diff --git a/engine/sdks/typescript/runner/src/mod.ts b/engine/sdks/typescript/runner/src/mod.ts
index c80a201649..0c1b33137d 100644
--- a/engine/sdks/typescript/runner/src/mod.ts
+++ b/engine/sdks/typescript/runner/src/mod.ts
@@ -2,6 +2,7 @@ import * as protocol from "@rivetkit/engine-runner-protocol";
 import type { Logger } from "pino";
 import type WebSocket from "ws";
 import { logger, setLogger } from "./log.js";
+import { stringifyCommandWrapper, stringifyEvent } from "./stringify";
 import { Tunnel } from "./tunnel";
 import {
 	calculateBackoff,
@@ -754,7 +755,7 @@ export class Runner {
 		for (const commandWrapper of commands) {
 			this.log?.info({
 				msg: "received command",
-				commandWrapper,
+				command: stringifyCommandWrapper(commandWrapper),
 			});
 			if (commandWrapper.inner.tag === "CommandStartActor") {
 				this.#handleCommandStartActor(commandWrapper);
@@ -905,9 +906,8 @@ export class Runner {
 
 		this.log?.info({
 			msg: "sending event to server",
-			index: eventWrapper.index,
-			tag: eventWrapper.inner.tag,
-			val: eventWrapper.inner.val,
+			event: stringifyEvent(eventWrapper.inner),
+			index: eventWrapper.index.toString(),
 		});
 
 		this.__sendToServer({
@@ -962,9 +962,8 @@ export class Runner {
 
 		this.log?.info({
 			msg: "sending event to server",
-			index: eventWrapper.index,
-			tag: eventWrapper.inner.tag,
-			val: eventWrapper.inner.val,
+			event: stringifyEvent(eventWrapper.inner),
+			index: eventWrapper.index.toString(),
 		});
 
