diff --git a/extensions/acpx/src/pi-session-catalog-plugin.ts b/extensions/acpx/src/pi-session-catalog-plugin.ts
index b2e91e6b77f9..e130e80f9af1 100644
--- a/extensions/acpx/src/pi-session-catalog-plugin.ts
+++ b/extensions/acpx/src/pi-session-catalog-plugin.ts
@@ -19,6 +19,7 @@ import type {
   SessionsCatalogReadResult,
 } from "openclaw/plugin-sdk/session-catalog";
 import { isRecord } from "openclaw/plugin-sdk/string-coerce-runtime";
+import { truncateUtf16Safe } from "openclaw/plugin-sdk/text-utility-runtime";
 import {
   listLocalPiSessionPage,
   optionalPiString,
@@ -241,7 +242,7 @@ async function listPiNodeHost(
       params: {
         ...(query.limitPerHost ? { limit: query.limitPerHost } : {}),
         ...(query.search?.trim()
-          ? { searchTerm: query.search.trim().slice(0, MAX_SEARCH_LENGTH) }
+          ? { searchTerm: truncateUtf16Safe(query.search.trim(), MAX_SEARCH_LENGTH) }
           : {}),
         ...(query.cursors?.[hostId] ? { cursor: query.cursors[hostId] } : {}),
       },
@@ -310,7 +311,9 @@ async function listPiHosts(
   query: Parameters<SessionCatalogProvider["list"]>[0],
 ): Promise<SessionCatalogHost[]> {
   const requested = query.hostIds ? new Set(query.hostIds) : undefined;
-  const searchTerm = query.search?.trim().slice(0, MAX_SEARCH_LENGTH) || undefined;
+  const searchTerm = query.search
+    ? truncateUtf16Safe(query.search.trim(), MAX_SEARCH_LENGTH) || undefined
+    : undefined;
   const hosts: SessionCatalogHost[] = [];
   if ((!requested || requested.has(LOCAL_HOST_ID)) && piSessionStoreAvailable(process.env)) {
     try {
diff --git a/extensions/acpx/src/pi-session-catalog.test.ts b/extensions/acpx/src/pi-session-catalog.test.ts
index 73c4cee2d345..f008536fa753 100644
--- a/extensions/acpx/src/pi-session-catalog.test.ts
+++ b/extensions/acpx/src/pi-session-catalog.test.ts
@@ -32,6 +32,10 @@ import { piSessionStore } from "./pi-session-paths.js";
 const PI_SESSIONS_LIST_COMMAND = "acpx.pi.sessions.list.v1";
 const PI_SESSION_READ_COMMAND = "acpx.pi.sessions.read.v1";
 const PI_TERMINAL_RESUME_COMMAND = "acpx.pi.terminal.resume.v1";
+const UTF16_SEARCH_PREFIX = "x".repeat(499);
+const UTF16_BOUNDARY_SEARCH = `${UTF16_SEARCH_PREFIX}😀`;
+const LONE_SURROGATE_PATTERN =
+  /[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]/u;
 
 const temporaryDirectories: string[] = [];
 const originalSessionDir = process.env.PI_CODING_AGENT_SESSION_DIR;
@@ -40,7 +44,10 @@ const originalHome = process.env.HOME;
 const originalUserProfile = process.env.USERPROFILE;
 const originalPath = process.env.PATH;
 
-async function createPiStore(assistantText = "hi"): Promise<string> {
+async function createPiStore(
+  assistantText = "hi",
+  sessionName = "Pi catalog session",
+): Promise<string> {
   const directory = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-pi-catalog-"));
   temporaryDirectories.push(directory);
   process.env.PI_CODING_AGENT_SESSION_DIR = directory;
@@ -94,7 +101,7 @@ async function createPiStore(assistantText = "hi"): Promise<string> {
       id: "info-1",
       parentId: "tool-1",
       timestamp: "2026-07-13T10:00:04.000Z",
-      name: "Pi catalog session",
+      name: sessionName,
     },
   ];
   await fs.writeFile(
@@ -276,6 +283,32 @@ describe("Pi session catalog", () => {
     ]);
   });
 
