diff --git a/apps/desktop/src/main/lib/todo-daemon/client.ts b/apps/desktop/src/main/lib/todo-daemon/client.ts
index 02921275bae..756eecfc62e 100644
--- a/apps/desktop/src/main/lib/todo-daemon/client.ts
+++ b/apps/desktop/src/main/lib/todo-daemon/client.ts
@@ -27,6 +27,7 @@ import { connect, type Socket } from "node:net";
 import { homedir } from "node:os";
 import { join } from "node:path";
 import { app } from "electron";
+import { todoAgentMainDebug } from "main/todo-agent/debug";
 import { SUPERSET_DIR_NAME } from "shared/constants";
 import {
 	type AbortRequest,
@@ -221,6 +222,17 @@ export class TodoDaemonClient extends EventEmitter {
 				this.activeSessionIds = Array.isArray(response.activeSessionIds)
 					? response.activeSessionIds.slice()
 					: [];
+				todoAgentMainDebug.info(
+					"todo-daemon-client-authenticated",
+					{
+						protocolVersion: response.protocolVersion,
+						activeSessionCount: this.activeSessionIds.length,
+					},
+					{
+						captureMessage: true,
+						fingerprint: ["todo.agent.main", "todo-daemon-client-authenticated"],
+					},
+				);
 				return;
 			} catch (error) {
 				if (attempt === 0) {
@@ -640,8 +652,52 @@ export class TodoDaemonClient extends EventEmitter {
 	// =========================================================================
 
 	async start(request: StartRequest): Promise<EmptyResponse> {
-		await this.ensureConnected();
-		return this.sendRequest<EmptyResponse>("start", request);
+		todoAgentMainDebug.info(
+			"todo-daemon-client-start-request",
+			{
+				sessionId: request.sessionId,
+				fromScheduledWakeup: request.fromScheduledWakeup ?? false,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-daemon-client-start-request"],
+			},
+		);
+		try {
+			await this.ensureConnected();
+			const response = await this.sendRequest<EmptyResponse>("start", request);
+			todoAgentMainDebug.info(
+				"todo-daemon-client-start-request-success",
+				{
+					sessionId: request.sessionId,
+					fromScheduledWakeup: request.fromScheduledWakeup ?? false,
+				},
+				{
+					captureMessage: true,
+					fingerprint: [
+						"todo.agent.main",
+						"todo-daemon-client-start-request-success",
+					],
+				},
+			);
+			return response;
+		} catch (error) {
+			todoAgentMainDebug.captureException(
+				error,
+				"todo-daemon-client-start-request-failed",
+				{
+					sessionId: request.sessionId,
+					fromScheduledWakeup: request.fromScheduledWakeup ?? false,
+				},
+				{
+					fingerprint: [
+						"todo.agent.main",
+						"todo-daemon-client-start-request-failed",
+					],
+				},
+			);
+			throw error;
+		}
 	}
 
 	async abort(request: AbortRequest): Promise<EmptyResponse> {
@@ -667,8 +723,31 @@ export class TodoDaemonClient extends EventEmitter {
 	}
 
 	async rehydrate(): Promise<EmptyResponse> {
-		await this.ensureConnected();
-		return this.sendRequest<EmptyResponse>("rehydrate", {});
+		try {
+			await this.ensureConnected();
+			const response = await this.sendRequest<EmptyResponse>("rehydrate", {});
+			todoAgentMainDebug.info(
+				"todo-daemon-client-rehydrate-success",
+				{
+					activeSessionCount: this.activeSessionIds.length,
+				},
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-daemon-client-rehydrate-success"],
+				},
+			);
+			return response;
+		} catch (error) {
+			todoAgentMainDebug.captureException(
+				error,
+				"todo-daemon-client-rehydrate-failed",
+				undefined,
+				{
+					fingerprint: ["todo.agent.main", "todo-daemon-client-rehydrate-failed"],
+				},
+			);
+			throw error;
+		}
 	}
 
 	async listActive(): Promise<ListActiveResponse> {
diff --git a/apps/desktop/src/main/todo-agent/daemon-bridge.ts b/apps/desktop/src/main/todo-agent/daemon-bridge.ts
index 413631f600f..c4b976e6b86 100644
--- a/apps/desktop/src/main/todo-agent/daemon-bridge.ts
+++ b/apps/desktop/src/main/todo-agent/daemon-bridge.ts
@@ -2,6 +2,12 @@ import {
 	disposeTodoDaemonClient,
 	getTodoDaemonClient,
 } from "main/lib/todo-daemon/client";
+import {
+	getTodoSessionDebugData,
+	getTodoStreamBatchDebugData,
+	getTodoStreamEventDebugData,
+	todoAgentMainDebug,
+} from "./debug";
 import { getTodoSessionStore } from "./session-store";
 
