diff --git a/api/command_utils.py b/api/command_utils.py
index 7676b637..951c1630 100644
--- a/api/command_utils.py
+++ b/api/command_utils.py
@@ -1,13 +1,21 @@
 """Command parsing utilities for API optimizations."""
 
+import re
 import shlex
 
+_ENV_ASSIGNMENT_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*=.*$")
+
+
+def _is_env_assignment(part: str) -> bool:
+    """Return True when a token is a shell-style env assignment."""
+    return bool(_ENV_ASSIGNMENT_RE.match(part))
+
 
 def _strip_env_assignments(parts: list[str]) -> list[str]:
     """Return command parts after leading shell-style env assignments."""
     cmd_start = 0
     for i, part in enumerate(parts):
-        if "=" in part and not part.startswith("-"):
+        if _is_env_assignment(part):
             cmd_start = i + 1
         else:
             break
@@ -36,7 +44,7 @@ def extract_command_prefix(command: str) -> str:
         env_prefix = []
         cmd_start = 0
         for i, part in enumerate(parts):
-            if "=" in part and not part.startswith("-"):
+            if _is_env_assignment(part):
                 env_prefix.append(part)
                 cmd_start = i + 1
             else:
@@ -69,7 +77,11 @@ def extract_command_prefix(command: str) -> str:
         return first_word if not env_prefix else " ".join(env_prefix) + " " + first_word
 
     except ValueError:
-        return command.split()[0] if command.split() else "none"
+        parts = command.split()
+        if not parts:
+            return "none"
+        cmd_parts = _strip_env_assignments(parts)
+        return cmd_parts[0] if cmd_parts else "none"
 
 
 def extract_filepaths_from_command(command: str, output: str) -> str:
@@ -125,21 +137,19 @@ def extract_filepaths_from_command(command: str, output: str) -> str:
         if base_cmd == "grep":
             flags_with_args = {"-e", "-f", "-m", "-A", "-B", "-C"}
             pattern_provided_via_flag = False
-            positional: list[str] = []
+            positional = []
 
             skip_next = False
             for part in cmd_parts[1:]:
                 if skip_next:
                     skip_next = False
                     continue
-
                 if part.startswith("-"):
                     if part in flags_with_args:
                         if part in {"-e", "-f"}:
                             pattern_provided_via_flag = True
                         skip_next = True
                     continue
-
                 positional.append(part)
 
             filepaths = positional if pattern_provided_via_flag else positional[1:]