaction_cost", kind: "compaction", usage: previousUsage },
 			],
+			expect.any(Map),
 			{},
 		);
+		const [items, messageMeta] = fakeThis.renderSessionItems.mock.calls[0] as [
+			unknown[],
+			Map<unknown, { id: string; timestamp: string }>,
+		];
+		expect(messageMeta.get(items[0])).toEqual({ id: "current", timestamp: "2025-01-02T00:00:00Z" });
+		expect(messageMeta.get(items[2])).toEqual({ id: "previous", timestamp: "2025-01-01T00:00:00Z" });
 	});
 
 	test("renders retained entries and appends the latest summary cost at the bottom", async () => {

packages/coding-agent/test/user-message.test.ts

@@ -55,4 +55,21 @@ describe("UserMessageComponent", () => {
 
 		expect(stripAnsi(component.render(80).join("\n"))).toContain("Message after");
 	});
+
+	test("passes persisted entry identity in transformer context; live leaves it undefined", () => {
+		initTheme("dark");
+		const captured: Array<{ messageId?: string; timestamp?: string }> = [];
+		const capture = (_markdown: string, context: { messageId?: string; timestamp?: string }) => {
+			captured.push({ messageId: context.messageId, timestamp: context.timestamp });
+			return _markdown;
+		};
+
+		new UserMessageComponent("restored", undefined, 1, [capture], "entry-abc", "2025-01-15T10:30:00.000Z").render(80);
+		new UserMessageComponent("live", undefined, 1, [capture]).render(80);
+
+		expect(captured).toEqual([
+			{ messageId: "entry-abc", timestamp: "2025-01-15T10:30:00.000Z" },
+			{ messageId: undefined, timestamp: undefined },
+		]);
+	});
 });