 /**
@@ -21,9 +27,46 @@ export function startTodoAgentDaemonBridge(): Promise<void> {
 	if (!wired) {
 		wired = true;
 		client.on("sessionState", (payload) => {
+			todoAgentMainDebug.info(
+				"todo-daemon-bridge-session-state",
+				getTodoSessionDebugData(payload.session),
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-daemon-bridge-session-state"],
+				},
+			);
 			getTodoSessionStore().externalEmit(payload.session);
 		});
 		client.on("streamEvents", (payload) => {
+			todoAgentMainDebug.info(
+				"todo-daemon-bridge-stream-batch",
+				getTodoStreamBatchDebugData(payload.sessionId, payload.events),
+			);
+			for (const event of payload.events) {
+				if (
+					event.kind !== "system_init" &&
+					event.kind !== "error" &&
+					event.kind !== "remote_control" &&
+					event.kind !== "remote_control_error"
+				) {
+					continue;
+				}
+				todoAgentMainDebug.info(
+					"todo-daemon-bridge-stream-event",
+					{
+						sessionId: payload.sessionId,
+						...getTodoStreamEventDebugData(event),
+					},
+					{
+						captureMessage: true,
+						fingerprint: [
+							"todo.agent.main",
+							"todo-daemon-bridge-stream-event",
+							event.kind,
+						],
+					},
+				);
+			}
 			getTodoSessionStore().externalEmitStream(
 				payload.sessionId,
 				payload.events,
@@ -33,17 +76,57 @@ export function startTodoAgentDaemonBridge(): Promise<void> {
 			console.warn(
 				"[todo-agent] daemon disconnected — will reconnect on next RPC",
 			);
+			todoAgentMainDebug.warn(
+				"todo-daemon-bridge-disconnected",
+				undefined,
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-daemon-bridge-disconnected"],
+				},
+			);
 		});
 		client.on("error", (error) => {
 			console.warn("[todo-agent] daemon client error", error);
+			todoAgentMainDebug.captureException(
+				error,
+				"todo-daemon-bridge-error",
+				undefined,
+				{
+					fingerprint: ["todo.agent.main", "todo-daemon-bridge-error"],
+				},
+			);
 		});
 	}
 	connectPromise = (async () => {
+		todoAgentMainDebug.info(
+			"todo-daemon-bridge-init",
+			undefined,
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-daemon-bridge-init"],
+			},
+		);
 		try {
 			await client.ensureConnected();
 			await client.rehydrate();
+			todoAgentMainDebug.info(
+				"todo-daemon-bridge-init-success",
+				undefined,
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-daemon-bridge-init-success"],
+				},
+			);
 		} catch (error) {
 			console.warn("[todo-agent] daemon bridge failed to initialize", error);
+			todoAgentMainDebug.captureException(
+				error,
+				"todo-daemon-bridge-init-failed",
+				undefined,
+				{
+					fingerprint: ["todo.agent.main", "todo-daemon-bridge-init-failed"],
+				},
+			);
 			// Drop the cached promise so a later retry can try again.
 			connectPromise = null;
 			throw error;
diff --git a/apps/desktop/src/main/todo-agent/debug.ts b/apps/desktop/src/main/todo-agent/debug.ts
new file mode 100644
index 00000000000..51e2f3f7e9b
--- /dev/null
+++ b/apps/desktop/src/main/todo-agent/debug.ts
@@ -0,0 +1,77 @@
+import type { SelectTodoSession } from "@superset/local-db";
+import type { TodoStreamEvent } from "./types";
+import { createMainDebugChannel } from "../lib/debug-channel";
+
+const DEBUG_TODO_AGENT = process.env.SUPERSET_TODO_DEBUG === "1";
+
+// TODO Agent の作成から daemon 実行、PTY / Remote Control 分岐までを
+// 一回の Sentry ログで追えるようにするための main/daemon 共通 logger。
+// 主に見たいのは:
+// - renderer から送った PTY / Remote の意図が main で落ちていないか
+// - runtime-config.json に正しく保存 / 読み出しできたか
+// - daemon が headless / PTY / Remote Control をどう最終判定したか
+// - PTY 起動後に Remote Control URL 発行まで進んだか
+// Sentry には常時送り、console ミラーだけ env フラグで制御する。
+export const todoAgentMainDebug = createMainDebugChannel({
+	namespace: "todo.agent.main",
+	enabled: true,
+	mirrorToConsole: DEBUG_TODO_AGENT,
+});
+
+export function getTodoSessionDebugData(
+	session: Pick<
+		SelectTodoSession,
+		| "id"
+		| "workspaceId"
+		| "projectId"
+		| "status"
+		| "phase"
+		| "iteration"
+		| "artifactPath"
+		| "remoteControlEnabled"
+		| "claudeSessionId"
+		| "verdictReason"
+		| "waitingReason"
+	>
+) {
+	return {
+		sessionId: session.id,
+		workspaceId: session.workspaceId,
+		projectId: session.projectId ?? null,
+		status: session.status,
+		phase: session.phase,
+		iteration: session.iteration,
+		artifactPath: session.artifactPath,
+		remoteControlEnabled: session.remoteControlEnabled ?? false,
+		hasClaudeSessionId: Boolean(session.claudeSessionId),
+		verdictReason: session.verdictReason ?? null,
+		waitingReason: session.waitingReason ?? null,
+	};
+}
+
+export function getTodoStreamEventDebugData(
+	event: Pick<TodoStreamEvent, "id" | "iteration" | "kind" | "label" | "text">,
+) {
+	return {
+		eventId: event.id,
+		iteration: event.iteration,
+		kind: event.kind,
+		label: event.label,
+		textPreview: event.text,
+	};
+}
+
+export function getTodoStreamBatchDebugData(
+	sessionId: string,
+	events: readonly Pick<TodoStreamEvent, "kind">[],
+) {
+	const kinds = Array.from(new Set(events.map((event) => event.kind)));
+	const lastEvent = events.length > 0 ? events[events.length - 1] : null;
+	return {
+		sessionId,
+		eventCount: events.length,
+		eventKinds: kinds.join(","),
+		firstKind: events[0]?.kind ?? null,
+		lastKind: lastEvent?.kind ?? null,
+	};
+}
diff --git a/apps/desktop/src/main/todo-agent/runtime-config.ts b/apps/desktop/src/main/todo-agent/runtime-config.ts
index f2052c29818..31033494a1a 100644
--- a/apps/desktop/src/main/todo-agent/runtime-config.ts
+++ b/apps/desktop/src/main/todo-agent/runtime-config.ts
@@ -1,5 +1,6 @@
 import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
 import path from "node:path";
+import { todoAgentMainDebug } from "./debug";
 
