diff --git a/src/agent/bootstrapHandler.ts b/src/agent/bootstrapHandler.ts
new file mode 100644
index 0000000..660c4fb
--- /dev/null
+++ b/src/agent/bootstrapHandler.ts
@@ -0,0 +1,185 @@
+/**
+ * Extracted handler for the bootstrap_session_state control request.
+ *
+ * Returns a single ControlResponse containing:
+ *  - resolved session metadata (agent_id, conversation_id, model, tools, memfs_enabled)
+ *  - initial history page (messages, next_before, has_more)
+ *  - pending approval flag
+ *  - optional wall-clock timings
+ *
+ * Accepting minimal client/context interfaces keeps the handler fully testable
+ * without a real network or subprocess.
+ */
+
+import { randomUUID } from "node:crypto";
+import type {
+  BootstrapSessionStatePayload,
+  BootstrapSessionStateRequest,
+  ControlResponse,
+} from "../types/protocol";
+import { resolveListMessagesRoute } from "./listMessagesRouting";
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Minimal interfaces — only what the handler needs
+// ─────────────────────────────────────────────────────────────────────────────
+
+export interface BootstrapMessagesPage {
+  /** conversations.messages.list() returns a paginated resource */
+  getPaginatedItems(): unknown[];
+}
+
+export interface BootstrapAgentsPage {
+  items: unknown[];
+}
+
+export interface BootstrapHandlerClient {
+  conversations: {
+    messages: {
+      list(
+        conversationId: string,
+        opts: {
+          limit: number;
+          order: "asc" | "desc";
+          before?: string;
+          after?: string;
+        },
+      ): Promise<BootstrapMessagesPage>;
+    };
+  };
+  agents: {
+    messages: {
+      list(
+        agentId: string,
+        opts: {
+          limit: number;
+          order: "asc" | "desc";
+          before?: string;
+          after?: string;
+          conversation_id?: "default";
+        },
+      ): Promise<BootstrapAgentsPage>;
+    };
+  };
+}
+
+export interface BootstrapHandlerSessionContext {
+  agentId: string;
+  conversationId: string;
+  model: string | undefined;
+  tools: string[];
+  memfsEnabled: boolean;
+  sessionId: string;
+}
+
+export interface HandleBootstrapParams {
+  bootstrapReq: BootstrapSessionStateRequest;
+  sessionContext: BootstrapHandlerSessionContext;
+  requestId: string;
+  client: BootstrapHandlerClient;
+  /** Optional: flag indicating a pending approval is waiting. */
+  hasPendingApproval?: boolean;
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Handler
+// ─────────────────────────────────────────────────────────────────────────────
+
+/**
+ * Execute a bootstrap_session_state control request and return the ControlResponse.
+ *
+ * Caller is responsible for serialising + writing to stdout:
+ *   console.log(JSON.stringify(await handleBootstrapSessionState(params)));
+ */
+export async function handleBootstrapSessionState(
+  params: HandleBootstrapParams,
+): Promise<ControlResponse> {
+  const {
+    bootstrapReq,
+    sessionContext,
+    requestId,
+    client,
+    hasPendingApproval,
+  } = params;
+
+  const bootstrapStart = Date.now();
+
+  const limit = bootstrapReq.limit ?? 50;
+  const order = bootstrapReq.order ?? "desc";
+
+  try {
+    // Reuse the same routing logic as list_messages for consistency
+    const route = resolveListMessagesRoute(
+      { conversation_id: undefined, agent_id: sessionContext.agentId },
+      sessionContext.conversationId,
+      sessionContext.agentId,
+    );
+
+    const listStart = Date.now();
+    let items: unknown[];
+
+    if (route.kind === "conversations") {
+      const page = await client.conversations.messages.list(
+        route.conversationId,
+        { limit, order },
+      );
+      items = page.getPaginatedItems();
+    } else {
+      const page = await client.agents.messages.list(route.agentId, {
+        limit,
+        order,
+        conversation_id: "default",
+      });
+      items = page.items;
+    }
+    const listEnd = Date.now();
+
+    const hasMore = items.length >= limit;
+    // When order=desc, newest first; oldest item is at the end of the array.
