diff --git a/packages/pi-coding-agent/src/modes/rpc/rpc-client.ts b/packages/pi-coding-agent/src/modes/rpc/rpc-client.ts
index 197dee8a0..e776bd8ad 100644
--- a/packages/pi-coding-agent/src/modes/rpc/rpc-client.ts
+++ b/packages/pi-coding-agent/src/modes/rpc/rpc-client.ts
@@ -11,7 +11,7 @@ import type { SessionStats } from "../../core/agent-session.js";
 import type { BashResult } from "../../core/bash-executor.js";
 import type { CompactionResult } from "../../core/compaction/index.js";
 import { attachJsonlLineReader, serializeJsonLine } from "./jsonl.js";
-import type { RpcCommand, RpcResponse, RpcSessionState, RpcSlashCommand } from "./rpc-types.js";
+import type { RpcCommand, RpcInitResult, RpcResponse, RpcSessionState, RpcSlashCommand } from "./rpc-types.js";
 
 // ============================================================================
 // Types
@@ -413,6 +413,44 @@ export class RpcClient {
 		}));
 	}
 
+	/**
+	 * Initialize a v2 protocol session. Must be sent as the first command.
+	 * Returns the negotiated protocol version, session ID, and server capabilities.
+	 */
+	async init(options?: { clientId?: string }): Promise<RpcInitResult> {
+		const response = await this.send({ type: "init", protocolVersion: 2, clientId: options?.clientId });
+		return this.getData<RpcInitResult>(response);
+	}
+
+	/**
+	 * Request a graceful shutdown of the agent process.
+	 * Waits for the response before the process exits.
+	 */
+	async shutdown(): Promise<void> {
+		await this.send({ type: "shutdown" });
+		// Wait for process to exit after shutdown acknowledgment
+		if (this.process) {
+			await new Promise<void>((resolve) => {
+				const timeout = setTimeout(() => {
+					this.process?.kill("SIGKILL");
+					resolve();
+				}, 5000);
+				this.process?.on("exit", () => {
+					clearTimeout(timeout);
+					resolve();
+				});
+			});
+		}
+	}
+
+	/**
+	 * Subscribe to specific event types (v2 only).
+	 * Pass ["*"] to receive all events, or a list of event type strings to filter.
+	 */
+	async subscribe(events: string[]): Promise<void> {
+		await this.send({ type: "subscribe", events });
+	}
+
 	// =========================================================================
 	// Helpers
 	// =========================================================================
diff --git a/packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts b/packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts
index 27a898765..f2f8fbe4c 100644
--- a/packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts
+++ b/packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts
@@ -82,6 +82,12 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 	let protocolVersion: 1 | 2 = 1;
 	let protocolLocked = false;
 
+	// v2 runId threading: tracks the current execution run
+	let currentRunId: string | null = null;
+
+	// v2 event filtering: null = no filter (all events); Set = only listed event types
+	let eventFilter: Set<string> | null = null;
+
 	const embeddedTerminalEnabled = process.env.GSD_WEB_BRIDGE_TUI === "1";
 	const remoteTerminal = embeddedTerminalEnabled
 		? new RemoteTerminal({
@@ -433,7 +439,55 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 
 	// Output all agent events as JSON
 	const unsubscribe = session.subscribe((event) => {
-		output(event);
+		// v2: emit synthesized events before the regular event
+		if (protocolVersion === 2) {
+			// cost_update on assistant message_end
+			if (event.type === "message_end" && event.message.role === "assistant" && currentRunId) {
+				const stats = session.getSessionStats();
+				const costUpdate = {
+					type: "cost_update" as const,
+					runId: currentRunId,
+					turnCost: session.getLastTurnCost(),
+					cumulativeCost: stats.cost,
+					tokens: {
+						input: stats.tokens.input,
+						output: stats.tokens.output,
+						cacheRead: stats.tokens.cacheRead,
+						cacheWrite: stats.tokens.cacheWrite,
+					},
+				};
+				if (!eventFilter || eventFilter.has("cost_update")) {
+					output(costUpdate);
+				}
+			}
+
+			// execution_complete on agent_end
+			if (event.type === "agent_end" && currentRunId) {
+				const stats = session.getSessionStats();
+				const completionEvent = {
+					type: "execution_complete" as const,
+					runId: currentRunId,
+					status: "completed" as const,
+					stats,
+				};
+				if (!eventFilter || eventFilter.has("execution_complete")) {
+					output(completionEvent);
+				}
+				currentRunId = null;
+			}
+		}
+
+		// Apply event filter (v2 only, applies to agent session events only)
+		if (protocolVersion === 2 && eventFilter && !eventFilter.has(event.type)) {
+			return;
+		}
+
+		// Emit the regular event, with runId injection in v2 mode
+		if (protocolVersion === 2 && currentRunId) {
+			output({ ...event, runId: currentRunId });
+		} else {
+			output(event);
+		}
 	});
 
