diff --git a/agent/display.py b/agent/display.py
index e9a19ff6192..6c5c970aeff 100644
--- a/agent/display.py
+++ b/agent/display.py
@@ -14,6 +14,7 @@ from difflib import unified_diff
 from pathlib import Path
 
 from utils import safe_json_loads
+from agent.tool_result_classification import file_mutation_result_landed
 
 # ANSI escape codes for coloring tool failure indicators
 _RED = "\033[31m"
@@ -810,6 +811,8 @@ def _detect_tool_failure(tool_name: str, result: str | None) -> tuple[bool, str]
     """
     if result is None:
         return False, ""
+    if file_mutation_result_landed(tool_name, result):
+        return False, ""
 
     if tool_name == "terminal":
         data = safe_json_loads(result)
diff --git a/agent/tool_guardrails.py b/agent/tool_guardrails.py
index 3c85d782090..5a9ddd507ba 100644
--- a/agent/tool_guardrails.py
+++ b/agent/tool_guardrails.py
@@ -14,6 +14,7 @@ from dataclasses import dataclass, field
 from typing import Any, Mapping
 
 from utils import safe_json_loads
+from agent.tool_result_classification import file_mutation_result_landed
 
 
 IDEMPOTENT_TOOL_NAMES = frozenset(
@@ -196,6 +197,8 @@ def classify_tool_failure(tool_name: str, result: str | None) -> tuple[bool, str
     """
     if result is None:
         return False, ""
+    if file_mutation_result_landed(tool_name, result):
+        return False, ""
 
     if tool_name == "terminal":
         data = safe_json_loads(result)
diff --git a/agent/tool_result_classification.py b/agent/tool_result_classification.py
new file mode 100644
index 00000000000..e136e2964da
--- /dev/null
+++ b/agent/tool_result_classification.py
@@ -0,0 +1,26 @@
+"""Shared helpers for classifying tool result payloads."""
+
+from __future__ import annotations
+
+import json
+from typing import Any
+
+
+FILE_MUTATING_TOOL_NAMES = frozenset({"write_file", "patch"})
+
+
+def file_mutation_result_landed(tool_name: str, result: Any) -> bool:
+    """Return True when a file mutation result proves the write landed."""
+    if tool_name not in FILE_MUTATING_TOOL_NAMES or not isinstance(result, str):
+        return False
+    try:
+        data = json.loads(result.strip())
+    except Exception:
+        return False
+    if not isinstance(data, dict) or data.get("error"):
+        return False
+    if tool_name == "write_file":
+        return "bytes_written" in data
+    if tool_name == "patch":
+        return data.get("success") is True
+    return False
diff --git a/run_agent.py b/run_agent.py
index f0597c90880..a2185300931 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -181,6 +181,7 @@ from agent.tool_guardrails import (
     append_toolguard_guidance,
     toolguard_synthetic_result,
 )
+from agent.tool_result_classification import file_mutation_result_landed
 from agent.trajectory import (
     convert_scratchpad_to_think, has_incomplete_scratchpad,
     save_trajectory as _save_trajectory_to_file,
@@ -5347,7 +5348,8 @@ class AIAgent:
         targets = _extract_file_mutation_targets(tool_name, args)
         if not targets:
             return
-        if is_error:
+        landed = file_mutation_result_landed(tool_name, result)
+        if is_error and not landed:
             preview = _extract_error_preview(result)
             for path in targets:
                 # Keep the FIRST error we saw for a given path unless we
diff --git a/tests/agent/test_display.py b/tests/agent/test_display.py
index c6ad837af97..5e18fa17e0c 100644
--- a/tests/agent/test_display.py
+++ b/tests/agent/test_display.py
@@ -1,6 +1,7 @@
 """Tests for agent/display.py — build_tool_preview() and inline diff previews."""
 
 import os
+import json
 import pytest
 from unittest.mock import MagicMock, patch
 
@@ -149,6 +150,27 @@ class TestCuteToolMessagePreviewLength:
         assert path in line
         assert "..." not in line
 
+    def test_write_file_lint_error_result_is_not_marked_failed(self):
+        result = json.dumps({
+            "bytes_written": 12,
+            "lint": {"status": "error", "output": "SyntaxError: invalid syntax"},
+        })
+
+        line = get_cute_tool_message("write_file", {"path": "/tmp/a.py"}, 0.1, result=result)
+
+        assert "[error]" not in line
+
+    def test_patch_lsp_diagnostics_result_is_not_marked_failed(self):
+        result = json.dumps({
+            "success": True,
+            "diff": "--- a/tmp.py\n+++ b/tmp.py\n",
+            "lsp_diagnostics": "<diagnostics>ERROR [1:1] type mismatch</diagnostics>",
+        })
+
+        line = get_cute_tool_message("patch", {"path": "/tmp/a.py"}, 0.1, result=result)
+
+        assert "[error]" not in line
+
 
 class TestEditDiffPreview:
     def test_extract_edit_diff_for_patch(self):
diff --git a/tests/agent/test_tool_guardrails.py b/tests/agent/test_tool_guardrails.py
index c50be56f43e..26593b7ef62 100644
--- a/tests/agent/test_tool_guardrails.py
+++ b/tests/agent/test_tool_guardrails.py
@@ -7,6 +7,7 @@ from agent.tool_guardrails import (
     ToolCallGuardrailController,
     ToolCallSignature,
     canonical_tool_args,
+    classify_tool_failure,
 )
 