+    const oldestId =
+      items.length > 0
+        ? (items[items.length - 1] as { id?: string })?.id
+        : undefined;
+
+    const bootstrapEnd = Date.now();
+
+    const payload: BootstrapSessionStatePayload = {
+      agent_id: sessionContext.agentId,
+      conversation_id: sessionContext.conversationId,
+      model: sessionContext.model,
+      tools: sessionContext.tools,
+      memfs_enabled: sessionContext.memfsEnabled,
+      messages: items,
+      next_before: oldestId ?? null,
+      has_more: hasMore,
+      has_pending_approval: hasPendingApproval ?? false,
+      timings: {
+        resolve_ms: listStart - bootstrapStart,
+        list_messages_ms: listEnd - listStart,
+        total_ms: bootstrapEnd - bootstrapStart,
+      },
+    };
+
+    return {
+      type: "control_response",
+      response: {
+        subtype: "success",
+        request_id: requestId,
+        response: payload as unknown as Record<string, unknown>,
+      },
+      session_id: sessionContext.sessionId,
+      uuid: randomUUID(),
+    };
+  } catch (err) {
+    return {
+      type: "control_response",
+      response: {
+        subtype: "error",
+        request_id: requestId,
+        error:
+          err instanceof Error ? err.message : "bootstrap_session_state failed",
+      },
+      session_id: sessionContext.sessionId,
+      uuid: randomUUID(),
+    };
+  }
+}
diff --git a/src/headless.ts b/src/headless.ts
index 4313d6b..007b9e9 100644
--- a/src/headless.ts
+++ b/src/headless.ts
@@ -18,6 +18,7 @@ import {
   parseRetryAfterHeaderMs,
   shouldRetryRunMetadataError,
 } from "./agent/approval-recovery";
+import { handleBootstrapSessionState } from "./agent/bootstrapHandler";
 import { getClient } from "./agent/client";
 import { setAgentContext, setConversationId } from "./agent/context";
 import { createAgent } from "./agent/create";
@@ -77,6 +78,7 @@ import {
 } from "./tools/manager";
 import type {
   AutoApprovalMessage,
+  BootstrapSessionStateRequest,
   CanUseToolControlRequest,
   CanUseToolResponse,
   ControlRequest,
@@ -286,6 +288,7 @@ export async function handleHeadlessCommand(
 
       memfs: { type: "boolean" },
       "no-memfs": { type: "boolean" },
+      "memfs-startup": { type: "string" }, // "blocking" | "background" | "skip"
       "no-skills": { type: "boolean" },
       "no-bundled-skills": { type: "boolean" },
       "no-system-info-reminder": { type: "boolean" },
@@ -436,6 +439,15 @@ export async function handleHeadlessCommand(
   const skillSourcesRaw = values["skill-sources"] as string | undefined;
   const memfsFlag = values.memfs as boolean | undefined;
   const noMemfsFlag = values["no-memfs"] as boolean | undefined;
+  // Startup policy for the git-backed memory pull on session init.
+  // "blocking" (default): await the pull before proceeding.
+  // "background": fire the pull async, emit init without waiting.
+  // "skip": skip the pull entirely this session.
+  const memfsStartupRaw = values["memfs-startup"] as string | undefined;
+  const memfsStartupPolicy: "blocking" | "background" | "skip" =
+    memfsStartupRaw === "background" || memfsStartupRaw === "skip"
+      ? memfsStartupRaw
+      : "blocking";
   const requestedMemoryPromptMode: "memfs" | "standard" | undefined = memfsFlag
     ? "memfs"
     : noMemfsFlag
@@ -955,25 +967,58 @@ export async function handleHeadlessCommand(
   const isSubagent = process.env.LETTA_CODE_AGENT_ROLE === "subagent";
 
   // Apply memfs flags and auto-enable from server tag when local settings are missing.
-  try {
-    const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
-    const memfsResult = await applyMemfsFlags(
-      agent.id,
-      memfsFlag,
-      noMemfsFlag,
-      { pullOnExistingRepo: true, agentTags: agent.tags },
-    );
-    if (memfsResult.pullSummary?.includes("CONFLICT")) {
+  // Respects memfsStartupPolicy:
+  //   "blocking"  (default) – await the pull; exit on conflict.
+  //   "background"           – fire pull async; session init proceeds immediately.
+  //   "skip"                 – skip the pull this session.
+  if (memfsStartupPolicy === "skip") {
+    // Run enable/disable logic but skip the git pull.
+    try {
+      const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
+      await applyMemfsFlags(agent.id, memfsFlag, noMemfsFlag, {
+        pullOnExistingRepo: false,
+        agentTags: agent.tags,
+      });
+    } catch (error) {
       console.error(
-        "Memory has merge conflicts. Run in interactive mode to resolve.",
+        `Memory flags failed: ${error instanceof Error ? error.message : String(error)}`,
+      );
+      process.exit(1);
+    }
+  } else if (memfsStartupPolicy === "background") {
+    // Fire pull async; don't block session initialisation.
+    const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
+    applyMemfsFlags(agent.id, memfsFlag, noMemfsFlag, {
+      pullOnExistingRepo: true,
+      agentTags: agent.tags,
+    }).catch((error) => {
+      // Log to stderr only — the session is already live.
+      console.error(
+        `[memfs background pull] ${error instanceof Error ? error.message : String(error)}`,
+      );
+    });
+  } else {
+    // "blocking" — original behaviour.
+    try {
+      const { applyMemfsFlags } = await import("./agent/memoryFilesystem");
+      const memfsResult = await applyMemfsFlags(
+        agent.id,
+        memfsFlag,
+        noMemfsFlag,
+        { pullOnExistingRepo: true, agentTags: agent.tags },
+      );
+      if (memfsResult.pullSummary?.includes("CONFLICT")) {
+        console.error(
+          "Memory has merge conflicts. Run in interactive mode to resolve.",
+        );
+        process.exit(1);
+      }
+    } catch (error) {
+      console.error(
+        `Memory git sync failed: ${error instanceof Error ? error.message : String(error)}`,
       );
       process.exit(1);
     }
-  } catch (error) {
-    console.error(
-      `Memory git sync failed: ${error instanceof Error ? error.message : String(error)}`,
-    );
-    process.exit(1);
   }
 
   try {
@@ -2711,6 +2756,23 @@ async function runBidirectionalMode(
           uuid: randomUUID(),
         };
         console.log(JSON.stringify(registerResponse));
+      } else if (subtype === "bootstrap_session_state") {
+        const bootstrapReq = message.request as BootstrapSessionStateRequest;
+        const bootstrapResp = await handleBootstrapSessionState({
+          bootstrapReq,
+          sessionContext: {
+            agentId: agent.id,
+            conversationId,
+            model: agent.llm_config?.model,
+            tools: availableTools,
+            memfsEnabled: settingsManager.isMemfsEnabled(agent.id),
+            sessionId,
+          },
+          requestId: requestId ?? "",
+          client,
+          hasPendingApproval: false, // TODO: wire approval state when available
+        });
+        console.log(JSON.stringify(bootstrapResp));
       } else if (subtype === "list_messages") {
         const listReq = message.request as ListMessagesControlRequest;
         const listResp = await handleListMessages({
diff --git a/src/tests/headless/bootstrap-handler.test.ts b/src/tests/headless/bootstrap-handler.test.ts
new file mode 100644
index 0000000..7e30f95
--- /dev/null
+++ b/src/tests/headless/bootstrap-handler.test.ts
@@ -0,0 +1,318 @@
+/**
+ * Handler-level tests for bootstrap_session_state using mock Letta clients.
+ *
+ * Verifies:
+ * 1. Correct routing (conversations vs agents path based on session conversationId)
+ * 2. Response payload shape (agent_id, conversation_id, model, tools, messages, etc.)
+ * 3. Pagination fields (next_before, has_more)
+ * 4. Timing fields presence
+ * 5. Error path — client throws → error envelope returned
+ * 6. Default conversation uses agents.messages.list with conversation_id: "default"
+ * 7. Explicit conversation uses conversations.messages.list
+ *
+ * No network. No CLI subprocess. No process.stdout.
