diff --git a/src/channel/openclaw-sdk-untyped.d.ts b/src/channel/openclaw-sdk-untyped.d.ts
index 3e9aea8..ad2954a 100644
--- a/src/channel/openclaw-sdk-untyped.d.ts
+++ b/src/channel/openclaw-sdk-untyped.d.ts
@@ -35,8 +35,6 @@ declare module "openclaw/plugin-sdk/plugin-state-runtime" {
 declare module "openclaw/plugin-sdk/web-content-extractor" {
   /** Converts sanitized HTML into coarse markdown plus an optional title. */
   export function htmlToMarkdown(html: string): { text: string; title?: string };
-  /** Removes markdown decoration for plain text extraction. */
-  export function markdownToText(markdown: string): string;
 }
 
 declare module "openclaw/plugin-sdk/outbound-media" {
diff --git a/src/channel/src/inbound-sdk-compat.test.ts b/src/channel/src/inbound-sdk-compat.test.ts
new file mode 100644
index 0000000..6dc0772
--- /dev/null
+++ b/src/channel/src/inbound-sdk-compat.test.ts
@@ -0,0 +1,51 @@
+import type { AgentMail } from "agentmail";
+import { describe, expect, it, vi } from "vitest";
+
+// OpenClaw 2026.10.5-beta.2 no longer exports markdownToText from this SDK subpath.
+vi.mock("openclaw/plugin-sdk/web-content-extractor", async (importOriginal) => {
+  const { htmlToMarkdown } =
+    await importOriginal<typeof import("openclaw/plugin-sdk/web-content-extractor")>();
+  return { htmlToMarkdown };
+});
+
+import { resolveAgentMailMessageText } from "./inbound.js";
+
+describe("AgentMail HTML with the current OpenClaw SDK exports", () => {
+  it.each(["extractedHtml", "html"] as const)("converts %s without markdownToText", (field) => {
+    const message = {
+      [field]: '<h2>Next steps</h2><ul><li>Read <a href="https://example.com/guide">the guide</a></li></ul>',
+    } as AgentMail.Message;
+
+    expect(resolveAgentMailMessageText(message)).toBe(
+      "## Next steps\n\n- Read [the guide](https://example.com/guide)",
+    );
+  });
+
+  it("prefers extracted HTML over quoted plain-text history", () => {
+    expect(
+      resolveAgentMailMessageText({
+        extractedHtml: "<p>New reply</p>",
+        text: "New reply\n\nOld quoted history",
+        html: "<p>Old HTML history</p>",
+      } as AgentMail.Message),
+    ).toBe("New reply");
+  });
+
+  it("falls back to plain text when extracted HTML has no visible content", () => {
+    expect(
+      resolveAgentMailMessageText({
+        extractedHtml: "<script>hidden()</script>",
+        text: "Plain-text reply",
+      } as AgentMail.Message),
+    ).toBe("Plain-text reply");
+  });
+
+  it("falls back to the subject when HTML has no visible content", () => {
+    expect(
+      resolveAgentMailMessageText({
+        html: "<script>hidden()</script>",
+        subject: " Subject-only request ",
+      } as AgentMail.Message),
+    ).toBe("Subject-only request");
+  });
+});
diff --git a/src/channel/src/inbound.ts b/src/channel/src/inbound.ts
index 2d46ccb..a9d1674 100644
--- a/src/channel/src/inbound.ts
+++ b/src/channel/src/inbound.ts
@@ -3,7 +3,7 @@ import { AgentMailError, type AgentMail, type AgentMailClient } from "agentmail"
 import type { OpenClawConfig } from "openclaw/plugin-sdk/config-contracts";
 import type { PluginRuntime } from "openclaw/plugin-sdk/plugin-runtime";
 import { buildAgentSessionKey, parseAgentSessionKey } from "openclaw/plugin-sdk/routing";
-import { htmlToMarkdown, markdownToText } from "openclaw/plugin-sdk/web-content-extractor";
+import { htmlToMarkdown } from "openclaw/plugin-sdk/web-content-extractor";
 import type { AgentMailLog } from "./log.js";
 import { createAgentMailClient } from "./client.js";
 import { isAgentMailSenderAllowed, parseSingleFromMailbox } from "./mailbox.js";
@@ -135,7 +135,7 @@ export function resolveAgentMailMessageText(message: AgentMail.Message): string
   }
   const extractedHtml = message.extractedHtml?.trim();
   const extractedHtmlText = extractedHtml
-    ? markdownToText(htmlToMarkdown(extractedHtml).text).trim()
+    ? htmlToMarkdown(extractedHtml).text.trim()
     : "";
   if (extractedHtmlText) {
     return extractedHtmlText;
@@ -145,7 +145,7 @@ export function resolveAgentMailMessageText(message: AgentMail.Message): string
     return text;
   }
   const html = message.html?.trim();
-  const htmlText = html ? markdownToText(htmlToMarkdown(html).text).trim() : "";
+  const htmlText = html ? htmlToMarkdown(html).text.trim() : "";
   return htmlText || message.subject?.trim() || "";
 }