+  it("keeps local search needles UTF-16 safe at the length limit", async () => {
+    await createPiStore("hi", UTF16_SEARCH_PREFIX);
+    let provider: Parameters<OpenClawPluginApi["registerSessionCatalog"]>[0] | undefined;
+    registerPiSessionCatalog({
+      pluginConfig: {},
+      runtime: { nodes: { list: vi.fn().mockResolvedValue({ nodes: [] }) } },
+      registerSessionCatalog: (value: NonNullable<typeof provider>) => {
+        provider = value;
+      },
+      registerNodeHostCommand: vi.fn(),
+      registerNodeInvokePolicy: vi.fn(),
+    } as unknown as OpenClawPluginApi);
+
+    await expect(
+      provider!.list({ hostIds: ["gateway"], search: UTF16_BOUNDARY_SEARCH }),
+    ).resolves.toEqual([
+      expect.objectContaining({
+        hostId: "gateway",
+        sessions: [expect.objectContaining({ threadId: "pi-session", name: UTF16_SEARCH_PREFIX })],
+      }),
+    ]);
+    await expect(
+      provider!.list({ hostIds: ["gateway"], search: `${"y".repeat(499)}😀` }),
+    ).resolves.toEqual([expect.objectContaining({ hostId: "gateway", sessions: [] })]);
+  });
+
   it("summarizes and pages a large session within transport limits", async () => {
     await createPiStore("x".repeat(600 * 1024));
     const listed = await listLocalPiSessionPage({ limit: 20 });
@@ -735,11 +768,24 @@ describe("Pi session catalog", () => {
       registerNodeInvokePolicy: vi.fn(),
     } as unknown as OpenClawPluginApi);
 
-    await expect(provider!.list({ hostIds: ["node:node-1"] })).resolves.toEqual([
+    await expect(
+      provider!.list({ hostIds: ["node:node-1"], search: UTF16_BOUNDARY_SEARCH }),
+    ).resolves.toEqual([
       expect.objectContaining({
         sessions: [expect.objectContaining({ threadId: "pi-remote", canOpenTerminal: true })],
       }),
     ]);
+    expect(invoke).toHaveBeenNthCalledWith(1, {
+      nodeId: "node-1",
+      command: PI_SESSIONS_LIST_COMMAND,
+      params: { searchTerm: UTF16_SEARCH_PREFIX },
+      timeoutMs: 20_000,
+      scopes: ["operator.write"],
+    });
+    const firstRequest = invoke.mock.calls[0]?.[0] as
+      | { params?: { searchTerm?: string } }
+      | undefined;
+    expect(firstRequest?.params?.searchTerm).not.toMatch(LONE_SURROGATE_PATTERN);
     await expect(
       provider!.openTerminal!({ hostId: "node:node-1", threadId: "pi-remote" }),
     ).resolves.toEqual({
diff --git a/extensions/opencode/session-catalog-plugin.ts b/extensions/opencode/session-catalog-plugin.ts
index 0901a3c37b33..54a3efb55db1 100644
--- a/extensions/opencode/session-catalog-plugin.ts
+++ b/extensions/opencode/session-catalog-plugin.ts
@@ -16,6 +16,7 @@ import type {
   SessionsCatalogReadResult,
 } from "openclaw/plugin-sdk/session-catalog";
 import { isRecord } from "openclaw/plugin-sdk/string-coerce-runtime";
+import { truncateUtf16Safe } from "openclaw/plugin-sdk/text-utility-runtime";
 import {
   OPENCODE_LOCAL_SESSION_HOST_ID as LOCAL_HOST_ID,
   OPENCODE_NODE_INVOKE_TIMEOUT_MS as NODE_TIMEOUT_MS,
@@ -244,7 +245,7 @@ async function listOpenCodeNodeHost(
       params: {
         ...(query.limitPerHost ? { limit: query.limitPerHost } : {}),
         ...(query.search?.trim()
-          ? { searchTerm: query.search.trim().slice(0, MAX_SEARCH_LENGTH) }
+          ? { searchTerm: truncateUtf16Safe(query.search.trim(), MAX_SEARCH_LENGTH) }
           : {}),
         ...(query.cursors?.[hostId] ? { cursor: query.cursors[hostId] } : {}),
       },
@@ -316,7 +317,9 @@ async function listOpenCodeHosts(
   query: Parameters<SessionCatalogProvider["list"]>[0],
 ): Promise<SessionCatalogHost[]> {
   const requested = query.hostIds ? new Set(query.hostIds) : undefined;
-  const searchTerm = query.search?.trim().slice(0, MAX_SEARCH_LENGTH) || undefined;
+  const searchTerm = query.search
+    ? truncateUtf16Safe(query.search.trim(), MAX_SEARCH_LENGTH) || undefined
+    : undefined;
   const hosts: SessionCatalogHost[] = [];
   if (
     (!requested || requested.has(LOCAL_HOST_ID)) &&
diff --git a/extensions/opencode/session-catalog.test.ts b/extensions/opencode/session-catalog.test.ts
index 880baf1d0a01..803dbf774432 100644
--- a/extensions/opencode/session-catalog.test.ts
+++ b/extensions/opencode/session-catalog.test.ts
@@ -39,17 +39,24 @@ import {
   readLocalOpenCodeTranscriptPage,
 } from "./session-catalog.js";
 