+ */
+import { describe, expect, mock, test } from "bun:test";
+import type {
+  BootstrapHandlerClient,
+  BootstrapHandlerSessionContext,
+} from "../../agent/bootstrapHandler";
+import { handleBootstrapSessionState } from "../../agent/bootstrapHandler";
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Mock factory
+// ─────────────────────────────────────────────────────────────────────────────
+
+function makeClient(
+  convMessages: unknown[] = [],
+  agentMessages: unknown[] = [],
+): {
+  client: BootstrapHandlerClient;
+  convListSpy: ReturnType<typeof mock>;
+  agentListSpy: ReturnType<typeof mock>;
+} {
+  const convListSpy = mock(async () => ({
+    getPaginatedItems: () => convMessages,
+  }));
+  const agentListSpy = mock(async () => ({
+    items: agentMessages,
+  }));
+
+  const client: BootstrapHandlerClient = {
+    conversations: {
+      messages: {
+        list: convListSpy as unknown as BootstrapHandlerClient["conversations"]["messages"]["list"],
+      },
+    },
+    agents: {
+      messages: {
+        list: agentListSpy as unknown as BootstrapHandlerClient["agents"]["messages"]["list"],
+      },
+    },
+  };
+
+  return { client, convListSpy, agentListSpy };
+}
+
+const BASE_CTX: BootstrapHandlerSessionContext = {
+  agentId: "agent-test-123",
+  conversationId: "default",
+  model: "anthropic/claude-sonnet-4-5",
+  tools: ["Bash", "Read", "Write"],
+  memfsEnabled: false,
+  sessionId: "sess-test",
+};
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Routing
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe("bootstrap_session_state routing", () => {
+  test("default conversation uses agents.messages.list", async () => {
+    const { client, agentListSpy, convListSpy } = makeClient(
+      [],
+      [{ id: "msg-1", type: "user_message" }],
+    );
+
+    await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: { ...BASE_CTX, conversationId: "default" },
+      requestId: "req-1",
+      client,
+    });
+
+    expect(agentListSpy).toHaveBeenCalledTimes(1);
+    expect(convListSpy).toHaveBeenCalledTimes(0);
+
+    // Verify conversation_id: "default" param is passed
+    const callArgs = (agentListSpy.mock.calls[0] as unknown[])[1] as Record<
+      string,
+      unknown
+    >;
+    expect(callArgs.conversation_id).toBe("default");
+  });
+
+  test("named conversation uses conversations.messages.list", async () => {
+    const { client, convListSpy, agentListSpy } = makeClient([
+      { id: "msg-1", type: "user_message" },
+    ]);
+
+    await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: { ...BASE_CTX, conversationId: "conv-abc-123" },
+      requestId: "req-2",
+      client,
+    });
+
+    expect(convListSpy).toHaveBeenCalledTimes(1);
+    expect(agentListSpy).toHaveBeenCalledTimes(0);
+
+    const callArgs = (convListSpy.mock.calls[0] as unknown[])[0];
+    expect(callArgs).toBe("conv-abc-123");
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Response shape
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe("bootstrap_session_state response shape", () => {
+  test("success response includes all required fields", async () => {
+    const messages = [
+      { id: "msg-3", type: "assistant_message" },
+      { id: "msg-2", type: "user_message" },
+      { id: "msg-1", type: "user_message" },
+    ];
+    const { client } = makeClient([], messages);
+
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-3",
+      client,
+    });
+
+    expect(resp.type).toBe("control_response");
+    expect(resp.response.subtype).toBe("success");
+    expect(resp.response.request_id).toBe("req-3");
+    expect(resp.session_id).toBe("sess-test");
+    expect(typeof resp.uuid).toBe("string");
+
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.agent_id).toBe("agent-test-123");
+    expect(payload.conversation_id).toBe("default");
+    expect(payload.model).toBe("anthropic/claude-sonnet-4-5");
+    expect(payload.tools).toEqual(["Bash", "Read", "Write"]);
+    expect(payload.memfs_enabled).toBe(false);
+    expect(Array.isArray(payload.messages)).toBe(true);
+    expect((payload.messages as unknown[]).length).toBe(3);
+    expect(typeof payload.has_more).toBe("boolean");
+    expect(typeof payload.has_pending_approval).toBe("boolean");
+  });
+
+  test("has_pending_approval defaults to false", async () => {
+    const { client } = makeClient();
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-4",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.has_pending_approval).toBe(false);
+  });
+
+  test("has_pending_approval reflects caller-provided value", async () => {
+    const { client } = makeClient();
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-5",
+      client,
+      hasPendingApproval: true,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.has_pending_approval).toBe(true);
+  });
+
+  test("timings are present and numeric", async () => {
+    const { client } = makeClient();
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-6",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    const timings = payload.timings as Record<string, unknown>;
+    expect(typeof timings).toBe("object");
+    expect(typeof timings.resolve_ms).toBe("number");
+    expect(typeof timings.list_messages_ms).toBe("number");
+    expect(typeof timings.total_ms).toBe("number");
