Output Parsing Modules

LlamaIndex Framework

Component Guides

Querying

Structured Outputs

LlamaIndex supports integrations with output parsing modules offered by other frameworks. These output parsing modules can be used in the following ways:

To provide formatting instructions for any prompt / query (through output_parser.format)
To provide “parsing” for LLM outputs (through output_parser.parse)

Guardrails

Guardrails is an open-source Python package for specification/validation/correction of output schemas. See below for a code example.

from llama_index.core import VectorStoreIndex, SimpleDirectoryReader
from llama_index.output_parsers.guardrails import GuardrailsOutputParser
from llama_index.llms.openai import OpenAI


# load documents, build index
documents = SimpleDirectoryReader("../paul_graham_essay/data").load_data()
index = VectorStoreIndex(documents, chunk_size=512)

# define query / output spec
rail_spec = """
<rail version="0.1">

<output>
    <list name="points" description="Bullet points regarding events in the author's life.">
        <object>
            <string name="explanation" format="one-line" on-fail-one-line="noop" />
            <string name="explanation2" format="one-line" on-fail-one-line="noop" />
            <string name="explanation3" format="one-line" on-fail-one-line="noop" />
        </object>
    </list>
</output>

<prompt>

Query string here.

@xml_prefix_prompt

{output_schema}

@json_suffix_prompt_v2_wo_none
</prompt>
</rail>
"""

# define output parser
output_parser = GuardrailsOutputParser.from_rail_string(
    rail_spec, llm=OpenAI()
)

# Attach output parser to LLM
llm = OpenAI(output_parser=output_parser)

# obtain a structured response
query_engine = index.as_query_engine(llm=llm)
response = query_engine.query(
    "What are the three items the author did growing up?",
)
print(response)

Output:

{'points': [{'explanation': 'Writing short stories', 'explanation2': 'Programming on an IBM 1401', 'explanation3': 'Using microcomputers'}]}

Langchain

Langchain also offers output parsing modules that you can use within LlamaIndex.

from llama_index.core import VectorStoreIndex, SimpleDirectoryReader
from llama_index.core.output_parsers import LangchainOutputParser
from llama_index.llms.openai import OpenAI
from langchain.output_parsers import StructuredOutputParser, ResponseSchema


# load documents, build index
documents = SimpleDirectoryReader("../paul_graham_essay/data").load_data()
index = VectorStoreIndex.from_documents(documents)

# define output schema
response_schemas = [
    ResponseSchema(
        name="Education",
        description="Describes the author's educational experience/background.",
    ),
    ResponseSchema(
        name="Work",
        description="Describes the author's work experience/background.",
    ),
]

# define output parser
lc_output_parser = StructuredOutputParser.from_response_schemas(
    response_schemas
)
output_parser = LangchainOutputParser(lc_output_parser)

# Attach output parser to LLM
llm = OpenAI(output_parser=output_parser)

# obtain a structured response
query_engine = index.as_query_engine(llm=llm)
response = query_engine.query(
    "What are a few things the author did growing up?",
)
print(str(response))

Output:

{'Education': 'Before college, the author wrote short stories and experimented with programming on an IBM 1401.', 'Work': 'The author worked on writing and programming outside of school.'}

Guides

More examples: