Files
TradingAgents/tradingagents/agents/utils/structured.py
Yijia-Xiao 517eeaf4b9 fix(structured): harden structured output for local servers and thinking models
- Local servers (LM Studio, vLLM) reject the object-form tool_choice langchain
  sends for function calling. The generic openai_compatible provider now binds
  the schema as a tool without forcing tool_choice.
- A structured call can return no parsed result (a thinking model answering in
  plain text); fall back to free text with a clear reason instead of an opaque
  render error.
2026-06-21 22:09:43 +00:00

80 lines
3.0 KiB
Python

"""Shared helpers for invoking an agent with structured output and a graceful fallback.
The Portfolio Manager, Trader, and Research Manager all follow the same
canonical pattern:
1. At agent creation, wrap the LLM with ``with_structured_output(Schema)``
so the model returns a typed Pydantic instance. If the provider does
not support structured output (rare; mostly older Ollama models), the
wrap is skipped and the agent uses free-text generation instead.
2. At invocation, run the structured call and render the result back to
markdown. If the structured call itself fails for any reason
(malformed JSON from a weak model, transient provider issue), fall
back to a plain ``llm.invoke`` so the pipeline never blocks.
Centralising the pattern here keeps the agent factories small and ensures
all three agents log the same warnings when fallback fires.
"""
from __future__ import annotations
import logging
from collections.abc import Callable
from typing import Any, TypeVar
from pydantic import BaseModel
logger = logging.getLogger(__name__)
T = TypeVar("T", bound=BaseModel)
def bind_structured(llm: Any, schema: type[T], agent_name: str) -> Any | None:
"""Return ``llm.with_structured_output(schema)`` or ``None`` if unsupported.
Logs a warning when the binding fails so the user understands the agent
will use free-text generation for every call instead of one-shot fallback.
"""
try:
return llm.with_structured_output(schema)
except (NotImplementedError, AttributeError) as exc:
logger.warning(
"%s: provider does not support with_structured_output (%s); "
"falling back to free-text generation",
agent_name, exc,
)
return None
def invoke_structured_or_freetext(
structured_llm: Any | None,
plain_llm: Any,
prompt: Any,
render: Callable[[T], str],
agent_name: str,
) -> str:
"""Run the structured call and render to markdown; fall back to free-text on any failure.
``prompt`` is whatever the underlying LLM accepts (a string for chat
invocations, a list of message dicts for chat models that take that
shape). The same value is forwarded to the free-text path so the
fallback sees the same input the structured call did.
"""
if structured_llm is not None:
try:
result = structured_llm.invoke(prompt)
if result is None:
# A thinking model can answer in plain text instead of calling
# the tool, leaving the parser with nothing to return. Treat it
# as a structured miss and fall back, with a clear reason.
raise ValueError("structured output returned no parsed result")
return render(result)
except Exception as exc:
logger.warning(
"%s: structured-output invocation failed (%s); retrying once as free text",
agent_name, exc,
)
response = plain_llm.invoke(prompt)
return response.content