 const TODO_RUNTIME_CONFIG_FILE = "runtime-config.json";
 
@@ -33,11 +34,38 @@ export function readTodoSessionRuntimeConfig(params: {
 		remoteControlEnabled: legacyRemoteControlEnabled,
 	};
 	if (!path.isAbsolute(params.artifactPath)) {
+		todoAgentMainDebug.warn(
+			"todo-runtime-config-read-fallback",
+			{
+				artifactPath: params.artifactPath,
+				reason: "artifact-path-not-absolute",
+				fallbackPtyEnabled: legacyFallback.ptyEnabled,
+				fallbackRemoteControlEnabled: legacyFallback.remoteControlEnabled,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-runtime-config-read-fallback"],
+			},
+		);
 		return legacyFallback;
 	}
 
 	const filePath = getRuntimeConfigPath(params.artifactPath);
 	if (!existsSync(filePath)) {
+		todoAgentMainDebug.warn(
+			"todo-runtime-config-read-fallback",
+			{
+				artifactPath: params.artifactPath,
+				filePath,
+				reason: "runtime-config-missing",
+				fallbackPtyEnabled: legacyFallback.ptyEnabled,
+				fallbackRemoteControlEnabled: legacyFallback.remoteControlEnabled,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-runtime-config-read-fallback"],
+			},
+		);
 		return legacyFallback;
 	}
 
