Developing agents

The Flyte agent framework enables rapid agent development, since agents are decoupled from the core FlytePropeller engine. Rather than building a complete gRPC service from scratch, you can implement an agent as a Python class, easing development. Agents can be tested independently and deployed privately, making maintenance easier and giving you more flexibility and control over development.

If you need to create a new type of task, we recommend creating a new agent to run it rather than running the task in a pod. After testing the new agent, you can update your FlytePropeller configMap to specify the type of task that the agent should run.


We strongly encourage you to contribute your agent to the Flyte community. To do so, follow the steps in “Contributing to Flyte” to add your agent to Flytekit and create an example of your agent for the Integrations documentation. If you have any questions, reach out to us on Slack.

There are two types of agents: async and sync.

  • Async agents enable long-running jobs that execute on an external platform over time. They communicate with external services that have asynchronous APIs that support create, get, and delete operations. The vast majority of agents are async agents.

  • Sync agents enable request/response services that return immediate outputs (e.g. calling an internal API to fetch data or communicating with the OpenAI API).


While agents can be written in any programming language, we currently only support Python agents. We may support other languages in the future.


1. Implement required methods

Async agent interface specification

To create a new async agent, extend the AsyncAgentBase class and implement create, get, and delete methods. These methods must be idempotent.

  • create: This method is used to initiate a new job. Users have the flexibility to use gRPC, REST, or an SDK to create a job.

  • get: This method retrieves the job resource (jobID or output literal) associated with the task, such as a BigQuery job ID or Databricks task ID.

  • delete: Invoking this method will send a request to delete the corresponding job.

from typing import Optional
from dataclasses import dataclass
from flytekit.models.literals import LiteralMap
from flytekit.models.task import TaskTemplate
from flytekit.extend.backend.base_agent import AsyncAgentBase, AgentRegistry, Resource, ResourceMeta

class BigQueryMetadata(ResourceMeta):
    This is the metadata for the job. For example, the id of the job.
    job_id: str

class BigQueryAgent(AsyncAgentBase):
    def __init__(self):
        super().__init__(task_type_name="bigquery", metadata_type=BigQueryMetadata)

    def create(
        task_template: TaskTemplate,
        inputs: Optional[LiteralMap] = None,
    ) -> BigQueryMetadata:
        job_id = submit_bigquery_job(inputs)
        return BigQueryMetadata(job_id=job_id)

    def get(self, resource_meta: BigQueryMetadata, **kwargs) -> Resource:
        phase, outputs = get_job_status(resource_meta.job_id)
        return Resource(phase=phase, outputs=outputs)

    def delete(self, resource_meta: BigQueryMetadata, **kwargs):

# To register the bigquery agent

For an example implementation, see the BigQuery agent.

Sync agent interface specification

To create a new sync agent, extend the SyncAgentBase class and implement a do method. This method must be idempotent.

  • do: This method is used to execute the synchronous task, and the worker in Flyte will be blocked until the method returns.

from typing import Optional
from flytekit import FlyteContextManager
from flytekit.core.type_engine import TypeEngine
from flyteidl.core.execution_pb2 import TaskExecution
from flytekit.models.literals import LiteralMap
from flytekit.models.task import TaskTemplate
from flytekit.extend.backend.base_agent import SyncAgentBase, AgentRegistry, Resource

class OpenAIAgent(SyncAgentBase):
    def __init__(self):

    def do(self, task_template: TaskTemplate, inputs: Optional[LiteralMap], **kwargs) -> Resource:
        # Convert the literal map to python value.
        ctx = FlyteContextManager.current_context()
        python_inputs = TypeEngine.literal_map_to_kwargs(ctx, inputs, literal_types=task_template.interface.inputs)
        response = ask_chatgpt_question(python_inputs)
        return Resource(phase=TaskExecution.SUCCEEDED, outputs={"o0": response})


Sensor interface specification

With the agent framework, you can easily build a custom sensor in Flyte to watch certain events or monitor the bucket in your workflow.

To create a new sensor, extend the [BaseSensor]( class and implement the poke method, which checks whether a specific condition is met.

from flytekit.sensor.base_sensor import BaseSensor
import s3fs

class FileSensor(BaseSensor):
    def __init__(self):

    def poke(self, path: str) -> bool:
        fs = s3fs.S3FileSystem()
        return fs.exists(path)

2. Test the agent

You can test your agent in a local Python environment or in a {ref}<local development cluster testing_agents_in_a_local_development_cluster>.

3. Build a new Docker image

The following is a sample Dockerfile for building an image for a Flyte agent:

FROM python:3.9-slim-buster

MAINTAINER Flyte Team <>
LABEL org.opencontainers.image.source=


# flytekit will autoload the agent if package is installed.
RUN pip install flytekitplugins-bigquery
CMD pyflyte serve agent --port 8000


For flytekit versions <=v1.10.2, use pyflyte serve. For flytekit versions >v1.10.2, use pyflyte serve agent.

4. Deploy Your Flyte agent

  1. Update the FlyteAgent deployment’s image

kubectl set image deployment/flyteagent
  1. Update the FlytePropeller configmap:

       - agent-service
       - bigquery_query_job_task: agent-service
       - custom_task: agent-service
  1. Restart FlytePropeller:

kubectl rollout restart deployment flytepropeller -n flyte

5. Canary deployment

Agents can be deployed independently in separate environments. Decoupling agents from the production environment ensures that if any specific agent encounters an error or issue, it will not impact the overall production system.

By running agents independently, you can thoroughly test and validate your agents in a controlled environment before deploying them to the production cluster.

By default, all agent requests will be sent to the default agent service. However, you can route particular task requests to designated agent services by adjusting the FlytePropeller configuration.

       - bigquery_query_job_task
       - default_task
       - custom_task
     # By default, all requests will be sent to the default agent.
       endpoint: "dns:///flyteagent.flyte.svc.cluster.local:8000"
       insecure: true
         # CreateTask, GetTask and DeleteTask are for async agents.
         # ExecuteTaskSync is for sync agents.
         CreateTask: 5s
         GetTask: 5s
         DeleteTask: 5s
         ExecuteTaskSync: 10s
       defaultTimeout: 10s
         endpoint: "dns:///custom-flyteagent.flyte.svc.cluster.local:8000"
         insecure: false
         defaultServiceConfig: '{"loadBalancingConfig": [{"round_robin":{}}]}'
           GetTask: 5s
         defaultTimeout: 10s
       # It will override the default agent for custom_task, which means propeller will send the request to this agent.
       - custom_task: custom_agent