diff --git a/src/imessage/client.ts b/src/imessage/client.ts
index 070765e3b..1a47f1726 100644
--- a/src/imessage/client.ts
+++ b/src/imessage/client.ts
@@ -2,6 +2,7 @@ import { type ChildProcessWithoutNullStreams, spawn } from "node:child_process";
 import { createInterface, type Interface } from "node:readline";
 import type { RuntimeEnv } from "../runtime.js";
 import { resolveUserPath } from "../utils.js";
+import { DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS } from "./constants.js";
 
 export type IMessageRpcError = {
   code?: number;
@@ -149,8 +150,7 @@ export class IMessageRpcClient {
       params: params ?? {},
     };
     const line = `${JSON.stringify(payload)}\n`;
-    // Default timeout matches DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS from probe.ts
-    const timeoutMs = opts?.timeoutMs ?? 10_000;
+    const timeoutMs = opts?.timeoutMs ?? DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS;
 
     const response = new Promise<T>((resolve, reject) => {
       const key = String(id);
diff --git a/src/imessage/constants.ts b/src/imessage/constants.ts
new file mode 100644
index 000000000..d82eaa502
--- /dev/null
+++ b/src/imessage/constants.ts
@@ -0,0 +1,2 @@
+/** Default timeout for iMessage probe/RPC operations (10 seconds). */
+export const DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS = 10_000;
diff --git a/src/imessage/monitor/monitor-provider.ts b/src/imessage/monitor/monitor-provider.ts
index 1f6c457f3..9044f221b 100644
--- a/src/imessage/monitor/monitor-provider.ts
+++ b/src/imessage/monitor/monitor-provider.ts
@@ -45,7 +45,8 @@ import { resolveAgentRoute } from "../../routing/resolve-route.js";
 import { truncateUtf16Safe } from "../../utils.js";
 import { resolveIMessageAccount } from "../accounts.js";
 import { createIMessageRpcClient } from "../client.js";
-import { DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS, probeIMessage } from "../probe.js";
+import { DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS } from "../constants.js";
+import { probeIMessage } from "../probe.js";
 import { sendMessageIMessage } from "../send.js";
 import {
   formatIMessageChatTarget,
diff --git a/src/imessage/probe.ts b/src/imessage/probe.ts
index 5df7c667d..9226d48b1 100644
--- a/src/imessage/probe.ts
+++ b/src/imessage/probe.ts
@@ -3,9 +3,10 @@ import { detectBinary } from "../commands/onboard-helpers.js";
 import { loadConfig } from "../config/config.js";
 import { runCommandWithTimeout } from "../process/exec.js";
 import { createIMessageRpcClient } from "./client.js";
+import { DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS } from "./constants.js";
 
-/** Default timeout for iMessage probe operations (10 seconds). */
-export const DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS = 10_000;
+// Re-export for backwards compatibility
+export { DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS } from "./constants.js";
 
 export type IMessageProbe = {
   ok: boolean;
@@ -59,18 +60,21 @@ async function probeRpcSupport(cliPath: string, timeoutMs: number): Promise<RpcS
   }
 }
 
+/**
+ * Probe iMessage RPC availability.
+ * @param timeoutMs - Explicit timeout in ms. If undefined, uses config or default.
+ * @param opts - Additional options (cliPath, dbPath, runtime).
+ */
 export async function probeIMessage(
-  timeoutMs = DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS,
+  timeoutMs?: number,
   opts: IMessageProbeOptions = {},
 ): Promise<IMessageProbe> {
   const cfg = opts.cliPath || opts.dbPath ? undefined : loadConfig();
   const cliPath = opts.cliPath?.trim() || cfg?.channels?.imessage?.cliPath?.trim() || "imsg";
   const dbPath = opts.dbPath?.trim() || cfg?.channels?.imessage?.dbPath?.trim();
-  // Read probeTimeoutMs from config if not explicitly provided
+  // Use explicit timeout if provided, otherwise fall back to config, then default
   const effectiveTimeout =
-    timeoutMs !== DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS
-      ? timeoutMs
-      : cfg?.channels?.imessage?.probeTimeoutMs ?? DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS;
+    timeoutMs ?? cfg?.channels?.imessage?.probeTimeoutMs ?? DEFAULT_IMESSAGE_PROBE_TIMEOUT_MS;
 
   const detected = await detectBinary(cliPath);
   if (!detected) {