How can I have LlamaParse automatically return Pydantic objects in Python?

Below is an approach to ensure that your LlamaParse output is converted directly into Pydantic objects without needing a separate API call.

Use a Structured Output Parser

LangChain provides output parsers that take the raw output and convert it into strictly structured data (such as Pydantic objects). Instead of relying solely on LlamaParse’s default behavior, you can use the PydanticOutputParser. For example, assuming you have defined a Pydantic model (e.g., Joke), you can configure your chain as follows:

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from langchain.output_parsers.pydantic import PydanticOutputParser
from your_models import Joke  # Your Pydantic model

# Create a parser that converts the LLM result into a Joke instance.
output_parser = PydanticOutputParser(pydantic_object=Joke)

# Now, set up your chain (this can be LlamaParseChain or an equivalent)
chain = LlamaParseChain(output_parser=output_parser)

# Invoke the chain
result = chain.invoke("Tell me a joke about cats")
print(result)

Consider the include_raw=True Parameter

If you need insight into both the raw and parsed output—for example, to diagnose parsing issues—LangChain allows you to include the raw output. This can be enabled by setting include_raw=True during the structured output configuration:

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structured_llm = llm.with_structured_output(Joke, include_raw=True)
result = structured_llm.invoke("Tell me a joke about cats")
print(result)

This returns a dictionary with keys like raw, parsed, and parsing_error, letting you inspect the raw output if needed while still getting your structured Pydantic object under parsed.

Summary

• Use PydanticOutputParser: Convert LLM outputs directly into Pydantic instances.
• Include raw output: Enable include_raw=True if you need both the raw and parsed data.
• Define your schema: Ensure your Pydantic model/schema (e.g., Joke) correctly represents the expected structure.

By using these strategies, you streamline your workflow by having the result returned in a strictly structured format without making an additional parsing API call.