diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94e22223e..5fe720c79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ Docs: https://docs.openclaw.ai
 - Docs/Web search: remove outdated Brave free-tier wording and replace prescriptive AI ToS guidance with neutral compliance language in Brave setup docs. (#26860) Thanks @HenryLoenwind.
 - Tools/Diffs guidance loading: move diffs usage guidance from unconditional prompt-hook injection to the plugin companion skill path, reducing unrelated-turn prompt noise while keeping diffs tool behavior unchanged. (#32630) thanks @sircrumpet.
 - Agents/tool-result truncation: preserve important tail diagnostics by using head+tail truncation for oversized tool results while keeping configurable truncation options. (#20076) thanks @jlwestsr.
+- Telegram/topic agent routing: support per-topic `agentId` overrides in forum groups and DM topics so topics can route to dedicated agents with isolated sessions. (#33647) Thanks @kesor.
 
 ### Fixes
 
diff --git a/docs/channels/telegram.md b/docs/channels/telegram.md
index c70c89ff2..9cbf7ac29 100644
--- a/docs/channels/telegram.md
+++ b/docs/channels/telegram.md
@@ -444,7 +444,8 @@ curl "https://api.telegram.org/bot<bot_token>/getUpdates"
     - message sends omit `message_thread_id` (Telegram rejects `sendMessage(...thread_id=1)`)
     - typing actions still include `message_thread_id`
 
-    Topic inheritance: topic entries inherit group settings unless overridden (`requireMention`, `allowFrom`, `skills`, `systemPrompt`, `enabled`, `groupPolicy`, `agentId`).
+    Topic inheritance: topic entries inherit group settings unless overridden (`requireMention`, `allowFrom`, `skills`, `systemPrompt`, `enabled`, `groupPolicy`).
+    `agentId` is topic-only and does not inherit from group defaults.
 
     **Per-topic agent routing**: Each topic can route to a different agent by setting `agentId` in the topic config. This gives each topic its own isolated workspace, memory, and session. Example:
 
@@ -773,7 +774,7 @@ Primary reference:
   - `channels.telegram.groups.<id>.allowFrom`: per-group sender allowlist override.
   - `channels.telegram.groups.<id>.systemPrompt`: extra system prompt for the group.
   - `channels.telegram.groups.<id>.enabled`: disable the group when `false`.
-  - `channels.telegram.groups.<id>.topics.<threadId>.*`: per-topic overrides (same fields as group).
+  - `channels.telegram.groups.<id>.topics.<threadId>.*`: per-topic overrides (group fields + topic-only `agentId`).
   - `channels.telegram.groups.<id>.topics.<threadId>.agentId`: route this topic to a specific agent (overrides group-level and binding routing).
   - `channels.telegram.groups.<id>.topics.<threadId>.groupPolicy`: per-topic override for groupPolicy (`open | allowlist | disabled`).
   - `channels.telegram.groups.<id>.topics.<threadId>.requireMention`: per-topic mention gating override.
diff --git a/src/telegram/bot-message-context.topic-agentid.test.ts b/src/telegram/bot-message-context.topic-agentid.test.ts
index 4b983670d..b3b634b47 100644
--- a/src/telegram/bot-message-context.topic-agentid.test.ts
+++ b/src/telegram/bot-message-context.topic-agentid.test.ts
@@ -1,7 +1,30 @@
-import { describe, expect, it } from "vitest";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { loadConfig } from "../config/config.js";
 import { buildTelegramMessageContextForTest } from "./bot-message-context.test-harness.js";
 
+const { defaultRouteConfig } = vi.hoisted(() => ({
+  defaultRouteConfig: {
+    agents: {
+      list: [{ id: "main", default: true }, { id: "zu" }, { id: "q" }, { id: "support" }],
+    },
+    channels: { telegram: {} },
+    messages: { groupChat: { mentionPatterns: [] } },
+  },
+}));
+
+vi.mock("../config/config.js", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("../config/config.js")>();
+  return {
+    ...actual,
+    loadConfig: vi.fn(() => defaultRouteConfig),
+  };
+});
+
 describe("buildTelegramMessageContext per-topic agentId routing", () => {
+  beforeEach(() => {
+    vi.mocked(loadConfig).mockReturnValue(defaultRouteConfig as never);
+  });
+
   it("uses group-level agent when no topic agentId is set", async () => {
     const ctx = await buildTelegramMessageContextForTest({
       message: {
@@ -120,6 +143,41 @@ describe("buildTelegramMessageContext per-topic agentId routing", () => {
     expect(ctx?.ctxPayload?.SessionKey).toContain("agent:main:");
   });
 
+  it("falls back to default agent when topic agentId does not exist", async () => {
+    vi.mocked(loadConfig).mockReturnValue({
+      agents: {
+        list: [{ id: "main", default: true }, { id: "zu" }],
+      },
+      channels: { telegram: {} },
+      messages: { groupChat: { mentionPatterns: [] } },
+    } as never);
+
+    const ctx = await buildTelegramMessageContextForTest({
+      message: {
+        message_id: 1,
+        chat: {
+          id: -1001234567890,
+          type: "supergroup",
+          title: "Forum",
+          is_forum: true,
+        },
+        date: 1700000000,
+        text: "@bot hello",
+        message_thread_id: 3,
+        from: { id: 42, first_name: "Alice" },
+      },
+      options: { forceWasMentioned: true },
+      resolveGroupActivation: () => true,
+      resolveTelegramGroupConfig: () => ({
+        groupConfig: { requireMention: false },
+        topicConfig: { agentId: "ghost" },
+      }),
+    });
+
+    expect(ctx).not.toBeNull();
+    expect(ctx?.ctxPayload?.SessionKey).toContain("agent:main:");
+  });
+
   it("routes DM topic to specific agent when agentId is set", async () => {
     const ctx = await buildTelegramMessageContextForTest({
       message: {