@@ -46,14 +74,56 @@ export function readTodoSessionRuntimeConfig(params: {
 			readFileSync(filePath, "utf8"),
 		) as Partial<TodoSessionRuntimeConfig> | null;
 		if (!parsed || typeof parsed !== "object") {
+			todoAgentMainDebug.warn(
+				"todo-runtime-config-read-fallback",
+				{
+					artifactPath: params.artifactPath,
+					filePath,
+					reason: "runtime-config-invalid-json-shape",
+					fallbackPtyEnabled: legacyFallback.ptyEnabled,
+					fallbackRemoteControlEnabled: legacyFallback.remoteControlEnabled,
+				},
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-runtime-config-read-fallback"],
+				},
+			);
 			return legacyFallback;
 		}
-		return normalizeConfig({
+		const normalized = normalizeConfig({
 			ptyEnabled: parsed.ptyEnabled === true,
 			remoteControlEnabled: parsed.remoteControlEnabled === true,
 		});
+		todoAgentMainDebug.info(
+			"todo-runtime-config-read",
+			{
+				artifactPath: params.artifactPath,
+				filePath,
+				ptyEnabled: normalized.ptyEnabled,
+				remoteControlEnabled: normalized.remoteControlEnabled,
+				usedFallback: false,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-runtime-config-read"],
+			},
+		);
+		return normalized;
 	} catch (error) {
 		console.warn("[todo-agent] failed to read runtime config", error);
+		todoAgentMainDebug.captureException(
+			error,
+			"todo-runtime-config-read-failed",
+			{
+				artifactPath: params.artifactPath,
+				filePath,
+				fallbackPtyEnabled: legacyFallback.ptyEnabled,
+				fallbackRemoteControlEnabled: legacyFallback.remoteControlEnabled,
+			},
+			{
+				fingerprint: ["todo.agent.main", "todo-runtime-config-read-failed"],
+			},
+		);
 		return legacyFallback;
 	}
 }
@@ -62,15 +132,57 @@ export function writeTodoSessionRuntimeConfig(
 	artifactPath: string,
 	config: TodoSessionRuntimeConfig,
 ): void {
-	if (!path.isAbsolute(artifactPath)) return;
+	if (!path.isAbsolute(artifactPath)) {
+		todoAgentMainDebug.warn(
+			"todo-runtime-config-write-skipped",
+			{
+				artifactPath,
+				reason: "artifact-path-not-absolute",
+				ptyEnabled: config.ptyEnabled,
+				remoteControlEnabled: config.remoteControlEnabled,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-runtime-config-write-skipped"],
+			},
+		);
+		return;
+	}
 	try {
+		const normalized = normalizeConfig(config);
+		const filePath = getRuntimeConfigPath(artifactPath);
 		mkdirSync(artifactPath, { recursive: true });
 		writeFileSync(
-			getRuntimeConfigPath(artifactPath),
-			`${JSON.stringify(normalizeConfig(config), null, 2)}\n`,
+			filePath,
+			`${JSON.stringify(normalized, null, 2)}\n`,
 			"utf8",
 		);
+		todoAgentMainDebug.info(
+			"todo-runtime-config-write",
+			{
+				artifactPath,
+				filePath,
+				ptyEnabled: normalized.ptyEnabled,
+				remoteControlEnabled: normalized.remoteControlEnabled,
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-runtime-config-write"],
+			},
+		);
 	} catch (error) {
 		console.warn("[todo-agent] failed to write runtime config", error);
+		todoAgentMainDebug.captureException(
+			error,
+			"todo-runtime-config-write-failed",
+			{
+				artifactPath,
+				ptyEnabled: config.ptyEnabled,
+				remoteControlEnabled: config.remoteControlEnabled,
+			},
+			{
+				fingerprint: ["todo.agent.main", "todo-runtime-config-write-failed"],
+			},
+		);
 	}
 }
diff --git a/apps/desktop/src/main/todo-agent/supervisor.ts b/apps/desktop/src/main/todo-agent/supervisor.ts
index f0b36559e2d..5ea996798c3 100644
--- a/apps/desktop/src/main/todo-agent/supervisor.ts
+++ b/apps/desktop/src/main/todo-agent/supervisor.ts
@@ -2,6 +2,7 @@ import { mkdirSync, writeFileSync } from "node:fs";
 import path from "node:path";
 import type { SelectTodoSession } from "@superset/local-db";
 import { getTodoDaemonClient } from "main/lib/todo-daemon/client";
+import { getTodoSessionDebugData, todoAgentMainDebug } from "./debug";
 import { getTodoSessionStore, resolveWorktreePath } from "./session-store";
 import { TODO_ARTIFACT_SUBDIR } from "./types";
 
