From 786df99dc7c33c60b7f09355898542de9ea983ee Mon Sep 17 00:00:00 2001
From: Zaki Manian <zaki@manian.org>
Date: Mon, 16 Mar 2026 14:57:35 +0000
Subject: [PATCH] =?UTF-8?q?fix:=20address=20review=20feedback=20=E2=80=94?=
 =?UTF-8?q?=20UTF-8=20safe=20truncation,=20saturating=5Fsub,=20lock=20pois?=
 =?UTF-8?q?on=20logging,=20cleanup?=
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Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/tools/builtin/ptc_script.rs | 24 +++++++++++++++++++++++-
 src/tools/registry.rs           |  2 ++
 src/tools/wasm/wrapper.rs       |  2 +-
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/tools/builtin/ptc_script.rs b/src/tools/builtin/ptc_script.rs
index 205ef603..2e75a6cc 100644
--- a/src/tools/builtin/ptc_script.rs
+++ b/src/tools/builtin/ptc_script.rs
@@ -118,9 +118,13 @@ impl PtcScriptTool {
         if output.len() <= MAX_OUTPUT_SIZE {
             output.to_string()
         } else {
+            let mut i = MAX_OUTPUT_SIZE;
+            while i > 0 && !output.is_char_boundary(i) {
+                i -= 1;
+            }
             format!(
                 "{}\n\n[Output truncated at {} bytes]",
-                &output[..MAX_OUTPUT_SIZE],
+                &output[..i],
                 MAX_OUTPUT_SIZE
             )
         }
@@ -335,6 +339,24 @@ mod tests {
         assert!(truncated.contains("[Output truncated"));
     }
 
+    #[test]
+    fn test_truncate_output_multibyte_boundary() {
+        // Build a string of multi-byte chars (emoji = 4 bytes each) that crosses MAX_OUTPUT_SIZE
+        let emoji = "\u{1F600}"; // 4 bytes
+        let count = MAX_OUTPUT_SIZE / emoji.len() + 10;
+        let long: String = emoji.repeat(count);
+        assert!(long.len() > MAX_OUTPUT_SIZE);
+
+        let truncated = PtcScriptTool::truncate_output(&long);
+        // Must not panic and must contain valid UTF-8
+        assert!(truncated.contains("[Output truncated"));
+        // The kept portion must end on a char boundary (valid UTF-8 guaranteed by compilation)
+        let kept = truncated.split("\n\n[Output truncated").next().unwrap();
+        assert!(kept.len() <= MAX_OUTPUT_SIZE);
+        // Every char should be complete (no partial emoji)
+        assert!(kept.chars().all(|c| c == '\u{1F600}'));
+    }
+
     #[test]
     fn test_tool_metadata() {
         let tool = PtcScriptTool::new();
diff --git a/src/tools/registry.rs b/src/tools/registry.rs
index d5e92245..ca015325 100644
--- a/src/tools/registry.rs
+++ b/src/tools/registry.rs
@@ -157,6 +157,8 @@ impl ToolRegistry {
     pub fn set_tool_executor(&self, executor: Arc<ToolExecutor>) {
         if let Ok(mut guard) = self.tool_executor_slot.write() {
             *guard = Some(executor);
+        } else {
+            tracing::error!("tool_executor_slot RwLock is poisoned; PTC will be unavailable");
         }
     }
 
diff --git a/src/tools/wasm/wrapper.rs b/src/tools/wasm/wrapper.rs
index a1756d64..b98c6392 100644
--- a/src/tools/wasm/wrapper.rs
+++ b/src/tools/wasm/wrapper.rs
@@ -46,7 +46,7 @@ struct NestingGuard<'a> {
 
 impl Drop for NestingGuard<'_> {
     fn drop(&mut self) {
-        *self.depth -= 1;
+        *self.depth = self.depth.saturating_sub(1);
     }
 }