diff --git a/src/hooks/session-recovery/recover-unavailable-tool.ts b/src/hooks/session-recovery/recover-unavailable-tool.ts
index 01c6660c9..2b8cf0702 100644
--- a/src/hooks/session-recovery/recover-unavailable-tool.ts
+++ b/src/hooks/session-recovery/recover-unavailable-tool.ts
@@ -21,6 +21,17 @@ interface PromptWithToolResultInput {
   body: { parts: ToolResultPart[] }
 }
 
+type ClientWithPromptAsync = Client & {
+  session: Client["session"] & {
+    promptAsync: (input: PromptWithToolResultInput) => Promise<unknown>
+  }
+}
+
+function hasPromptAsync(client: Client): client is ClientWithPromptAsync {
+  const promptAsync = (client.session as { promptAsync?: unknown }).promptAsync
+  return typeof promptAsync === "function"
+}
+
 interface ToolUsePart {
   type: "tool_use"
   id: string
@@ -104,17 +115,12 @@ export async function recoverUnavailableTool(
       path: { id: sessionID },
       body: { parts: toolResultParts },
     }
-    const promptAsync = client.session.promptAsync as (...args: never[]) => unknown
-    const promptClient = {
-      session: {
-        status: client.session.status,
-        promptAsync: (input: PromptWithToolResultInput) => (
-          Reflect.apply(promptAsync, client.session, [input]) as Promise<unknown>
-        ),
-      },
+    if (!hasPromptAsync(client)) {
+      return false
     }
+
     const promptResult = await promptAsyncAfterSessionIdle<PromptWithToolResultInput>({
-      client: promptClient,
+      client,
       sessionID,
       source: "session-recovery-unavailable-tool",
       input: promptInput,
diff --git a/src/shared/prompt-async-route-audit.test.ts b/src/shared/prompt-async-route-audit.test.ts
index 0335b7c47..32b00f88b 100644
--- a/src/shared/prompt-async-route-audit.test.ts
+++ b/src/shared/prompt-async-route-audit.test.ts
@@ -42,6 +42,14 @@ describe("production prompt injection routes", () => {
     // given
     const files = await listSourceFiles(SOURCE_ROOT)
     const offenders: string[] = []
+    const rawPromptPatterns = [
+      /\bsession\.promptAsync\s*\(/,
+      /\bsession\.prompt\s*\(/,
+      /\bReflect\.apply\s*\(\s*\w*promptAsync\b/,
+      /\bReflect\.apply\s*\(\s*\w*prompt\b/,
+      /\b(?:const|let|var)\s+\w*promptAsync\w*\s*=\s*[\w.]+\.session\.promptAsync\b/,
+      /\b(?:const|let|var)\s+\w*prompt\w*\s*=\s*[\w.]+\.session\.prompt\b/,
+    ]
 
     // when
     for (const filePath of files) {
@@ -50,7 +58,7 @@ describe("production prompt injection routes", () => {
       }
 
       const contents = uncommentedLines(await readFile(filePath, "utf8")).join("\n")
-      if (/\bsession\.promptAsync\s*\(/.test(contents) || /\bsession\.prompt\s*\(/.test(contents)) {
+      if (rawPromptPatterns.some((pattern) => pattern.test(contents))) {
         offenders.push(relativeSourcePath(filePath))
       }
     }