@@ -41,11 +42,35 @@ class TodoSupervisor {
 		sessionId: string,
 		options?: { fromScheduledWakeup?: boolean },
 	): Promise<void> {
+		const current = getTodoSessionStore().get(sessionId);
+		todoAgentMainDebug.info(
+			"todo-supervisor-start",
+			{
+				sessionId,
+				fromScheduledWakeup: options?.fromScheduledWakeup ?? false,
+				...(current ? getTodoSessionDebugData(current) : {}),
+			},
+			{
+				captureMessage: true,
+				fingerprint: ["todo.agent.main", "todo-supervisor-start"],
+			},
+		);
 		try {
 			await getTodoDaemonClient().start({
 				sessionId,
 				fromScheduledWakeup: options?.fromScheduledWakeup,
 			});
+			todoAgentMainDebug.info(
+				"todo-supervisor-start-success",
+				{
+					sessionId,
+					fromScheduledWakeup: options?.fromScheduledWakeup ?? false,
+				},
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.main", "todo-supervisor-start-success"],
+				},
+			);
 		} catch (error) {
 			// The tRPC router flips the session to `preparing` before
 			// fire-and-forgetting us, so a daemon spawn/connect/auth
@@ -55,6 +80,18 @@ class TodoSupervisor {
 			// can retry or delete the session.
 			const reason = error instanceof Error ? error.message : String(error);
 			console.warn("[todo-supervisor] daemon start failed", error);
+			todoAgentMainDebug.captureException(
+				error,
+				"todo-supervisor-start-failed",
+				{
+					sessionId,
+					fromScheduledWakeup: options?.fromScheduledWakeup ?? false,
+					errorMessage: reason,
+				},
+				{
+					fingerprint: ["todo.agent.main", "todo-supervisor-start-failed"],
+				},
+			);
 			try {
 				const store = getTodoSessionStore();
 				const current = store.get(sessionId);
diff --git a/apps/desktop/src/main/todo-agent/trpc-router.ts b/apps/desktop/src/main/todo-agent/trpc-router.ts
index 5d3a2f439df..7d47d78ff2f 100644
--- a/apps/desktop/src/main/todo-agent/trpc-router.ts
+++ b/apps/desktop/src/main/todo-agent/trpc-router.ts
@@ -25,6 +25,7 @@ import { computeNextRunAt, getTodoScheduler } from "./scheduler";
 import { getTodoSessionStore, resolveWorktreePath } from "./session-store";
 import { getTodoSettings, updateTodoSettings } from "./settings";
 import { getTodoSupervisor } from "./supervisor";
+import { getTodoSessionDebugData, todoAgentMainDebug } from "./debug";
 import {
 	TODO_ARTIFACT_SUBDIR,
 	type TodoScheduleFireEvent,
@@ -52,104 +53,153 @@ export const createTodoAgentRouter = () => {
 		create: publicProcedure
 			.input(todoCreateInputSchema)
 			.mutation(async ({ input }) => {
-				// When the UI creates a fresh workspace+worktree immediately
-				// before creating the TODO (the "新しい worktree を作成して実行"
-				// checkbox), `workspaces.create` returns while `git worktree
-				// add` is still running in the background. Materializing the
-				// artifact directory now would mkdir inside the future
-				// worktree path, leaving it non-empty and causing the
-				// subsequent `git worktree add` to fail — the symptom users
-				// see as the sidebar error + "ブランチ取得中…" that never
-				// resolves. Block until init is done (or already no-op) so
-				// prepareArtifacts runs against a real worktree.
-				//
-				// `waitForInit` has a 30s internal timeout that resolves
-				// silently even if init is still running, so a slow
-				// fetch/clone path could still slip through. Loop on the
-				// `isInitializing` flag so we really block until the job
-				// reaches a terminal state, up to a generous ceiling.
-				const INIT_WAIT_STEP_MS = 30_000;
-				const INIT_WAIT_CEILING_MS = 10 * 60_000;
-				const waitStartedAt = Date.now();
-				while (workspaceInitManager.isInitializing(input.workspaceId)) {
-					if (Date.now() - waitStartedAt > INIT_WAIT_CEILING_MS) {
+				todoAgentMainDebug.info(
+					"todo-create-request",
+					{
+						workspaceId: input.workspaceId,
+						projectId: input.projectId ?? null,
+						ptyEnabled: input.ptyEnabled,
+						remoteControlEnabled: input.remoteControlEnabled,
+						maxIterations: input.maxIterations,
+						maxWallClockSec: input.maxWallClockSec,
+						hasVerify: (input.verifyCommand?.trim().length ?? 0) > 0,
+						hasCustomSystemPrompt:
+							(input.customSystemPrompt?.trim().length ?? 0) > 0,
+					},
+					{
+						captureMessage: true,
+						fingerprint: ["todo.agent.main", "todo-create-request"],
+					},
+				);
+				try {
+					// When the UI creates a fresh workspace+worktree immediately
+					// before creating the TODO (the "新しい worktree を作成して実行"
+					// checkbox), `workspaces.create` returns while `git worktree
+					// add` is still running in the background. Materializing the
+					// artifact directory now would mkdir inside the future
+					// worktree path, leaving it non-empty and causing the
+					// subsequent `git worktree add` to fail — the symptom users
+					// see as the sidebar error + "ブランチ取得中…" that never
+					// resolves. Block until init is done (or already no-op) so
+					// prepareArtifacts runs against a real worktree.
+					//
+					// `waitForInit` has a 30s internal timeout that resolves
+					// silently even if init is still running, so a slow
+					// fetch/clone path could still slip through. Loop on the
+					// `isInitializing` flag so we really block until the job
+					// reaches a terminal state, up to a generous ceiling.
+					const INIT_WAIT_STEP_MS = 30_000;
+					const INIT_WAIT_CEILING_MS = 10 * 60_000;
+					const waitStartedAt = Date.now();
+					while (workspaceInitManager.isInitializing(input.workspaceId)) {
+						if (Date.now() - waitStartedAt > INIT_WAIT_CEILING_MS) {
+							throw new TRPCError({
+								code: "TIMEOUT",
+								message: `todo-agent: workspace ${input.workspaceId} の初期化が時間内に終わりませんでした`,
+							});
+						}
+						await workspaceInitManager.waitForInit(
+							input.workspaceId,
+							INIT_WAIT_STEP_MS,
+						);
+					}
+					if (workspaceInitManager.hasFailed(input.workspaceId)) {
 						throw new TRPCError({
-							code: "TIMEOUT",
-							message: `todo-agent: workspace ${input.workspaceId} の初期化が時間内に終わりませんでした`,
+							code: "PRECONDITION_FAILED",
+							message: `todo-agent: workspace ${input.workspaceId} の初期化に失敗しました`,
 						});
 					}
-					await workspaceInitManager.waitForInit(
-						input.workspaceId,
-						INIT_WAIT_STEP_MS,
-					);
-				}
-				if (workspaceInitManager.hasFailed(input.workspaceId)) {
-					throw new TRPCError({
-						code: "PRECONDITION_FAILED",
-						message: `todo-agent: workspace ${input.workspaceId} の初期化に失敗しました`,
-					});
-				}
 
-				const store = getTodoSessionStore();
-				const worktreePath = resolveWorktreePath(input.workspaceId);
-				if (!worktreePath) {
-					throw new Error(
-						`todo-agent: workspace ${input.workspaceId} のパスを解決できませんでした`,
-					);
-				}
+					const store = getTodoSessionStore();
+					const worktreePath = resolveWorktreePath(input.workspaceId);
+					if (!worktreePath) {
+						throw new Error(
+							`todo-agent: workspace ${input.workspaceId} のパスを解決できませんでした`,
+						);
+					}
 
