From 881c2ddf53dfb97c66f7f7aa2e84f2bb58c645db Mon Sep 17 00:00:00 2001
From: Cameron <cameron@pfiffer.org>
Date: Wed, 4 Feb 2026 18:32:16 -0800
Subject: [PATCH] feat(hooks): Add additionalContext support for PostToolUse
 hooks (#826)

Co-authored-by: Letta <noreply@letta.com>
---
 src/hooks/executor.ts | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/hooks/executor.ts b/src/hooks/executor.ts
index b781bb3..4997169 100644
--- a/src/hooks/executor.ts
+++ b/src/hooks/executor.ts
@@ -358,6 +358,21 @@ export async function executeHooksParallel(
     const hook = hooks[i];
     if (!result || !hook) continue;
 
+    // For exit 0, try to parse JSON for additionalContext (matching Claude Code behavior)
+    if (result.exitCode === HookExitCode.ALLOW && result.stdout?.trim()) {
+      try {
+        const json = JSON.parse(result.stdout.trim());
+        const additionalContext =
+          json?.hookSpecificOutput?.additionalContext ||
+          json?.additionalContext;
+        if (additionalContext) {
+          feedback.push(additionalContext);
+        }
+      } catch {
+        // Not JSON, ignore
+      }
+    }
+
     // Format: [command]: {stderr} per spec
     if (result.exitCode === HookExitCode.BLOCK) {
       blocked = true;