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Run an evaluation with large file inputs

In addition to supporting file attachments with traces, LangSmith supports arbitrary file attachments with your examples, which you can consume when you run experiments.

This is particularly useful when working with LLM applications that require multimodal inputs or outputs.

Using separate attachments outside of inputs/outputs

When dealing with large files, it's recommended to upload them as attachments rather than embedding them in your JSON inputs or outputs via base64 encoding.

Attachments are more efficient because base64 encoding increases data size, leading to slower uploads and downloads. This also avoid potential performance bottlenecks with parsing large JSON payloads.

Finally, attachments are more user-friendly in the LangSmith UI, as they are rendered as files with previews, rather than as base64-encoded strings.

Add examples with attachments to a LangSmith dataset​

SDK​

To upload examples with attachments using the SDK, you need to use the upload_examples_multipart/update_examples_multipart Python methods or the uploadExamplesMultipart/updateExamplesMultipart TypeScript methods. This method allows you to pass in a list of examples with attachments.

Minimum SDK Versions

All of the below features are available in the following SDK versions:

  • Python SDK: >=0.2.3
  • JS/TS SDK: >=0.2.13

In the Python SDK, you can use the upload_examples_multipart method to upload examples with attachments.

Note that this is a different method from the standard create_examples method, which currently not support attachments.

Utilize the ExampleUploadWithAttachments type to define examples with attachments.

Each Attachment requires:

  • mime_type (str): The MIME type of the file (e.g., "image/png").
  • data (bytes): The binary content of the file.

You can also define an attachment with a tuple tuple of the form (mime_type, data) for convenience.

import requests
import uuid

from langsmith import Client
from langsmith.schemas import ExampleUploadWithAttachments, Attachment

# Publicly available test files
pdf_url = "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf"
wav_url = "https://openaiassets.blob.core.windows.net/$web/API/docs/audio/alloy.wav"
png_url = "https://www.w3.org/Graphics/PNG/nurbcup2si.png"

# Fetch the files as bytes

pdf_bytes = requests.get(pdf_url).content
wav_bytes = requests.get(wav_url).content
png_bytes = requests.get(png_url).content

# Define the LANGCHAIN_API_KEY environment variable with your API key
langsmith_client = Client()

dataset_name = "attachment-test-dataset:" + str(uuid.uuid4())[0:8]

dataset = langsmith_client.create_dataset(
  dataset_name=dataset_name,
  description="Test dataset for evals with publicly available attachments",
)

# Create example id
example_id = uuid.uuid4()

# Define the example with attachments

example = ExampleUploadWithAttachments(
  id=example_id,
  inputs={
      "audio_question": "What is in this audio clip?",
      "image_question": "What is in this image?"
  },
  outputs={
      "audio_answer": "The sun rises in the east and sets in the west. This simple fact has been observed by humans for thousands of years.",
      "image_answer": "A mug with a blanket over it."
  },
  attachments={
      "my_pdf": ("application/pdf", pdf_bytes),
      "my_wav": ("audio/wav", wav_bytes),
      "my_img": Attachment(mime_type="image/png", data=png_bytes)
  },
)

# Upload the examples with attachments
langsmith_client.upload_examples_multipart(dataset_id=dataset.id, uploads=[example])

Once you upload examples with attachments, you can view them in the LangSmith UI. Each attachment will be rendered as a file with a preview, making it easy to inspect the contents.

From existing runs​

When adding runs to a LangSmith dataset, attachments can be selectively propagated from the source run to the destination example. To learn more, please see this guide.

From the LangSmith UI​

You can also upload examples with attachments directly from the LangSmith UI. You can do so by clicking the + Example button in the Examples tab of the dataset UI. You can then upload the attachments that you want by using the "Upload Files" button:

Running evaluations with attachments​

Once you have a dataset that contains examples with file attachments, you can run evaluations that process these attachments.

Define a target function with attachments​

Now that we have a dataset that includes examples with attachments, we can define a target function to run over these examples. The following example simply uses OpenAI's GPT-4o model to answer questions about an image and an audio clip.

The target function you are evaluating must have two positional arguments in order to consume the attachments associated with the example, the first must be called inputs and the second must be called attachments.

