Run a rapid evaluation

You can use the Vertex AI SDK for Python to programmatically evaluate your generative language models.

Install the Vertex AI SDK

To install rapid evaluation from the Vertex AI SDK for Python, run the following command:

pip install --upgrade google-cloud-aiplatform[rapid_evaluation]

For more information, see Install the Vertex AI SDK for Python.

Authenticate the Vertex AI SDK

After you install the Vertex AI SDK for Python, you need to authenticate. The following topics explain how to authenticate with the Vertex AI SDK if you're working locally and if you're working in Colaboratory:

  • If you're developing locally, set up Application Default Credentials (ADC) in your local environment:

    1. Install the Google Cloud CLI, then initialize it by running the following command:

      gcloud init
    2. Create local authentication credentials for your Google Account:

      gcloud auth application-default login

      A login screen is displayed. After you sign in, your credentials are stored in the local credential file used by ADC. For more information about working with ADC in a local environment, see Local development environment.

  • If you're working in Colaboratory, run the following command in a Colab cell to authenticate:

    from google.colab import auth

    This command opens a window where you can complete the authentication.

See the Rapid evaluation SDK reference to learn more about the rapid evaluation SDK.

Create an evaluation task

Because evaluation is mostly task-driven with the generative AI models, online evaluation introduces the evaluation task abstraction to facilitate evaluation use cases. To get fair comparisons for generative models, you might typically run evaluations for models and prompt templates against an evaluation dataset and its associated metrics repeatedly. The EvalTask class is designed to support this new evaluation paradigm. Additionally, the EvalTask lets you seamlessly integrate with Vertex AI Experiments, which can help track settings and results for each evaluation run. Vertex AI Experiments can help manage and interpret evaluation results, enabling you to take action in less time. The following sample shows how to create an instance of the EvalTask class and run an evaluation:

from vertexai.preview.evaluation import EvalTask

eval_task = EvalTask(
  metrics=["bleu", "rouge_l_sum"],

The metrics parameter accepts a list of metrics, allowing for the simultaneous evaluation of several metrics in a single evaluation call.

Evaluation dataset preparation

Datasets are passed to an EvalTask instance as a pandas DataFrame, where each row represents a separate evaluation example (called an instance), and each column represents a metric input parameter. See metrics for the inputs expected by each metric. We provide several examples for building the evaluation dataset for different evaluation tasks.

Summarization evaluation

Construct a dataset for pointwise summarization with the following metrics:

  • summarization_quality
  • groundedness
  • fulfillment
  • summarization_helpfulness
  • summarization_verbosity

Considering the required metric input parameters, you must include the following columns in our evaluation dataset:

  • instruction
  • context
  • response

In this example, we have two summarization instances. Construct the instruction and context fields as inputs, which are required by summarization task evaluations:

instructions = [
  # example 1
  "Summarize the text in one sentence.",
  # example 2
  "Summarize the text such that a five-year-old can understand.",

contexts = [
  # example 1
  """As part of a comprehensive initiative to tackle urban congestion and foster
sustainable urban living, a major city has revealed ambitious plans for an
extensive overhaul of its public transportation system. The project aims not
only to improve the efficiency and reliability of public transit but also to
reduce the city\'s carbon footprint and promote eco-friendly commuting options.
City officials anticipate that this strategic investment will enhance
accessibility for residents and visitors alike, ushering in a new era of
efficient, environmentally conscious urban transportation.""",
# example 2
  """A team of archaeologists has unearthed ancient artifacts shedding light on a
previously unknown civilization. The findings challenge existing historical
narratives and provide valuable insights into human history.""",

If you have your LLM response (the summarization) ready and want to do bring-your-own-prediction (BYOP) evaluation, you can construct your response input as follows:

responses = [
  # example 1
  "A major city is revamping its public transportation system to fight congestion, reduce emissions, and make getting around greener and easier.",
  # example 2
  "Some people who dig for old things found some very special tools and objects that tell us about people who lived a long, long time ago! What they found is like a new puzzle piece that helps us understand how people used to live.",

With these inputs, we are ready to construct our evaluation dataset and EvalTask.