-				// Compute the final artifact path up-front so the row is
-				// inserted with its permanent path in one shot. No more
-				// half-written PENDING rows left behind if the process
-				// crashes between insert and update.
-				const sessionId = randomUUID();
-				const supervisor = getTodoSupervisor();
-				const artifactPath = supervisor.computeArtifactPath({
-					sessionId,
-					workspaceId: input.workspaceId,
-				});
+					// Compute the final artifact path up-front so the row is
+					// inserted with its permanent path in one shot. No more
+					// half-written PENDING rows left behind if the process
+					// crashes between insert and update.
+					const sessionId = randomUUID();
+					const supervisor = getTodoSupervisor();
+					const artifactPath = supervisor.computeArtifactPath({
+						sessionId,
+						workspaceId: input.workspaceId,
+					});
 
-				// Fall through to the user's configured defaults when the
-				// composer did not pick an explicit model / effort. Null
-				// at both levels means "use Claude Code's own default"
-				// (we simply omit the CLI flag at spawn time).
-				const settings = getTodoSettings();
-				const resolvedModel =
-					input.claudeModel !== undefined
-						? input.claudeModel
-						: (settings.defaultClaudeModel ?? null);
-				const resolvedEffort =
-					input.claudeEffort !== undefined
-						? input.claudeEffort
-						: (settings.defaultClaudeEffort ?? null);
-
-				const session = store.insertQueuedFromTemplate({
-					id: sessionId,
-					projectId: input.projectId ?? null,
-					workspaceId: input.workspaceId,
-					title: input.title ?? "",
-					description: input.description,
-					goal: input.goal,
-					verifyCommand: input.verifyCommand,
-					maxIterations: input.maxIterations,
-					maxWallClockSec: input.maxWallClockSec,
-					customSystemPrompt: input.customSystemPrompt,
-					claudeModel: resolvedModel,
-					claudeEffort: resolvedEffort,
-					remoteControlEnabled: input.remoteControlEnabled,
-					artifactPath,
-				});
+					// Fall through to the user's configured defaults when the
+					// composer did not pick an explicit model / effort. Null
+					// at both levels means "use Claude Code's own default"
+					// (we simply omit the CLI flag at spawn time).
+					const settings = getTodoSettings();
+					const resolvedModel =
+						input.claudeModel !== undefined
+							? input.claudeModel
+							: (settings.defaultClaudeModel ?? null);
+					const resolvedEffort =
+						input.claudeEffort !== undefined
+							? input.claudeEffort
+							: (settings.defaultClaudeEffort ?? null);
+
+					const session = store.insertQueuedFromTemplate({
+						id: sessionId,
+						projectId: input.projectId ?? null,
+						workspaceId: input.workspaceId,
+						title: input.title ?? "",
+						description: input.description,
+						goal: input.goal,
+						verifyCommand: input.verifyCommand,
+						maxIterations: input.maxIterations,
+						maxWallClockSec: input.maxWallClockSec,
+						customSystemPrompt: input.customSystemPrompt,
+						claudeModel: resolvedModel,
+						claudeEffort: resolvedEffort,
+						remoteControlEnabled: input.remoteControlEnabled,
+						artifactPath,
+					});
 
-				// Materialize the directory + goal.md. If this throws after
-				// the row exists the user can delete the broken session
-				// from the Manager — same as any other filesystem error.
-				supervisor.prepareArtifacts(session);
-				writeTodoSessionRuntimeConfig(session.artifactPath, {
-					ptyEnabled: input.ptyEnabled,
-					remoteControlEnabled: input.remoteControlEnabled,
-				});
+					// Materialize the directory + goal.md. If this throws after
+					// the row exists the user can delete the broken session
+					// from the Manager — same as any other filesystem error.
+					supervisor.prepareArtifacts(session);
+					writeTodoSessionRuntimeConfig(session.artifactPath, {
+						ptyEnabled: input.ptyEnabled,
+						remoteControlEnabled: input.remoteControlEnabled,
+					});
 
-				return { sessionId: session.id };
+					todoAgentMainDebug.info(
+						"todo-create-request-success",
+						{
+							...getTodoSessionDebugData(session),
+							ptyEnabled: input.ptyEnabled,
+							remoteControlEnabled: input.remoteControlEnabled,
+							claudeModel: resolvedModel,
+							claudeEffort: resolvedEffort,
+						},
+						{
+							captureMessage: true,
+							fingerprint: ["todo.agent.main", "todo-create-request-success"],
+						},
+					);
+					return { sessionId: session.id };
+				} catch (error) {
+					todoAgentMainDebug.captureException(
+						error,
+						"todo-create-request-failed",
+						{
+							workspaceId: input.workspaceId,
+							projectId: input.projectId ?? null,
+							ptyEnabled: input.ptyEnabled,
+							remoteControlEnabled: input.remoteControlEnabled,
+						},
+						{
+							fingerprint: ["todo.agent.main", "todo-create-request-failed"],
+						},
+					);
+					throw error;
+				}
 			}),
 
 		list: publicProcedure
@@ -226,6 +276,23 @@ export const createTodoAgentRouter = () => {
 					waitingUntil: null,
 					waitingReason: null,
 				});
+				const runtimeConfig = readTodoSessionRuntimeConfig({
+					artifactPath: session.artifactPath,
+					fallbackRemoteControlEnabled: session.remoteControlEnabled ?? false,
+				});
+				todoAgentMainDebug.info(
+					"todo-start-request",
+					{
+						...getTodoSessionDebugData(session),
+						runtimeConfigPtyEnabled: runtimeConfig.ptyEnabled,
+						runtimeConfigRemoteControlEnabled:
+							runtimeConfig.remoteControlEnabled,
+					},
+					{
+						captureMessage: true,
+						fingerprint: ["todo.agent.main", "todo-start-request"],
+					},
+				);
 				// Fire-and-forget: the supervisor drives the rest of the loop.
 				void getTodoSupervisor().start(input.sessionId);
 				return { ok: true };
@@ -412,6 +479,14 @@ export const createTodoAgentRouter = () => {
 						message: "元セッションが見つかりません",
 					});
 				}
+				todoAgentMainDebug.info(
+					"todo-rerun-request",
+					getTodoSessionDebugData(source),
+					{
+						captureMessage: true,
+						fingerprint: ["todo.agent.main", "todo-rerun-request"],
+					},
+				);
 
 				// Create a brand-new queued session that copies the user-
 				// authored fields from the source. Verdict / iteration /
@@ -465,6 +540,20 @@ export const createTodoAgentRouter = () => {
 					fallbackRemoteControlEnabled: source.remoteControlEnabled ?? false,
 				});
 				writeTodoSessionRuntimeConfig(next.artifactPath, runtimeConfig);
+				todoAgentMainDebug.info(
+					"todo-rerun-request-success",
+					{
+						sourceSessionId: source.id,
+						nextSessionId: next.id,
+						nextArtifactPath: next.artifactPath,
+						ptyEnabled: runtimeConfig.ptyEnabled,
+						remoteControlEnabled: runtimeConfig.remoteControlEnabled,
+					},
+					{
+						captureMessage: true,
+						fingerprint: ["todo.agent.main", "todo-rerun-request-success"],
+					},
+				);
 
 				return { sessionId: next.id };
 			}),
diff --git a/apps/desktop/src/renderer/features/todo-agent/TodoManager/TodoManager.tsx b/apps/desktop/src/renderer/features/todo-agent/TodoManager/TodoManager.tsx
index a840a7892f3..984ca5e2366 100644
--- a/apps/desktop/src/renderer/features/todo-agent/TodoManager/TodoManager.tsx
+++ b/apps/desktop/src/renderer/features/todo-agent/TodoManager/TodoManager.tsx
@@ -71,6 +71,7 @@ import {
 	LuPanelRightOpen,
 } from "react-icons/lu";
 import { MarkdownRenderer } from "renderer/components/MarkdownRenderer";
+import { todoAgentRendererDebug } from "renderer/features/todo-agent/debug";
 import { electronTrpc } from "renderer/lib/electron-trpc";
 import {
 	type ClaudeEffortPick,
@@ -2800,6 +2801,29 @@ function TodoComposer({
 				goal.trim(),
 				goalAttachments,
 			);
+			todoAgentRendererDebug.info(
+				"todo-create-submit",
+				{
+					source: "todo-manager-composer",
+					workspaceId: targetWorkspaceId,
+					projectId,
+					createWorktree,
+					ptyEnabled,
+					remoteControlEnabled,
+					titleLength: title.trim().length,
+					descriptionLength: resolvedDescription.length,
+					hasGoal: resolvedGoal.length > 0,
+					hasVerify: verifyCommand.trim().length > 0,
+				},
+				{
+					captureMessage: true,
+					fingerprint: [
+						"todo.agent.renderer",
+						"todo-create-submit",
+						"todo-manager-composer",
+					],
+				},
+			);
 			const res = await createMut.mutateAsync({
 				workspaceId: targetWorkspaceId,
 				projectId,
@@ -2815,6 +2839,24 @@ function TodoComposer({
 				ptyEnabled,
 				remoteControlEnabled,
 			});
+			todoAgentRendererDebug.info(
+				"todo-create-submit-success",
+				{
+					source: "todo-manager-composer",
+					sessionId: res.sessionId,
+					workspaceId: targetWorkspaceId,
+					ptyEnabled,
+					remoteControlEnabled,
+				},
+				{
+					captureMessage: true,
+					fingerprint: [
+						"todo.agent.renderer",
+						"todo-create-submit-success",
+						"todo-manager-composer",
+					],
+				},
+			);
 			await utils.todoAgent.listAll.invalidate();
 			toast.success(
 				createWorktree
@@ -2826,6 +2868,27 @@ function TodoComposer({
 			// to unmount via onCreated → re-enabling the button would
 			// flicker. The finally below only runs on error / throw.
 		} catch (error) {
+			todoAgentRendererDebug.captureException(
+				error,
+				"todo-create-submit-failed",
+				{
+					source: "todo-manager-composer",
+					projectId,
+					workspaceId,
+					createWorktree,
+					ptyEnabled,
+					remoteControlEnabled,
+					errorMessage:
+						error instanceof Error ? error.message : "作成に失敗しました",
+				},
+				{
+					fingerprint: [
+						"todo.agent.renderer",
+						"todo-create-submit-failed",
+						"todo-manager-composer",
+					],
+				},
+			);
 			toast.error(
 				error instanceof Error ? error.message : "作成に失敗しました",
 			);
diff --git a/apps/desktop/src/renderer/features/todo-agent/TodoModal/TodoModal.tsx b/apps/desktop/src/renderer/features/todo-agent/TodoModal/TodoModal.tsx
index d89cb0b9a26..587ad5e0049 100644
--- a/apps/desktop/src/renderer/features/todo-agent/TodoModal/TodoModal.tsx
+++ b/apps/desktop/src/renderer/features/todo-agent/TodoModal/TodoModal.tsx
@@ -33,6 +33,7 @@ import {
 	toPersistedEffort,
 	toPersistedModel,
 } from "../ClaudeRuntimePicker";
+import { todoAgentRendererDebug } from "../debug";
 import { EnhanceButton } from "./components/EnhanceButton";
 