  • The inputs argument is a dictionary that contains the input data for the example, excluding the attachments.
  • The attachments argument is a dictionary that maps the attachment name to a dictionary containing a presigned url and a reader of the bytes content of the file. Either can be used to read the bytes of the file: Each value in the attachments dictionary is a dictionary with the following structure:
{
    "presigned_url": str,
    "reader": BinaryIO
}

from langsmith.wrappers import wrap_openai

import base64
from openai import OpenAI

client = wrap_openai(OpenAI())

# Define target function that uses attachments
def file_qa(inputs, attachments): # Read the audio bytes from the reader and encode them in base64
  audio_reader = attachments["my_wav"]["reader"]
  audio_b64 = base64.b64encode(audio_reader.read()).decode('utf-8')
  audio_completion = client.chat.completions.create(
  model="gpt-4o-audio-preview",
  messages=[
      {
          "role": "user",
          "content": [
              {
                  "type": "text",
                  "text": inputs["audio_question"]
              },
              {
                  "type": "input_audio",
                  "input_audio": {
                      "data": audio_b64,
                      "format": "wav"
                  }
              }
          ]
      }
  ]

  # Most models support taking in an image URL directly in addition to base64 encoded images
  # You can pipe the image pre-signed URL directly to the model
  image_url = attachments["my_img"]["presigned_url"]
  image_completion = client.chat.completions.create(
      model="gpt-4o-mini",
      messages=[
        {
          "role": "user",
          "content": [
            {"type": "text", "text": inputs["image_question"]},
            {
              "type": "image_url",
              "image_url": {
                "url": image_url,
              },
            },
          ],
        }
      ],
  )

  return {
      "audio_answer": audio_completion.choices[0].message.content,
      "image_answer": image_completion.choices[0].message.content,
  }

Define custom evaluators with attachments​

In addition to using attachments inside of your target function, you can also use them inside of your evaluators as follows. The exact same rules apply as above to determine whether the evaluator should receive attachments.

The evaluator below uses an LLM to judge if the reasoning and the answer are consistent. To learn more about how to define llm-based evaluators, please see this guide.

# Assumes you've installed pydantic
from pydantic import BaseModel

def valid_image_description(outputs: dict, attachments: dict) -> bool:
  """Use an LLM to judge if the image description and ime are consistent."""

  instructions = """
  Does the description of the following image make sense?
  Please carefully review the image and the description to determine if the description is valid."""

  class Response(BaseModel):
      description_is_valid: bool

  image_url = attachments["my_img"]["presigned_url"]
  response = client.beta.chat.completions.parse(
      model="gpt-4o",
      messages=[
          {
              "role": "system",
              "content": instructions
          },
          {
              "role": "user",
              "content": [
                  {"type": "image_url", "image_url": {"url": image_url}},
                  {"type": "text", "text": outputs["image_answer"]}
              ]
          }
      ],
      response_format=Response
  )

  return response.choices[0].message.parsed.description_is_valid

langsmith_client.evaluate(
  file_qa,
  data=dataset_name,
  evaluators=[valid_image_description],
)

Manage datasets with attachments​

Manage programmatically​

In the code above, we showed how to add examples with attachments to a dataset. It is also possible to update these same examples using the SDK.

As with existing examples, datasets are versioned when you update them with attachments. Therefore, you can navigate to the dataset version history to see the changes made to each example. To learn more, please see this guide.

When updating an example with attachments, you can update attachments in a few different ways:

  • Pass in new attachments
  • Rename existing attachments
  • Delete existing attachments
from langsmith.schemas import ExampleUpdateWithAttachments, AttachmentsOperations
  
example_update = ExampleUpdateWithAttachments(
  id=example_id,
  attachments={
      # These are net new attachments
      "my_new_file": ("text/plain", b"foo bar"),
  },
  attachments_operations=AttachmentsOperations(
      # Retained attachments will stay exactly the same
      retain=["my_img"],
      # Renaming attachments preserves the original data
      rename={
          "my_wav": "my_new_wav",
      }
      # Any attachments not in rename/retain will be deleted
      # In this case, that would be "my_pdf"
  ),
)

langsmith_client.update_example_with_attachments(dataset_id=dataset.id, updates=[example_update])
Attachment Operations

Currently, errors are not thrown if you pass the wrong attaachment name to rename or retain. New attachments ALWAYS take precedence over existing attachments. So if you upload a new attachment name "foo" and try to retain or rename an existing attachment to "foo", the new attachment will be used instead.

Anything not in rename or retain will be deleted.

From the LangSmith UI​

Attachment Size Limit

Attachments are limited to 20MB in size in the UI.

When editing an example in the UI, you can upload new attachments, rename and delete attachemnts, and there is also a quick reset button to restore the attachments to what previously existed on the example. No changes will be saved until you click submit.

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