fix(whatsapp): use conversation id for context isolation (#911)

Thanks @tristanmanchester.

Co-authored-by: Tristan Manchester <tmanchester96@gmail.com>

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Telegram: split long captions into media + follow-up text messages. (#907) - thanks @jalehman.
 - Slack: drop Socket Mode events with mismatched `api_app_id`/`team_id`. (#889) — thanks @roshanasingh4.
 - Discord: isolate autoThread thread context. (#856) — thanks @davidguttman.
+- WhatsApp: fix context isolation using wrong ID (was bot's number, now conversation ID). (#911) — thanks @tristanmanchester.
 
 ## 2026.1.13
 

src/auto-reply/reply/agent-runner-utils.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from "vitest";
+
+import type { ClawdbotConfig } from "../../config/config.js";
+import type { TemplateContext } from "../templating.js";
+import { buildThreadingToolContext } from "./agent-runner-utils.js";
+
+describe("buildThreadingToolContext", () => {
+  const cfg = {} as ClawdbotConfig;
+
+  it("uses conversation id for WhatsApp", () => {
+    const sessionCtx = {
+      Provider: "whatsapp",
+      From: "123@g.us",
+      To: "+15550001",
+    } as TemplateContext;
+
+    const result = buildThreadingToolContext({
+      sessionCtx,
+      config: cfg,
+      hasRepliedRef: undefined,
+    });
+
+    expect(result.currentChannelId).toBe("123@g.us");
+  });
+
+  it("uses the recipient id for other channels", () => {
+    const sessionCtx = {
+      Provider: "telegram",
+      From: "user:42",
+      To: "chat:99",
+    } as TemplateContext;
+
+    const result = buildThreadingToolContext({
+      sessionCtx,
+      config: cfg,
+      hasRepliedRef: undefined,
+    });
+
+    expect(result.currentChannelId).toBe("chat:99");
+  });
+});

src/auto-reply/reply/agent-runner-utils.ts

@@ -25,13 +25,15 @@ export function buildThreadingToolContext(params: {
   if (!provider) return {};
   const dock = getChannelDock(provider);
   if (!dock?.threading?.buildToolContext) return {};
+  // WhatsApp context isolation keys off conversation id, not the bot's own number.
+  const threadingTo = provider === "whatsapp" ? sessionCtx.From ?? sessionCtx.To : sessionCtx.To;
   return (
     dock.threading.buildToolContext({
       cfg: config,
       accountId: sessionCtx.AccountId,
       context: {
         Channel: sessionCtx.Provider,
-        To: sessionCtx.To,
+        To: threadingTo,
         ReplyToId: sessionCtx.ReplyToId,
         ThreadLabel: sessionCtx.ThreadLabel,
       },