Support multiple messages in agent.prompt() and agentLoop

- agentLoop now accepts AgentMessage[] instead of single message
- agent.prompt() accepts AgentMessage | AgentMessage[]
- Emits message_start/end for each message in the array
- AgentSession.prompt() builds array with hook message + user message
- TUI now receives events for before_agent_start injected messages

packages/agent/src/agent-loop.ts

@@ -26,7 +26,7 @@ import type {
  * The prompt is added to the context and events are emitted for it.
  */
 export function agentLoop(
-	prompt: AgentMessage,
+	prompts: AgentMessage[],
 	context: AgentContext,
 	config: AgentLoopConfig,
 	signal?: AbortSignal,
@@ -35,16 +35,18 @@ export function agentLoop(
 	const stream = createAgentStream();
 
 	(async () => {
-		const newMessages: AgentMessage[] = [prompt];
+		const newMessages: AgentMessage[] = [...prompts];
 		const currentContext: AgentContext = {
 			...context,
-			messages: [...context.messages, prompt],
+			messages: [...context.messages, ...prompts],
 		};
 
 		stream.push({ type: "agent_start" });
 		stream.push({ type: "turn_start" });
-		stream.push({ type: "message_start", message: prompt });
-		stream.push({ type: "message_end", message: prompt });
+		for (const prompt of prompts) {
+			stream.push({ type: "message_start", message: prompt });
+			stream.push({ type: "message_end", message: prompt });
+		}
 
 		await runLoop(currentContext, newMessages, config, signal, stream, streamFn);
 	})();

packages/agent/src/agent.ts

@@ -168,29 +168,33 @@ export class Agent {
 	}
 
 	/** Send a prompt with an AgentMessage */
-	async prompt(message: AgentMessage): Promise<void>;
+	async prompt(message: AgentMessage | AgentMessage[]): Promise<void>;
 	async prompt(input: string, images?: ImageContent[]): Promise<void>;
-	async prompt(input: string | AgentMessage, images?: ImageContent[]) {
+	async prompt(input: string | AgentMessage | AgentMessage[], images?: ImageContent[]) {
 		const model = this._state.model;
 		if (!model) throw new Error("No model configured");
 
-		let userMessage: AgentMessage;
+		let msgs: AgentMessage[];
 
-		if (typeof input === "string") {
+		if (Array.isArray(input)) {
+			msgs = input;
+		} else if (typeof input === "string") {
 			const content: Array<TextContent | ImageContent> = [{ type: "text", text: input }];
 			if (images && images.length > 0) {
 				content.push(...images);
 			}
-			userMessage = {
-				role: "user",
-				content,
-				timestamp: Date.now(),
-			};
+			msgs = [
+				{
+					role: "user",
+					content,
+					timestamp: Date.now(),
+				},
+			];
 		} else {
-			userMessage = input;
+			msgs = [input];
 		}
 
-		await this._runLoop(userMessage);
+		await this._runLoop(msgs);
 	}
 
 	/** Continue from current context (for retry after overflow) */
@@ -208,10 +212,10 @@ export class Agent {
 
 	/**
 	 * Run the agent loop.
-	 * If userMessage is provided, starts a new conversation turn.
+	 * If messages are provided, starts a new conversation turn with those messages.
 	 * Otherwise, continues from existing context.
 	 */
-	private async _runLoop(userMessage?: AgentMessage) {
+	private async _runLoop(messages?: AgentMessage[]) {
 		const model = this._state.model;
 		if (!model) throw new Error("No model configured");
 
@@ -262,8 +266,8 @@ export class Agent {
 		let partial: AgentMessage | null = null;
 
 		try {
-			const stream = userMessage
-				? agentLoop(userMessage, context, config, this.abortController.signal, this.streamFn)
+			const stream = messages
+				? agentLoop(messages, context, config, this.abortController.signal, this.streamFn)
 				: agentLoopContinue(context, config, this.abortController.signal, this.streamFn);
 
 			for await (const event of stream) {

packages/agent/test/agent-loop.test.ts

@@ -105,7 +105,7 @@ describe("agentLoop with AgentMessage", () => {
 		};
 
 		const events: AgentEvent[] = [];
-		const stream = agentLoop(userPrompt, context, config, undefined, streamFn);
+		const stream = agentLoop([userPrompt], context, config, undefined, streamFn);
 
 		for await (const event of stream) {
 			events.push(event);
@@ -172,7 +172,7 @@ describe("agentLoop with AgentMessage", () => {
 		};
 
 		const events: AgentEvent[] = [];
-		const stream = agentLoop(userPrompt, context, config, undefined, streamFn);
+		const stream = agentLoop([userPrompt], context, config, undefined, streamFn);
 
 		for await (const event of stream) {
 			events.push(event);
@@ -224,7 +224,7 @@ describe("agentLoop with AgentMessage", () => {
 			return stream;
 		};
 
-		const stream = agentLoop(userPrompt, context, config, undefined, streamFn);
+		const stream = agentLoop([userPrompt], context, config, undefined, streamFn);
 
 		for await (const _ of stream) {
 			// consume
@@ -288,7 +288,7 @@ describe("agentLoop with AgentMessage", () => {
 		};
 
 		const events: AgentEvent[] = [];
-		const stream = agentLoop(userPrompt, context, config, undefined, streamFn);
+		const stream = agentLoop([userPrompt], context, config, undefined, streamFn);
 
 		for await (const event of stream) {
 			events.push(event);
@@ -351,7 +351,7 @@ describe("agentLoop with AgentMessage", () => {
 		};
 
 		const events: AgentEvent[] = [];
-		const stream = agentLoop(userPrompt, context, config, undefined, (_model, ctx, _options) => {
+		const stream = agentLoop([userPrompt], context, config, undefined, (_model, ctx, _options) => {
 			// Check if interrupt message is in context on second call
 			if (callIndex === 1) {
 				sawInterruptInContext = ctx.messages.some(

packages/coding-agent/src/core/agent-session.ts

@@ -490,30 +490,36 @@ export class AgentSession {
 		// Expand file-based slash commands if requested
 		const expandedText = expandCommands ? expandSlashCommand(text, [...this._fileCommands]) : text;
 
+		// Build messages array (hook message if any, then user message)
+		const messages: AgentMessage[] = [];
+
+		// Add user message
+		const userContent: (TextContent | ImageContent)[] = [{ type: "text", text: expandedText }];
+		if (options?.images) {
+			userContent.push(...options.images);
+		}
+		messages.push({
+			role: "user",
+			content: userContent,
+			timestamp: Date.now(),
+		});
+
 		// Emit before_agent_start hook event
 		if (this._hookRunner) {
 			const result = await this._hookRunner.emitBeforeAgentStart(expandedText, options?.images);
 			if (result?.message) {
-				// Append hook message to agent state and session
-				const hookMessage: HookMessage = {
+				messages.push({
 					role: "hookMessage",
 					customType: result.message.customType,
 					content: result.message.content,
 					display: result.message.display,
 					details: result.message.details,
 					timestamp: Date.now(),
-				};
-				this.agent.appendMessage(hookMessage);
-				this.sessionManager.appendCustomMessageEntry(
-					result.message.customType,
-					result.message.content,
-					result.message.display,
-					result.message.details,
-				);
+				});
 			}
 		}
 
-		await this.agent.prompt(expandedText, options?.images);
+		await this.agent.prompt(messages);
 		await this.waitForRetry();
 	}