diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b0583114..294c64aaf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -57,6 +57,7 @@
 
 #### Messaging / Channels
 - Messaging: unify markdown formatting + format-first chunking for Slack/Telegram/Signal. (#920) — thanks @TheSethRose.
+- iMessage: prefer handle routing for direct-message replies; include imsg RPC error details. (#935)
 - Slack: respect `channels.slack.requireMention` default when resolving channel mention gating. (#850) — thanks @evalexpr.
 - Slack: drop Socket Mode events with mismatched `api_app_id`/`team_id`. (#889) — thanks @roshanasingh4.
 - Discord: isolate autoThread thread context. (#856) — thanks @davidguttman.
diff --git a/src/auto-reply/reply/agent-runner-utils.test.ts b/src/auto-reply/reply/agent-runner-utils.test.ts
index f51f90f31..08741fac9 100644
--- a/src/auto-reply/reply/agent-runner-utils.test.ts
+++ b/src/auto-reply/reply/agent-runner-utils.test.ts
@@ -53,4 +53,38 @@ describe("buildThreadingToolContext", () => {
 
     expect(result.currentChannelId).toBe("chat:99");
   });
+
+  it("uses the sender handle for iMessage direct chats", () => {
+    const sessionCtx = {
+      Provider: "imessage",
+      ChatType: "direct",
+      From: "imessage:+15550001",
+      To: "chat_id:12",
+    } as TemplateContext;
+
+    const result = buildThreadingToolContext({
+      sessionCtx,
+      config: cfg,
+      hasRepliedRef: undefined,
+    });
+
+    expect(result.currentChannelId).toBe("imessage:+15550001");
+  });
+
+  it("uses chat_id for iMessage groups", () => {
+    const sessionCtx = {
+      Provider: "imessage",
+      ChatType: "group",
+      From: "group:7",
+      To: "chat_id:7",
+    } as TemplateContext;
+
+    const result = buildThreadingToolContext({
+      sessionCtx,
+      config: cfg,
+      hasRepliedRef: undefined,
+    });
+
+    expect(result.currentChannelId).toBe("chat_id:7");
+  });
 });
diff --git a/src/auto-reply/reply/agent-runner-utils.ts b/src/auto-reply/reply/agent-runner-utils.ts
index 5f5d1ca18..4f955b8aa 100644
--- a/src/auto-reply/reply/agent-runner-utils.ts
+++ b/src/auto-reply/reply/agent-runner-utils.ts
@@ -26,7 +26,12 @@ export function buildThreadingToolContext(params: {
   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;
+  const threadingTo =
+    provider === "whatsapp"
+      ? (sessionCtx.From ?? sessionCtx.To)
+      : provider === "imessage" && sessionCtx.ChatType === "direct"
+        ? (sessionCtx.From ?? sessionCtx.To)
+        : sessionCtx.To;
   return (
     dock.threading.buildToolContext({
       cfg: config,
diff --git a/src/imessage/client.ts b/src/imessage/client.ts
index 94b391dab..52d255ad8 100644
--- a/src/imessage/client.ts
+++ b/src/imessage/client.ts
@@ -180,7 +180,17 @@ export class IMessageRpcClient {
       this.pending.delete(key);
 
       if (parsed.error) {
-        const msg = parsed.error.message ?? "imsg rpc error";
+        const baseMessage = parsed.error.message ?? "imsg rpc error";
+        const details = parsed.error.data;
+        const code = parsed.error.code;
+        const suffixes = [] as string[];
+        if (typeof code === "number") suffixes.push(`code=${code}`);
+        if (details !== undefined) {
+          const detailText =
+            typeof details === "string" ? details : JSON.stringify(details, null, 2);
+          if (detailText) suffixes.push(detailText);
+        }
+        const msg = suffixes.length > 0 ? `${baseMessage}: ${suffixes.join(" ")}` : baseMessage;
         pending.reject(new Error(msg));
         return;
       }
diff --git a/src/imessage/monitor.updates-last-route-chat-id-direct-messages.test.ts b/src/imessage/monitor.updates-last-route-chat-id-direct-messages.test.ts
index c5d2bf929..49e739f1f 100644
--- a/src/imessage/monitor.updates-last-route-chat-id-direct-messages.test.ts
+++ b/src/imessage/monitor.updates-last-route-chat-id-direct-messages.test.ts
@@ -92,7 +92,7 @@ beforeEach(() => {
 });
 
 describe("monitorIMessageProvider", () => {
-  it("updates last route with chat_id for direct messages", async () => {
+  it("updates last route with sender handle for direct messages", async () => {
     replyMock.mockResolvedValueOnce({ text: "ok" });
     const run = monitorIMessageProvider();
     await waitForSubscribe();
@@ -118,7 +118,7 @@ describe("monitorIMessageProvider", () => {
     expect(updateLastRouteMock).toHaveBeenCalledWith(
       expect.objectContaining({
         channel: "imessage",
-        to: "chat_id:7",
+        to: "+15550004444",
       }),
     );
   });
diff --git a/src/imessage/monitor/monitor-provider.ts b/src/imessage/monitor/monitor-provider.ts
index 1d86ec993..be98db0a4 100644
--- a/src/imessage/monitor/monitor-provider.ts
+++ b/src/imessage/monitor/monitor-provider.ts
@@ -296,7 +296,7 @@ export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): P
       });
     }
 
-    const imessageTo = chatTarget || `imessage:${sender}`;
+    const imessageTo = (isGroup ? chatTarget : undefined) || `imessage:${sender}`;
     const ctxPayload = {
       Body: combinedBody,
       RawBody: bodyText,
@@ -329,7 +329,7 @@ export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): P
       const storePath = resolveStorePath(sessionCfg?.store, {
         agentId: route.agentId,
       });
-      const to = chatTarget || sender;
+      const to = (isGroup ? chatTarget : undefined) || sender;
       if (to) {
         await updateLastRoute({
           storePath,
diff --git a/src/infra/outbound/message-action-runner.test.ts b/src/infra/outbound/message-action-runner.test.ts
index 58954e205..c3b027107 100644
--- a/src/infra/outbound/message-action-runner.test.ts
+++ b/src/infra/outbound/message-action-runner.test.ts
@@ -100,4 +100,36 @@ describe("runMessageAction context isolation", () => {
       }),
     ).rejects.toThrow(/Cross-context messaging denied/);
   });
+
+  it("allows iMessage send when target matches current handle", async () => {
+    const result = await runMessageAction({
+      cfg: whatsappConfig,
+      action: "send",
+      params: {
+        channel: "imessage",
+        to: "imessage:+15551234567",
+        message: "hi",
+      },
+      toolContext: { currentChannelId: "imessage:+15551234567" },
+      dryRun: true,
+    });
+
+    expect(result.kind).toBe("send");
+  });
+
+  it("blocks iMessage send when target differs from current handle", async () => {
+    await expect(
+      runMessageAction({
+        cfg: whatsappConfig,
+        action: "send",
+        params: {
+          channel: "imessage",
+          to: "imessage:+15551230000",
+          message: "hi",
+        },
+        toolContext: { currentChannelId: "imessage:+15551234567" },
+        dryRun: true,
+      }),
+    ).rejects.toThrow(/Cross-context messaging denied/);
+  });
 });