+const UTF16_SEARCH_PREFIX = "x".repeat(499);
+const UTF16_BOUNDARY_SEARCH = `${UTF16_SEARCH_PREFIX}😀`;
+const LONE_SURROGATE_PATTERN =
+  /[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]/u;
 const temporaryDirectories: string[] = [];
 const originalPath = process.env.PATH;
 const originalUnrelatedEnv = process.env.CATALOG_UNRELATED_ENV;
 
-async function installFakeOpenCode(assistantText = "hi"): Promise<string> {
+async function installFakeOpenCode(
+  assistantText = "hi",
+  sessionTitle = "Catalog session",
+): Promise<string> {
   const directory = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-opencode-catalog-"));
   temporaryDirectories.push(directory);
   const executable = path.join(directory, "opencode");
   const session = {
     id: "ses_test",
-    title: "Catalog session",
+    title: sessionTitle,
     created: 1_700_000_000_000,
     updated: 1_700_000_001_000,
     projectId: "project",
@@ -196,6 +203,35 @@ describe("OpenCode session catalog", () => {
     },
   );
 
+  it.runIf(process.platform !== "win32")(
+    "keeps local search needles UTF-16 safe at the length limit",
+    async () => {
+      await installFakeOpenCode("hi", UTF16_SEARCH_PREFIX);
+      let provider: Parameters<OpenClawPluginApi["registerSessionCatalog"]>[0] | undefined;
+      registerOpenCodeSessionCatalog({
+        pluginConfig: {},
+        runtime: { nodes: { list: vi.fn().mockResolvedValue({ nodes: [] }) } },
+        registerSessionCatalog: (value: NonNullable<typeof provider>) => {
+          provider = value;
+        },
+        registerNodeHostCommand: vi.fn(),
+        registerNodeInvokePolicy: vi.fn(),
+      } as unknown as OpenClawPluginApi);
+
+      await expect(
+        provider!.list({ hostIds: ["gateway"], search: UTF16_BOUNDARY_SEARCH }),
+      ).resolves.toEqual([
+        expect.objectContaining({
+          hostId: "gateway",
+          sessions: [expect.objectContaining({ threadId: "ses_test", name: UTF16_SEARCH_PREFIX })],
+        }),
+      ]);
+      await expect(
+        provider!.list({ hostIds: ["gateway"], search: `${"y".repeat(499)}😀` }),
+      ).resolves.toEqual([expect.objectContaining({ hostId: "gateway", sessions: [] })]);
+    },
+  );
+
   it.runIf(process.platform !== "win32")(
     "keeps oversized transcript items below the node payload budget",
     async () => {
@@ -368,11 +404,24 @@ describe("OpenCode session catalog", () => {
       registerNodeInvokePolicy: vi.fn(),
     } as unknown as OpenClawPluginApi);
 
-    await expect(provider!.list({ hostIds: ["node:node-1"] })).resolves.toEqual([
+    await expect(
+      provider!.list({ hostIds: ["node:node-1"], search: UTF16_BOUNDARY_SEARCH }),
+    ).resolves.toEqual([
       expect.objectContaining({
         sessions: [expect.objectContaining({ threadId: "ses_remote", canOpenTerminal: true })],
       }),
     ]);
+    expect(invoke).toHaveBeenNthCalledWith(1, {
+      nodeId: "node-1",
+      command: OPENCODE_SESSIONS_LIST_COMMAND,
+      params: { searchTerm: UTF16_SEARCH_PREFIX },
+      timeoutMs: 35_000,
+      scopes: ["operator.write"],
+    });
+    const firstRequest = invoke.mock.calls[0]?.[0] as
+      | { params?: { searchTerm?: string } }
+      | undefined;
+    expect(firstRequest?.params?.searchTerm).not.toMatch(LONE_SURROGATE_PATTERN);
     await expect(
       provider!.openTerminal!({ hostId: "node:node-1", threadId: "ses_remote" }),
     ).resolves.toEqual({