hermes-agent/agent/transports/anthropic.py
bobashopcashier b49a1b71a7 fix(agent): accept empty content with stop_reason=end_turn as valid anthropic response
Anthropic's API can legitimately return content=[] with stop_reason="end_turn"
when the model has nothing more to add after a turn that already delivered the
user-facing text alongside a trivial tool call (e.g. memory write). The transport
validator was treating that as an invalid response, triggering 3 retries that
each returned the same valid-but-empty response, then failing the run with
"Invalid API response after 3 retries."

The downstream normalizer already handles empty content correctly (empty loop
over response.content, content=None, finish_reason="stop"), so the only fix
needed is at the validator boundary.

Tests:
- Empty content + stop_reason="end_turn" → valid (the fix)
- Empty content + stop_reason="tool_use" → still invalid (regression guard)
- Empty content without stop_reason → still invalid (existing behavior preserved)
2026-04-22 14:26:23 -07:00

135 lines
4.9 KiB
Python

"""Anthropic Messages API transport.
Delegates to the existing adapter functions in agent/anthropic_adapter.py.
This transport owns format conversion and normalization — NOT client lifecycle.
"""
from typing import Any, Dict, List, Optional
from agent.transports.base import ProviderTransport
from agent.transports.types import NormalizedResponse
class AnthropicTransport(ProviderTransport):
"""Transport for api_mode='anthropic_messages'.
Wraps the existing functions in anthropic_adapter.py behind the
ProviderTransport ABC. Each method delegates — no logic is duplicated.
"""
@property
def api_mode(self) -> str:
return "anthropic_messages"
def convert_messages(self, messages: List[Dict[str, Any]], **kwargs) -> Any:
"""Convert OpenAI messages to Anthropic (system, messages) tuple.
kwargs:
base_url: Optional[str] — affects thinking signature handling.
"""
from agent.anthropic_adapter import convert_messages_to_anthropic
base_url = kwargs.get("base_url")
return convert_messages_to_anthropic(messages, base_url=base_url)
def convert_tools(self, tools: List[Dict[str, Any]]) -> Any:
"""Convert OpenAI tool schemas to Anthropic input_schema format."""
from agent.anthropic_adapter import convert_tools_to_anthropic
return convert_tools_to_anthropic(tools)
def build_kwargs(
self,
model: str,
messages: List[Dict[str, Any]],
tools: Optional[List[Dict[str, Any]]] = None,
**params,
) -> Dict[str, Any]:
"""Build Anthropic messages.create() kwargs.
Calls convert_messages and convert_tools internally.
params (all optional):
max_tokens: int
reasoning_config: dict | None
tool_choice: str | None
is_oauth: bool
preserve_dots: bool
context_length: int | None
base_url: str | None
fast_mode: bool
"""
from agent.anthropic_adapter import build_anthropic_kwargs
return build_anthropic_kwargs(
model=model,
messages=messages,
tools=tools,
max_tokens=params.get("max_tokens", 16384),
reasoning_config=params.get("reasoning_config"),
tool_choice=params.get("tool_choice"),
is_oauth=params.get("is_oauth", False),
preserve_dots=params.get("preserve_dots", False),
context_length=params.get("context_length"),
base_url=params.get("base_url"),
fast_mode=params.get("fast_mode", False),
)
def normalize_response(self, response: Any, **kwargs) -> NormalizedResponse:
"""Normalize Anthropic response to NormalizedResponse.
kwargs:
strip_tool_prefix: bool — strip 'mcp_mcp_' prefixes from tool names.
"""
from agent.anthropic_adapter import normalize_anthropic_response_v2
strip_tool_prefix = kwargs.get("strip_tool_prefix", False)
return normalize_anthropic_response_v2(response, strip_tool_prefix=strip_tool_prefix)
def validate_response(self, response: Any) -> bool:
"""Check Anthropic response structure is valid.
An empty content list is legitimate when ``stop_reason == "end_turn"``
— the model's canonical way of signalling "nothing more to add" after
a tool turn that already delivered the user-facing text. Treating it
as invalid falsely retries a completed response.
"""
if response is None:
return False
content_blocks = getattr(response, "content", None)
if not isinstance(content_blocks, list):
return False
if not content_blocks:
return getattr(response, "stop_reason", None) == "end_turn"
return True
def extract_cache_stats(self, response: Any) -> Optional[Dict[str, int]]:
"""Extract Anthropic cache_read and cache_creation token counts."""
usage = getattr(response, "usage", None)
if usage is None:
return None
cached = getattr(usage, "cache_read_input_tokens", 0) or 0
written = getattr(usage, "cache_creation_input_tokens", 0) or 0
if cached or written:
return {"cached_tokens": cached, "creation_tokens": written}
return None
# Promote the adapter's canonical mapping to module level so it's shared
_STOP_REASON_MAP = {
"end_turn": "stop",
"tool_use": "tool_calls",
"max_tokens": "length",
"stop_sequence": "stop",
"refusal": "content_filter",
"model_context_window_exceeded": "length",
}
def map_finish_reason(self, raw_reason: str) -> str:
"""Map Anthropic stop_reason to OpenAI finish_reason."""
return self._STOP_REASON_MAP.get(raw_reason, "stop")
# Auto-register on import
from agent.transports import register_transport # noqa: E402
register_transport("anthropic_messages", AnthropicTransport)