+    // Sanity: total_ms >= list_messages_ms
+    expect(timings.total_ms as number).toBeGreaterThanOrEqual(
+      timings.list_messages_ms as number,
+    );
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Pagination
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe("bootstrap_session_state pagination", () => {
+  test("has_more is false when messages < limit", async () => {
+    const messages = Array.from({ length: 5 }, (_, i) => ({
+      id: `msg-${i}`,
+      type: "user_message",
+    }));
+    const { client } = makeClient([], messages);
+
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state", limit: 50 },
+      sessionContext: BASE_CTX,
+      requestId: "req-7",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.has_more).toBe(false);
+  });
+
+  test("has_more is true when messages === limit", async () => {
+    const limit = 10;
+    const messages = Array.from({ length: limit }, (_, i) => ({
+      id: `msg-${i}`,
+    }));
+    const { client } = makeClient([], messages);
+
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state", limit },
+      sessionContext: BASE_CTX,
+      requestId: "req-8",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.has_more).toBe(true);
+  });
+
+  test("next_before is last message id when messages present", async () => {
+    const messages = [
+      { id: "msg-newest" },
+      { id: "msg-middle" },
+      { id: "msg-oldest" },
+    ];
+    const { client } = makeClient([], messages);
+
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-9",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    // Last item in array is oldest when order=desc
+    expect(payload.next_before).toBe("msg-oldest");
+  });
+
+  test("next_before is null when no messages", async () => {
+    const { client } = makeClient([], []);
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-10",
+      client,
+    });
+    const payload = (resp.response as { response: Record<string, unknown> })
+      .response;
+    expect(payload.next_before).toBeNull();
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Error path
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe("bootstrap_session_state error handling", () => {
+  test("client error returns error envelope", async () => {
+    const throwingClient: BootstrapHandlerClient = {
+      conversations: {
+        messages: {
+          list: async () => {
+            throw new Error("Network timeout");
+          },
+        },
+      },
+      agents: {
+        messages: {
+          list: async () => {
+            throw new Error("Network timeout");
+          },
+        },
+      },
+    };
+
+    const resp = await handleBootstrapSessionState({
+      bootstrapReq: { subtype: "bootstrap_session_state" },
+      sessionContext: BASE_CTX,
+      requestId: "req-err",
+      client: throwingClient,
+    });
+
+    expect(resp.type).toBe("control_response");
+    expect(resp.response.subtype).toBe("error");
+    const errorResp = resp.response as {
+      subtype: "error";
+      error: string;
+      request_id: string;
+    };
+    expect(errorResp.error).toContain("Network timeout");
+    expect(errorResp.request_id).toBe("req-err");
+  });
+});
diff --git a/src/types/protocol.ts b/src/types/protocol.ts
index e1ef358..4163553 100644
--- a/src/types/protocol.ts
+++ b/src/types/protocol.ts
@@ -271,8 +271,55 @@ export type SdkToCliControlRequest =
   | { subtype: "initialize" }
   | { subtype: "interrupt" }
   | RegisterExternalToolsRequest
+  | BootstrapSessionStateRequest
   | ListMessagesControlRequest;
 
+/**
+ * Request to bootstrap session state (SDK → CLI).
+ * Returns resolved session metadata, initial history page, and optional pending
+ * approval snapshot — all in a single round-trip to minimise cold-open latency.
+ */
+export interface BootstrapSessionStateRequest {
+  subtype: "bootstrap_session_state";
+  /** Max messages to include in the initial history page. Defaults to 50. */
+  limit?: number;
+  /** Sort order for initial history page. Defaults to "desc". */
+  order?: "asc" | "desc";
+}
+
+/**
+ * Successful bootstrap_session_state response payload.
+ */
+export interface BootstrapSessionStatePayload {
+  /** Resolved agent ID for this session. */
+  agent_id: string;
+  /** Resolved conversation ID for this session. */
+  conversation_id: string;
+  /** LLM model handle. */
+  model: string | undefined;
+  /** Tool names registered on the agent. */
+  tools: string[];
+  /** Whether memfs (git-backed memory) is enabled. */
+  memfs_enabled: boolean;
+  /** Initial history page (same shape as list_messages response). */
+  messages: unknown[];
+  /** Cursor to fetch older messages (null if none). */
+  next_before: string | null;
+  /** Whether more history pages exist. */
+  has_more: boolean;
+  /** Whether there is a pending approval waiting for a response. */
+  has_pending_approval: boolean;
+  /** Optional wall-clock timings in milliseconds. */
+  timings?: {
+    /** Time to resolve agent + conversation context. */
+    resolve_ms: number;
+    /** Time to fetch the initial message page. */
+    list_messages_ms: number;
+    /** Total bootstrap wall-clock time. */
+    total_ms: number;
+  };
+}
+
 /**
  * Request to list conversation messages (SDK → CLI).
  * Returns paginated messages from a specific conversation.