 		this.__sendToServer({
diff --git a/engine/sdks/typescript/runner/src/stringify.ts b/engine/sdks/typescript/runner/src/stringify.ts
new file mode 100644
index 0000000000..699b2745c1
--- /dev/null
+++ b/engine/sdks/typescript/runner/src/stringify.ts
@@ -0,0 +1,184 @@
+import type * as protocol from "@rivetkit/engine-runner-protocol";
+
+/**
+ * Helper function to stringify ArrayBuffer for logging
+ */
+function stringifyArrayBuffer(buffer: ArrayBuffer): string {
+	return `ArrayBuffer(${buffer.byteLength})`;
+}
+
+/**
+ * Helper function to stringify bigint for logging
+ */
+function stringifyBigInt(value: bigint): string {
+	return `${value}n`;
+}
+
+/**
+ * Helper function to stringify Map for logging
+ */
+function stringifyMap(map: ReadonlyMap<string, string>): string {
+	const entries = Array.from(map.entries())
+		.map(([k, v]) => `"${k}": "${v}"`)
+		.join(", ");
+	return `Map(${map.size}){${entries}}`;
+}
+
+/**
+ * Stringify ToServerTunnelMessageKind for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyToServerTunnelMessageKind(
+	kind: protocol.ToServerTunnelMessageKind,
+): string {
+	switch (kind.tag) {
+		case "TunnelAck":
+			return "TunnelAck";
+		case "ToServerResponseStart": {
+			const { status, headers, body, stream } = kind.val;
+			const bodyStr = body === null ? "null" : stringifyArrayBuffer(body);
+			return `ToServerResponseStart{status: ${status}, headers: ${stringifyMap(headers)}, body: ${bodyStr}, stream: ${stream}}`;
+		}
+		case "ToServerResponseChunk": {
+			const { body, finish } = kind.val;
+			return `ToServerResponseChunk{body: ${stringifyArrayBuffer(body)}, finish: ${finish}}`;
+		}
+		case "ToServerResponseAbort":
+			return "ToServerResponseAbort";
+		case "ToServerWebSocketOpen": {
+			const { canHibernate, lastMsgIndex } = kind.val;
+			return `ToServerWebSocketOpen{canHibernate: ${canHibernate}, lastMsgIndex: ${stringifyBigInt(lastMsgIndex)}}`;
+		}
+		case "ToServerWebSocketMessage": {
+			const { data, binary } = kind.val;
+			return `ToServerWebSocketMessage{data: ${stringifyArrayBuffer(data)}, binary: ${binary}}`;
+		}
+		case "ToServerWebSocketMessageAck": {
+			const { index } = kind.val;
+			return `ToServerWebSocketMessageAck{index: ${index}}`;
+		}
+		case "ToServerWebSocketClose": {
+			const { code, reason, retry } = kind.val;
+			const codeStr = code === null ? "null" : code.toString();
+			const reasonStr = reason === null ? "null" : `"${reason}"`;
+			return `ToServerWebSocketClose{code: ${codeStr}, reason: ${reasonStr}, retry: ${retry}}`;
+		}
+	}
+}
+
+/**
+ * Stringify ToClientTunnelMessageKind for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyToClientTunnelMessageKind(
+	kind: protocol.ToClientTunnelMessageKind,
+): string {
+	switch (kind.tag) {
+		case "TunnelAck":
+			return "TunnelAck";
+		case "ToClientRequestStart": {
+			const { actorId, method, path, headers, body, stream } = kind.val;
+			const bodyStr = body === null ? "null" : stringifyArrayBuffer(body);
+			return `ToClientRequestStart{actorId: "${actorId}", method: "${method}", path: "${path}", headers: ${stringifyMap(headers)}, body: ${bodyStr}, stream: ${stream}}`;
+		}
+		case "ToClientRequestChunk": {
+			const { body, finish } = kind.val;
+			return `ToClientRequestChunk{body: ${stringifyArrayBuffer(body)}, finish: ${finish}}`;
+		}
+		case "ToClientRequestAbort":
+			return "ToClientRequestAbort";
+		case "ToClientWebSocketOpen": {
+			const { actorId, path, headers } = kind.val;
+			return `ToClientWebSocketOpen{actorId: "${actorId}", path: "${path}", headers: ${stringifyMap(headers)}}`;
+		}
+		case "ToClientWebSocketMessage": {
+			const { index, data, binary } = kind.val;
+			return `ToClientWebSocketMessage{index: ${index}, data: ${stringifyArrayBuffer(data)}, binary: ${binary}}`;
+		}
+		case "ToClientWebSocketClose": {
+			const { code, reason } = kind.val;
+			const codeStr = code === null ? "null" : code.toString();
+			const reasonStr = reason === null ? "null" : `"${reason}"`;
+			return `ToClientWebSocketClose{code: ${codeStr}, reason: ${reasonStr}}`;
+		}
+	}
+}
+
+/**
+ * Stringify Command for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyCommand(command: protocol.Command): string {
+	switch (command.tag) {
