refactor(agent): one home for the stream parse-error markers

The SDK's malformed-frame ValueError substrings were hand-copied into the
retry classifier and the error summary; a third SDK message would need
both remembered. The mid-tool retry branch no longer clears
partial_tool_names itself — _start_stream_attempt resets it for every
attempt. buffer_anthropic_tool_input's docstring states the trade: the
knob stays on the turn's kwargs and the changed tools block costs one
prompt-cache miss.

agent/anthropic_adapter.py

@@ -628,7 +628,9 @@ def buffer_anthropic_tool_input(api_kwargs: dict[str, Any], base_url: str | None
     """Retry knob for a malformed fine-grained tool-JSON stream (#107830): the beta streams tool
     args unvalidated, so a model that emits ``{"names": cronjob_manage}`` breaks the SDK parser
     and an identical retry breaks identically. ``eager_input_streaming: false`` per tool restores
-    Anthropic's buffered, validated args for THIS request only. Off the happy path on purpose:
+    Anthropic's buffered, validated args for the rest of this turn (the flag lives on the turn's
+    kwargs, so a later retry of the same turn keeps it; the changed ``tools`` block costs one
+    prompt-cache miss, cheaper than a dead turn). Off the happy path on purpose:
     buffering a large payload is a zero-event gap the stale-stream detector kills. No-op on
     endpoints that never get the beta (MiniMax) rather than sending them an unknown field."""
     if _TOOL_STREAMING_BETA not in _common_betas_for_base_url(base_url):

agent/api_error_summary.py

@@ -10,6 +10,11 @@ from typing import Any, Dict, Optional
 
 from agent.redact import redact_sensitive_text
 
+# Substrings of the plain ``ValueError`` the Anthropic SDK raises for a malformed event-stream
+# frame (wire trouble, not local validation). Read by ``AIAgent._is_provider_stream_parse_error``.
+PROVIDER_STREAM_PARSE_MARKERS = ("expected ident at line", "expected value at line")
+
+
 # Offline DNS failures are wrapped in a generic "Connection error" by SDKs — inspect the chain.
 _NETWORK_RESOLUTION_MARKERS = (
     "temporary failure in name resolution",
@@ -142,9 +147,7 @@ class ApiErrorSummaryMixin:
                 )
             current = current.__cause__ or current.__context__
 
-        if isinstance(error, ValueError) and any(
-            marker in raw.lower() for marker in ("expected ident at line", "expected value at line")
-        ):
+        if isinstance(error, ValueError) and any(marker in raw.lower() for marker in PROVIDER_STREAM_PARSE_MARKERS):
             return f"Malformed provider streaming response: {raw[:300]}"
 
         prefix = _http_prefix(error)

agent/chat_completion_helpers.py

@@ -3171,7 +3171,6 @@ class _StreamingCall(StreamingWaitMonitor):
             # reset the streamed-text buffer so it isn't double-recorded; fresh accumulators.
             self._quiet(self.agent._fire_stream_delta, "\n\n⚠ Connection dropped mid tool-call; reconnecting…\n\n")
             self._quiet(self.agent._reset_stream_delivery_tracking)
-            self.result["partial_tool_names"] = []
             self.deltas_were_sent["yes"] = False
             self.first_delta_fired["done"] = False
             self._retry_after_drop(e, attempt, max_retries, mid_tool_call=True, reason="stream_mid_tool_retry_cleanup")

run_agent.py

@@ -109,7 +109,7 @@ from agent.client_lifecycle import ClientLifecycleMixin
 from agent.stream_delivery import StreamDeliveryMixin
 from agent.status_output import StatusOutputMixin
 from agent.api_request_hooks import ApiRequestHooksMixin
-from agent.api_error_summary import ApiErrorSummaryMixin
+from agent.api_error_summary import PROVIDER_STREAM_PARSE_MARKERS, ApiErrorSummaryMixin
 from agent.interrupt_control import InterruptControlMixin
 from agent.turn_explainers import TurnExplainersMixin
 from agent.activity_tracking import ActivityTrackingMixin
@@ -485,8 +485,7 @@ class AIAgent(
         that is wire trouble, not local validation, so it follows the truncated-JSON retry path."""
         return (getattr(self, "api_mode", None) == "anthropic_messages" and isinstance(error, ValueError)
                 and not isinstance(error, (UnicodeEncodeError, json.JSONDecodeError))
-                and any(marker in str(error).strip().lower() for marker in (
-                    "expected ident at line", "expected value at line")))
+                and any(marker in str(error).strip().lower() for marker in PROVIDER_STREAM_PARSE_MARKERS))
 
     _log_stream_retry = _forward("agent.stream_diag", "log_stream_retry")
     _emit_stream_drop = _forward("agent.stream_diag", "emit_stream_drop")