eval_dataset = pd.DataFrame(
    "instruction": instructions,
    "context":  contexts,
    "response":  responses,

eval_task = EvalTask(

General text generation evaluation

Some model-based metrics such as coherence, fluency, and safety, only need the model response to assess quality:

eval_dataset = pd.DataFrame({
  "response": ["""The old lighthouse, perched precariously on the windswept cliff,
had borne witness to countless storms. Its once-bright beam, now dimmed by time
and the relentless sea spray, still flickered with stubborn defiance."""]

  eval_task = EvalTask(
  metrics=["coherence", "fluency", "safety"],

Computation-Based evaluation

Computation-based metrics, like exact match, bleu and rouge, compare a response to a reference and accordingly need both response and reference fields in the evaluation dataset:

eval_dataset = pd.DataFrame({
  "response": ["The Roman Senate was filled with exuberance due to Pompey's defeat in Asia."],
  "reference": ["The Roman Senate was filled with exuberance due to successes against Catiline."],

eval_task = EvalTask(
  metrics=["exact_match", "bleu", "rouge"],

Tool-Use evaluation

For tool-use evaluation, you only need to include the response and reference in the evaluation dataset.

eval_dataset = pd.DataFrame({
  "response": ["""{
    "content": "",
      "arguments": {"movie":"Mission Impossible", "time": "today 7:30PM"}
  "reference": ["""{
    "content": "",
      "arguments":{"movie":"Mission Impossible", "time": "today 7:30PM"}

eval_task = EvalTask(
  metrics=["tool_call_valid", "tool_name_match", "tool_parameter_key_match",

Metric bundles

Metric bundles combine commonly associated metrics to help simplify the evaluation process. The metrics are categorized into these four bundles:

  • Evaluation tasks: summarization, question answering, and text generation
  • Evaluation perspectives: similarity, safety, and quality
  • Input consistency: all metrics in the same bundle take the same dataset inputs
  • Evaluation paradigm: pointwise versus pairwise

You can use these metric bundles in the online evaluation service to help you optimize your customized evaluation workflow.

This table lists details about the available metric bundles:

Metrics bundle name Metric name User input
text_generation_similarity exact_match
tool_call_quality tool_call_valid
text_generation_quality coherence
text_generation_instruction_following fulfillment prediction
text_generation_safety safety prediction
text_generation_factuality groundedness prediction
summarization_pointwise_reference_free summarization_quality
summary_pairwise_reference_free pairwise_summarization_quality prediction
qa_pointwise_reference_free question_answering_quality
qa_pointwise_reference_based question_answering_correctness prediction
qa_pairwise_reference_free pairwise_question_answering_quality prediction

View evaluation results

After you define your evaluation task, run the task to get evaluation results, as follows:

eval_result: EvalResult = eval_task.evaluate(

The EvalResult class represents the result of an evaluation run, which includes summary metrics and a metrics table with an evaluation dataset instance and corresponding per-instance metrics. Define the class as follows:

class EvalResult:
  """Evaluation result.

    summary_metrics: the summary evaluation metrics for an evaluation run.
    metrics_table: a table containing eval inputs, ground truth, and
      metrics per row.
  summary_metrics: Dict[str, float]
  metrics_table: Optional[pd.DataFrame] = None

With the use of helper functions, the evaluation results can be displayed in the Colab notebook.

Summary quality


You can plot summary metrics in a radar or bar chart for visualization and comparison between results from different evaluation runs. This visualization can be helpful for evaluating different models and different prompt templates.

Radar chart

Bar chart metrics

Rapid evaluation API

For information about the rapid evaluation API, see the rapid evaluation API.

Understanding service accounts

The service accounts are used by the online evaluation service to get predictions from the online prediction service for model-based evaluation metrics. This service account is automatically provisioned on the first request to the online evaluation service.

Name Description Email address Role
Vertex AI Rapid Eval Service Agent The service account used to get predictions for model based evaluation. roles/aiplatform.rapidevalServiceAgent

The permissions associated to the rapid evaluation service agent are:

Role Permissions
Vertex AI Rapid Eval Service Agent (roles/aiplatform.rapidevalServiceAgent) aiplatform.endpoints.predict

What's next