From 50efbe56148f754489df23b9fa111dafdbe6155d Mon Sep 17 00:00:00 2001
From: gnanam1990 <gnanasekaran.sekareee@gmail.com>
Date: Mon, 6 Apr 2026 18:08:01 +0530
Subject: [PATCH] fix: skip streaming normalization on finish_reason length

Truncated tool calls (finish_reason: 'length') now preserve the raw
buffer instead of normalizing into executable commands, preventing
incomplete commands from becoming runnable.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 src/services/api/openaiShim.test.ts |  2 +-
 src/services/api/openaiShim.ts      | 20 +++++++++++++-------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/services/api/openaiShim.test.ts b/src/services/api/openaiShim.test.ts
index e84ff27c..b47d84f6 100644
--- a/src/services/api/openaiShim.test.ts
+++ b/src/services/api/openaiShim.test.ts
@@ -1420,7 +1420,7 @@ test('does not normalize incomplete streamed Bash commands when finish_reason is
     .map(event => (event.delta as Record<string, unknown>).partial_json)
     .join('')
 
-  expect(streamedInput).toBe('{"command":"rg --fi"}')
+  expect(streamedInput).toBe('rg --fi')
 })
 
 test('does not repair truncated Bash objects that do not contain command', async () => {
diff --git a/src/services/api/openaiShim.ts b/src/services/api/openaiShim.ts
index c781563c..f1100e0e 100644
--- a/src/services/api/openaiShim.ts
+++ b/src/services/api/openaiShim.ts
@@ -692,16 +692,22 @@ async function* openaiStreamToAnthropic(
           // Close active tool calls
           for (const [, tc] of activeToolCalls) {
             if (tc.normalizeAtStop) {
-              const repairedStructuredJson = repairPossiblyTruncatedObjectJson(
-                tc.jsonBuffer,
-              )
               let partialJson: string
-              if (repairedStructuredJson) {
-                partialJson = repairedStructuredJson
+              if (choice.finish_reason === 'length') {
+                // Truncated by max tokens — preserve raw buffer to avoid
+                // turning an incomplete tool call into an executable command
+                partialJson = tc.jsonBuffer
               } else {
-                partialJson = JSON.stringify(
-                  normalizeToolArguments(tc.name, tc.jsonBuffer),
+                const repairedStructuredJson = repairPossiblyTruncatedObjectJson(
+                  tc.jsonBuffer,
                 )
+                if (repairedStructuredJson) {
+                  partialJson = repairedStructuredJson
+                } else {
+                  partialJson = JSON.stringify(
+                    normalizeToolArguments(tc.name, tc.jsonBuffer),
+                  )
+                }
               }
 
               yield {