 interface TodoModalProps {
@@ -199,6 +200,25 @@ export function TodoModal({
 				targetWorkspaceId = result.workspace.id;
 			}
 
+			todoAgentRendererDebug.info(
+				"todo-create-submit",
+				{
+					source: "todo-modal",
+					workspaceId: targetWorkspaceId,
+					projectId: projectId ?? null,
+					createWorktree,
+					ptyEnabled,
+					remoteControlEnabled,
+					titleLength: title.trim().length,
+					descriptionLength: description.trim().length,
+					hasGoal,
+					hasVerify,
+				},
+				{
+					captureMessage: true,
+					fingerprint: ["todo.agent.renderer", "todo-create-submit", "todo-modal"],
+				},
+			);
 			const created = await create.mutateAsync({
 				workspaceId: targetWorkspaceId,
 				projectId,
@@ -214,6 +234,24 @@ export function TodoModal({
 				ptyEnabled,
 				remoteControlEnabled,
 			});
+			todoAgentRendererDebug.info(
+				"todo-create-submit-success",
+				{
+					source: "todo-modal",
+					sessionId: created.sessionId,
+					workspaceId: targetWorkspaceId,
+					ptyEnabled,
+					remoteControlEnabled,
+				},
+				{
+					captureMessage: true,
+					fingerprint: [
+						"todo.agent.renderer",
+						"todo-create-submit-success",
+						"todo-modal",
+					],
+				},
+			);
 			if (createWorktree) {
 				toast.success(
 					"新しい worktree を作成して TODO セッションを紐付けました",
@@ -226,6 +264,22 @@ export function TodoModal({
 		} catch (error) {
 			const message =
 				error instanceof Error ? error.message : "作成に失敗しました";
+			todoAgentRendererDebug.captureException(
+				error,
+				"todo-create-submit-failed",
+				{
+					source: "todo-modal",
+					workspaceId,
+					projectId: projectId ?? null,
+					createWorktree,
+					ptyEnabled,
+					remoteControlEnabled,
+					errorMessage: message,
+				},
+				{
+					fingerprint: ["todo.agent.renderer", "todo-create-submit-failed", "todo-modal"],
+				},
+			);
 			toast.error(message);
 			setSubmitting(false);
 		}
diff --git a/apps/desktop/src/renderer/features/todo-agent/debug.ts b/apps/desktop/src/renderer/features/todo-agent/debug.ts
new file mode 100644
index 00000000000..80d2fc7e45b
--- /dev/null
+++ b/apps/desktop/src/renderer/features/todo-agent/debug.ts
@@ -0,0 +1,20 @@
+import { createRendererDebugChannel } from "renderer/lib/debug-channel";
+
+function isTodoAgentDebugEnabled(): boolean {
+	try {
+		return globalThis.localStorage?.getItem("SUPERSET_TODO_DEBUG") === "1";
+	} catch {
+		return false;
+	}
+}
+
+// TODO Agent の renderer 側 logger。
+// 作成 UI は TodoModal と AgentManager 内 composer の 2 系統あるため、
+// どちらから、どの PTY / Remote Control フラグで submit されたかを残す。
+// これにより main 側の runtime-config / daemon 判定ログと source を
+// sessionId 単位で付き合わせられる。
+export const todoAgentRendererDebug = createRendererDebugChannel({
+	namespace: "todo.agent.renderer",
+	enabled: true,
+	mirrorToConsole: isTodoAgentDebugEnabled(),
+});