diff --git a/agent/display.py b/agent/display.py
index 97be479fe7..0627480457 100644
--- a/agent/display.py
+++ b/agent/display.py
@@ -210,18 +210,13 @@ def _scan_quoted(text: str) -> Iterator[tuple[int, str, bool]]:
 
 
 def _split_shell_words(segment: str) -> list[str]:
-    words: list[str] = []
-    buf: list[str] = []
+    parts: list[list[str]] = [[]]
     for _, ch, quoted in _scan_quoted(segment):
         if not quoted and ch.isspace():
-            if buf:
-                words.append("".join(buf))
-                buf = []
+            parts.append([])
         else:
-            buf.append(ch)
-    if buf:
-        words.append("".join(buf))
-    return words
+            parts[-1].append(ch)
+    return ["".join(p) for p in parts if p]
 
 
 def _strip_shell_pipe_tail(segment: str) -> str:
@@ -236,30 +231,20 @@ def _strip_shell_pipe_tail(segment: str) -> str:
 
 def _split_shell_compound(command: str) -> list[str]:
     """Split on unquoted ``&&`` / ``||`` / ``;`` / newline, dropping pipe tails per segment."""
-    segments: list[str] = []
-    buf: list[str] = []
+    raw: list[list[str]] = [[]]
     skip = False
-
-    def _flush() -> None:
-        segment = _strip_shell_pipe_tail("".join(buf).strip())
-        if segment:
-            segments.append(segment)
-        buf.clear()
-
     for i, ch, quoted in _scan_quoted(command):
         if skip:
             skip = False
-            continue
-        if not quoted and (command.startswith("&&", i) or command.startswith("||", i)):
-            _flush()
+        elif not quoted and (command.startswith("&&", i) or command.startswith("||", i)):
+            raw.append([])
             skip = True
-            continue
-        if not quoted and ch in {";", "\n"}:
-            _flush()
-            continue
-        buf.append(ch)
-    _flush()
-    return segments
+        elif not quoted and ch in {";", "\n"}:
+            raw.append([])
+        else:
+            raw[-1].append(ch)
+    segments = (_strip_shell_pipe_tail("".join(buf).strip()) for buf in raw)
+    return [s for s in segments if s]
 
 
 def _shell_head_word(segment: str) -> str:
@@ -278,13 +263,12 @@ def _clean_shell_segment(segment: str) -> str:
     while i < len(words):
         word = words[i]
         if re.match(r"^\d*(?:>>?|<)$", word):
-            i += 2
-            continue
-        if re.match(r"^\d*(?:>&|<&)\d+$", word) or re.match(r"^\d*>&\d+$", word):
+            i += 2  # operator + target
+        elif re.match(r"^\d*(?:>&|<&)\d+$", word):
+            i += 1
+        else:
+            out.append(word)
             i += 1
-            continue
-        out.append(word)
-        i += 1
     return " ".join(out).strip()
 
 
diff --git a/agent/error_classifier.py b/agent/error_classifier.py
index abea68b4e3..45c310f6b8 100644
--- a/agent/error_classifier.py
+++ b/agent/error_classifier.py
@@ -323,26 +323,23 @@ def _v(reason: FailoverReason, **hints: Any) -> Verdict:
 
 
 _ROTATE_FALLBACK = {"should_rotate_credential": True, "should_fallback": True}
+_ABORT_FALLBACK = {"retryable": False, "should_fallback": True}
+_R = FailoverReason
 
-_V_BILLING = _v(FailoverReason.billing, retryable=False, **_ROTATE_FALLBACK)
-_V_RATE_LIMIT = _v(FailoverReason.rate_limit, **_ROTATE_FALLBACK)
-_V_OVERLOADED = _v(FailoverReason.overloaded)
-_V_SERVER_ERROR = _v(FailoverReason.server_error)
-_V_CONTEXT_OVERFLOW = _v(FailoverReason.context_overflow, should_compress=True)
-_V_PAYLOAD_TOO_LARGE = _v(FailoverReason.payload_too_large, should_compress=True)
-_V_MODEL_NOT_FOUND = _v(FailoverReason.model_not_found, retryable=False, should_fallback=True)
-_V_POLICY_BLOCKED = _v(FailoverReason.provider_policy_blocked, retryable=False)
-_V_CONTENT_BLOCKED = _v(FailoverReason.content_policy_blocked, retryable=False, should_fallback=True)
-_V_FORMAT_ERROR = _v(FailoverReason.format_error, retryable=False, should_fallback=True)
-_V_AUTH_ROTATE = _v(FailoverReason.auth, retryable=False, **_ROTATE_FALLBACK)
-_V_AUTH_FALLBACK = _v(FailoverReason.auth, retryable=False, should_fallback=True)
-_V_TIMEOUT = _v(FailoverReason.timeout)
-_V_SSL_CERT = _v(FailoverReason.ssl_cert_verification, retryable=False)
-_V_IMAGE_TOO_LARGE = _v(FailoverReason.image_too_large)
-_V_IMAGE_CORRUPT = _v(FailoverReason.image_corrupt)
-_V_MULTIMODAL = _v(FailoverReason.multimodal_tool_content_unsupported)
-_V_INVALID_ENCRYPTED = _v(FailoverReason.invalid_encrypted_content)
-_V_UNKNOWN = _v(FailoverReason.unknown)
+_V_BILLING = _v(_R.billing, retryable=False, **_ROTATE_FALLBACK)
+_V_RATE_LIMIT = _v(_R.rate_limit, **_ROTATE_FALLBACK)
+_V_AUTH_ROTATE = _v(_R.auth, retryable=False, **_ROTATE_FALLBACK)
+_V_AUTH_FALLBACK = _v(_R.auth, **_ABORT_FALLBACK)
+_V_MODEL_NOT_FOUND = _v(_R.model_not_found, **_ABORT_FALLBACK)
+_V_CONTENT_BLOCKED = _v(_R.content_policy_blocked, **_ABORT_FALLBACK)
+_V_FORMAT_ERROR = _v(_R.format_error, **_ABORT_FALLBACK)
+_V_POLICY_BLOCKED = _v(_R.provider_policy_blocked, retryable=False)
+_V_SSL_CERT = _v(_R.ssl_cert_verification, retryable=False)
+_V_CONTEXT_OVERFLOW = _v(_R.context_overflow, should_compress=True)
+_V_PAYLOAD_TOO_LARGE = _v(_R.payload_too_large, should_compress=True)
+_V_OVERLOADED, _V_SERVER_ERROR, _V_TIMEOUT, _V_UNKNOWN = map(_v, (_R.overloaded, _R.server_error, _R.timeout, _R.unknown))
+_V_IMAGE_TOO_LARGE, _V_IMAGE_CORRUPT = _v(_R.image_too_large), _v(_R.image_corrupt)
+_V_MULTIMODAL, _V_INVALID_ENCRYPTED = _v(_R.multimodal_tool_content_unsupported), _v(_R.invalid_encrypted_content)
 
 
 def _billing_hints(error_msg: str) -> Verdict: