prefect automation ls fails with ValidationError when an automation includes the Send Email action (send-email-notification) on 3.4.20 (Cloud)

[zzstoatzz]

This discussion was created from a Slack thread conversation.

Original Thread: https://prefect-community.slack.com/archives/C04DZJC94DC/p1759348193259749

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Environment

• Prefect CLI/SDK: 3.4.20 (Python 3.12)
• Backend: Prefect Cloud

Summary
Running prefect automation ls fails with a Pydantic ValidationError when any automation in the workspace includes the Send Email action created via the Cloud UI. The action serializes as send-email-notification. The 3.4.20 client appears to lack this action type in its automation action union, causing deserialization to fail.

Reproduction

1. In Prefect Cloud UI, create an Automation with a Send Email action (created on Sep 28, 2025 in this case).
2. From a local environment with Prefect 3.4.20, run:

prefect automation ls

3. Observe the CLI fails with a Pydantic ValidationError.

Observed error (truncated)

Traceback (most recent call last):
  ...
  File ".../prefect/client/orchestration/_automations/client.py", line 204, in read_automations
    return Automation.model_validate_list(response.json())
  ...
pydantic_core._pydantic_core.ValidationError: 17 validation errors for Automation
actions.1.DoNothing.type
  Input should be 'do-nothing' [type=literal_error, input_value='send-email-notification', input_type=str]
    For further information visit https://errors.pydantic.dev/2.11/v/literal_error

Impact

• prefect automation ls fails entirely if any automation includes the Send Email action. Removing that action from the automation allows ls to succeed again.
• Likely also affects prefect automation inspect for the impacted automation(s).

Expected

• The CLI should recognize the send-email-notification action type (or otherwise tolerate/ignore unknown action types) and list automations successfully.

Notes / Hypothesis

• The SDK exposes a SendNotification action (class prefect.events.actions.SendNotification), but the server returns send-email-notification. This suggests a client/server schema mismatch introduced after 3.4.20 was released (automation was created Sep 28, 2025; 3.4.20 released Sep 25, 2025).
• Fix likely involves adding send-email-notification to the client-side action union or aliasing it to SendNotification.

Workarounds

• Manage automations from the UI.
• Temporarily remove the Send Email action from automations to allow prefect automation ls to work.
• Use prefect automation inspect for unaffected automations, or call the REST API directly to bypass client-side model validation.

Request

• Patch release of the Python client to recognize send-email-notification (or to be resilient to unknown action types) so the CLI can list automations when this action is present.

Related docs

• Actions API: https://docs-3.prefect.io/v3/api-ref/python/prefect-events-actions
• Automation CLI: https://docs-3.prefect.io/v3/api-ref/cli/automation

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