From bb6a011964540cb6a328516f7306bc1526282373 Mon Sep 17 00:00:00 2001
From: bob_karrot <bob@daangn.com>
Date: Wed, 11 Feb 2026 14:23:37 +0900
Subject: [PATCH] fix(hooks): guard against non-string tool output in
 afterToolResult hooks

MCP tools can return non-string results (e.g. structured JSON objects).
When this happens, output.output is undefined, causing TypeError crashes
in edit-error-recovery and delegate-task-retry hooks that call methods
like .toLowerCase() without checking the type first.

Add typeof string guard in both hooks, consistent with the existing
pattern used in tool-output-truncator.
---
 src/hooks/delegate-task-retry/hook.ts | 1 +
 src/hooks/edit-error-recovery/hook.ts | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/hooks/delegate-task-retry/hook.ts b/src/hooks/delegate-task-retry/hook.ts
index 915da323d..97e27b3f4 100644
--- a/src/hooks/delegate-task-retry/hook.ts
+++ b/src/hooks/delegate-task-retry/hook.ts
@@ -10,6 +10,7 @@ export function createDelegateTaskRetryHook(_ctx: PluginInput) {
       output: { title: string; output: string; metadata: unknown }
     ) => {
       if (input.tool.toLowerCase() !== "task") return
+      if (typeof output.output !== "string") return
 
       const errorInfo = detectDelegateTaskError(output.output)
       if (errorInfo) {
diff --git a/src/hooks/edit-error-recovery/hook.ts b/src/hooks/edit-error-recovery/hook.ts
index 84ac9e9dc..d71540bee 100644
--- a/src/hooks/edit-error-recovery/hook.ts
+++ b/src/hooks/edit-error-recovery/hook.ts
@@ -43,6 +43,7 @@ export function createEditErrorRecoveryHook(_ctx: PluginInput) {
       output: { title: string; output: string; metadata: unknown }
     ) => {
       if (input.tool.toLowerCase() !== "edit") return
+      if (typeof output.output !== "string") return
 
       const outputLower = output.output.toLowerCase()
       const hasEditError = EDIT_ERROR_PATTERNS.some((pattern) =>