 	// Handle a single command
@@ -446,6 +500,9 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 			// =================================================================
 
 			case "prompt": {
+				// v2: generate runId for execution tracking
+				const runId = protocolVersion === 2 ? crypto.randomUUID() : undefined;
+				if (runId) currentRunId = runId;
 				// Don't await - events will stream
 				// Extension commands are executed immediately, file prompt templates are expanded
 				// If streaming and streamingBehavior specified, queues via steer/followUp
@@ -456,17 +513,23 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 						source: "rpc",
 					})
 					.catch((e) => output(error(id, "prompt", e.message)));
-				return success(id, "prompt");
+				return { id, type: "response", command: "prompt", success: true, ...(runId && { runId }) } as RpcResponse;
 			}
 
 			case "steer": {
+				// v2: generate runId for execution tracking
+				const runId = protocolVersion === 2 ? crypto.randomUUID() : undefined;
+				if (runId) currentRunId = runId;
 				await session.steer(command.message, command.images);
-				return success(id, "steer");
+				return { id, type: "response", command: "steer", success: true, ...(runId && { runId }) } as RpcResponse;
 			}
 
 			case "follow_up": {
+				// v2: generate runId for execution tracking
+				const runId = protocolVersion === 2 ? crypto.randomUUID() : undefined;
+				if (runId) currentRunId = runId;
 				await session.followUp(command.message, command.images);
-				return success(id, "follow_up");
+				return { id, type: "response", command: "follow_up", success: true, ...(runId && { runId }) } as RpcResponse;
 			}
 
 			case "abort": {
@@ -717,6 +780,19 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 				return success(id, "terminal_redraw");
 			}
 
+			// =================================================================
+			// v2 Protocol: subscribe
+			// =================================================================
+
+			case "subscribe": {
+				if (command.events.includes("*")) {
+					eventFilter = null; // wildcard = all events
+				} else {
+					eventFilter = new Set(command.events);
+				}
+				return success(id, "subscribe");
+			}
+
 			// =================================================================
 			// v2 Protocol: shutdown
 			// =================================================================
diff --git a/packages/pi-coding-agent/src/modes/rpc/rpc-types.ts b/packages/pi-coding-agent/src/modes/rpc/rpc-types.ts
index 957e0f3ac..20d5c2c73 100644
--- a/packages/pi-coding-agent/src/modes/rpc/rpc-types.ts
+++ b/packages/pi-coding-agent/src/modes/rpc/rpc-types.ts
@@ -231,6 +231,7 @@ export type RpcResponse =
 	// v2 Protocol
 	| { id?: string; type: "response"; command: "init"; success: true; data: RpcInitResult }
 	| { id?: string; type: "response"; command: "shutdown"; success: true }
+	| { id?: string; type: "response"; command: "subscribe"; success: true }
 
 	// Error response (any command can fail)
 	| { id?: string; type: "response"; command: string; success: false; error: string };