 
@@ -131,6 +132,21 @@ def test_success_resets_exact_signature_failure_streak():
     assert controller.before_call("web_search", args).action == "allow"
 
 
+def test_file_mutation_lint_error_result_is_not_a_tool_failure():
+    write_result = json.dumps({
+        "bytes_written": 12,
+        "lint": {"status": "error", "output": "SyntaxError: invalid syntax"},
+    })
+    patch_result = json.dumps({
+        "success": True,
+        "diff": "--- a/tmp.py\n+++ b/tmp.py\n",
+        "lsp_diagnostics": "<diagnostics>ERROR [1:1] type mismatch</diagnostics>",
+    })
+
+    assert classify_tool_failure("write_file", write_result) == (False, "")
+    assert classify_tool_failure("patch", patch_result) == (False, "")
+
+
 def test_same_tool_varying_args_warns_by_default_without_halting():
     controller = ToolCallGuardrailController(
         ToolCallGuardrailConfig(same_tool_failure_warn_after=2, same_tool_failure_halt_after=3)
diff --git a/tests/agent/test_tool_result_classification.py b/tests/agent/test_tool_result_classification.py
new file mode 100644
index 00000000000..2b4b5b150cf
--- /dev/null
+++ b/tests/agent/test_tool_result_classification.py
@@ -0,0 +1,30 @@
+"""Tests for shared tool result classification helpers."""
+
+import json
+
+from agent.tool_result_classification import file_mutation_result_landed
+
+
+def test_write_file_with_nested_lint_error_counts_as_landed():
+    result = json.dumps({
+        "bytes_written": 12,
+        "lint": {"status": "error", "output": "SyntaxError: invalid syntax"},
+    })
+
+    assert file_mutation_result_landed("write_file", result) is True
+
+
+def test_patch_with_nested_lsp_diagnostics_counts_as_landed():
+    result = json.dumps({
+        "success": True,
+        "diff": "--- a/tmp.py\n+++ b/tmp.py\n",
+        "lsp_diagnostics": "<diagnostics>ERROR [1:1] type mismatch</diagnostics>",
+    })
+
+    assert file_mutation_result_landed("patch", result) is True
+
+
+def test_top_level_file_mutation_error_does_not_count_as_landed():
+    result = json.dumps({"success": True, "error": "post-write verification failed"})
+
+    assert file_mutation_result_landed("patch", result) is False
diff --git a/tests/run_agent/test_file_mutation_verifier.py b/tests/run_agent/test_file_mutation_verifier.py
index fca002d2314..73684ad1c2e 100644
--- a/tests/run_agent/test_file_mutation_verifier.py
+++ b/tests/run_agent/test_file_mutation_verifier.py
@@ -166,6 +166,56 @@ class TestRecordFileMutationResult:
         )
         assert agent._turn_failed_file_mutations == {}
 
+    def test_write_file_with_lint_error_counts_as_landed(self):
+        agent = _bare_agent()
+        agent._record_file_mutation_result(
+            "write_file",
+            {"path": "/tmp/a.py", "content": "bad"},
+            json.dumps({"error": "write failed"}),
+            is_error=True,
+        )
+        assert "/tmp/a.py" in agent._turn_failed_file_mutations
+
+        result = json.dumps({
+            "bytes_written": 24,
+            "lint": {"status": "error", "output": "SyntaxError: invalid syntax"},
+        })
+
+        agent._record_file_mutation_result(
+            "write_file",
+            {"path": "/tmp/a.py", "content": "def nope(:\n"},
+            result,
+            is_error=True,
+        )
+
+        assert agent._turn_failed_file_mutations == {}
+
+    def test_patch_with_lsp_diagnostics_counts_as_landed(self):
+        agent = _bare_agent()
+        agent._record_file_mutation_result(
+            "patch",
+            {"mode": "replace", "path": "/tmp/a.py", "old_string": "x", "new_string": "y"},
+            json.dumps({"error": "Could not find old_string"}),
+            is_error=True,
+        )
+        assert "/tmp/a.py" in agent._turn_failed_file_mutations
+
+        result = json.dumps({
+            "success": True,
+            "diff": "--- a/tmp.py\n+++ b/tmp.py\n",
+            "files_modified": ["/tmp/a.py"],
+            "lsp_diagnostics": "<diagnostics>ERROR [1:1] type mismatch</diagnostics>",
+        })
+
+        agent._record_file_mutation_result(
+            "patch",
+            {"mode": "replace", "path": "/tmp/a.py", "old_string": "x", "new_string": "y"},
+            result,
+            is_error=True,
+        )
+
+        assert agent._turn_failed_file_mutations == {}
+
     def test_repeated_failure_keeps_first_error(self):
         agent = _bare_agent()
         agent._record_file_mutation_result(