+		case "CommandStartActor": {
+			const { actorId, generation, config } = command.val;
+			const keyStr = config.key === null ? "null" : `"${config.key}"`;
+			const inputStr =
+				config.input === null
+					? "null"
+					: stringifyArrayBuffer(config.input);
+			return `CommandStartActor{actorId: "${actorId}", generation: ${generation}, config: {name: "${config.name}", key: ${keyStr}, createTs: ${stringifyBigInt(config.createTs)}, input: ${inputStr}}}`;
+		}
+		case "CommandStopActor": {
+			const { actorId, generation } = command.val;
+			return `CommandStopActor{actorId: "${actorId}", generation: ${generation}}`;
+		}
+	}
+}
+
+/**
+ * Stringify CommandWrapper for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyCommandWrapper(
+	wrapper: protocol.CommandWrapper,
+): string {
+	return `CommandWrapper{index: ${stringifyBigInt(wrapper.index)}, inner: ${stringifyCommand(wrapper.inner)}}`;
+}
+
+/**
+ * Stringify Event for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyEvent(event: protocol.Event): string {
+	switch (event.tag) {
+		case "EventActorIntent": {
+			const { actorId, generation, intent } = event.val;
+			const intentStr =
+				intent.tag === "ActorIntentSleep"
+					? "Sleep"
+					: intent.tag === "ActorIntentStop"
+						? "Stop"
+						: "Unknown";
+			return `EventActorIntent{actorId: "${actorId}", generation: ${generation}, intent: ${intentStr}}`;
+		}
+		case "EventActorStateUpdate": {
+			const { actorId, generation, state } = event.val;
+			let stateStr: string;
+			if (state.tag === "ActorStateRunning") {
+				stateStr = "Running";
+			} else if (state.tag === "ActorStateStopped") {
+				const { code, message } = state.val;
+				const messageStr = message === null ? "null" : `"${message}"`;
+				stateStr = `Stopped{code: ${code}, message: ${messageStr}}`;
+			} else {
+				stateStr = "Unknown";
+			}
+			return `EventActorStateUpdate{actorId: "${actorId}", generation: ${generation}, state: ${stateStr}}`;
+		}
+		case "EventActorSetAlarm": {
+			const { actorId, generation, alarmTs } = event.val;
+			const alarmTsStr =
+				alarmTs === null ? "null" : stringifyBigInt(alarmTs);
+			return `EventActorSetAlarm{actorId: "${actorId}", generation: ${generation}, alarmTs: ${alarmTsStr}}`;
+		}
+	}
+}
+
+/**
+ * Stringify EventWrapper for logging
+ * Handles ArrayBuffers, BigInts, and Maps that can't be JSON.stringified
+ */
+export function stringifyEventWrapper(wrapper: protocol.EventWrapper): string {
+	return `EventWrapper{index: ${stringifyBigInt(wrapper.index)}, inner: ${stringifyEvent(wrapper.inner)}}`;
+}
diff --git a/engine/sdks/typescript/runner/src/tunnel.ts b/engine/sdks/typescript/runner/src/tunnel.ts
index 5c62b6b5dd..5ca1326f57 100644
--- a/engine/sdks/typescript/runner/src/tunnel.ts
+++ b/engine/sdks/typescript/runner/src/tunnel.ts
@@ -4,6 +4,10 @@ import type { Logger } from "pino";
 import { stringify as uuidstringify, v4 as uuidv4 } from "uuid";
 import { logger } from "./log";
 import type { ActorInstance, Runner } from "./mod";
+import {
+	stringifyToClientTunnelMessageKind,
+	stringifyToServerTunnelMessageKind,
+} from "./stringify";
 import { unreachable } from "./utils";
 import { WebSocketTunnelAdapter } from "./websocket-tunnel-adapter";
 
@@ -90,9 +94,11 @@ export class Tunnel {
 	) {
 		// TODO: Switch this with runner WS
 		if (!this.#runner.__webSocketReady()) {
-			this.log?.warn(
-				"cannot send tunnel message, socket not connected to engine",
-			);
+			this.log?.warn({
+				msg: "cannot send tunnel message, socket not connected to engine",
+				requestId: idToStr(requestId),
+				message: stringifyToServerTunnelMessageKind(messageKind),
+			});
 			return;
 		}
 
@@ -110,7 +116,7 @@ export class Tunnel {
 			msg: "send tunnel msg",
 			requestId: requestIdStr,
 			messageId: messageIdStr,
-			message: messageKind,
+			message: stringifyToServerTunnelMessageKind(messageKind),
 		});
 
 		// Send message
@@ -283,7 +289,7 @@ export class Tunnel {
 			msg: "receive tunnel msg",
 			requestId: requestIdStr,
 			messageId: messageIdStr,
-			message: message.messageKind,
+			message: stringifyToClientTunnelMessageKind(message.messageKind),
 		});
 
 		if (message.messageKind.tag === "TunnelAck") {