diff --git a/agent/redact.py b/agent/redact.py
index 3679b732360c..df5d2b19e475 100644
--- a/agent/redact.py
+++ b/agent/redact.py
@@ -253,11 +253,18 @@ def _redact_form_body(text: str) -> str:
     return _redact_query_string(text.strip())
 
 
-def redact_sensitive_text(text: str) -> str:
+def redact_sensitive_text(text: str, code_file: bool = False) -> str:
     """Apply all redaction patterns to a block of text.
 
     Safe to call on any string -- non-matching text passes through unchanged.
     Disabled when security.redact_secrets is false in config.yaml.
+
+    Args:
+        text: The text to redact.
+        code_file: When True, skips ENV-assignment and JSON-field regex patterns
+            to avoid false positives on source code content (e.g. MAX_TOKENS=***
+            or "apiKey": "test" in test fixtures). Prefix patterns, auth headers,
+            private keys, DB connstrings, JWTs, and URL secrets are always redacted.
     """
     if text is None:
         return None
@@ -271,17 +278,18 @@ def redact_sensitive_text(text: str) -> str:
     # Known prefixes (sk-, ghp_, etc.)
     text = _PREFIX_RE.sub(lambda m: _mask_token(m.group(1)), text)
 
-    # ENV assignments: OPENAI_API_KEY=sk-abc...
-    def _redact_env(m):
-        name, quote, value = m.group(1), m.group(2), m.group(3)
-        return f"{name}={quote}{_mask_token(value)}{quote}"
-    text = _ENV_ASSIGN_RE.sub(_redact_env, text)
-
-    # JSON fields: "apiKey": "value"
-    def _redact_json(m):
-        key, value = m.group(1), m.group(2)
-        return f'{key}: "{_mask_token(value)}"'
-    text = _JSON_FIELD_RE.sub(_redact_json, text)
+    # ENV assignments: OPENAI_API_KEY=***  (skip for code files — false positives)
+    if not code_file:
+        def _redact_env(m):
+            name, quote, value = m.group(1), m.group(2), m.group(3)
+            return f"{name}={quote}{_mask_token(value)}{quote}"
+        text = _ENV_ASSIGN_RE.sub(_redact_env, text)
+
+        # JSON fields: "apiKey": "***"  (skip for code files — false positives)
+        def _redact_json(m):
+            key, value = m.group(1), m.group(2)
+            return f'{key}: "{_mask_token(value)}"'
+        text = _JSON_FIELD_RE.sub(_redact_json, text)
 
     # Authorization headers
     text = _AUTH_HEADER_RE.sub(
diff --git a/tools/file_tools.py b/tools/file_tools.py
index 609506c05e1b..182ba39e5164 100644
--- a/tools/file_tools.py
+++ b/tools/file_tools.py
@@ -479,7 +479,7 @@ def read_file_tool(path: str, offset: int = 1, limit: int = 500, task_id: str =
 
         # ── Redact secrets (after guard check to skip oversized content) ──
         if result.content:
-            result.content = redact_sensitive_text(result.content)
+            result.content = redact_sensitive_text(result.content, code_file=True)
             result_dict["content"] = result.content
 
         # Large-file hint: if the file is big and the caller didn't ask
@@ -846,7 +846,7 @@ def search_tool(pattern: str, target: str = "content", path: str = ".",
         if hasattr(result, 'matches'):
             for m in result.matches:
                 if hasattr(m, 'content') and m.content:
-                    m.content = redact_sensitive_text(m.content)
+                    m.content = redact_sensitive_text(m.content, code_file=True)
         result_dict = result.to_dict()
 
         if count >= 3: