Great question! Here’s how to set up and use a Microsoft Teams notification block in Prefect 3.x. High-level steps 1) Create a Teams Incoming Webhook URL in Microsoft Teams - In Teams, go to the channel where you want messages posted - Click the “…” next to the channel name > Connectors (or Apps) > search for “Incoming Webhook” - Configure it, give it a name, and copy the webhook URL - Microsoft docs: Create an Incoming Webhook 2) Make sure the block type is available - If you don’t see the Microsoft Teams block, register the notifications module:

prefect block register -m prefect.blocks.notifications

- Confirm the block type slug exists:

prefect block type ls

Look for

ms-teams-webhook

(this is the slug Prefect uses) 3) Create the block (UI or Python) Option A — via Prefect UI - Generate a link to create the block:

prefect block create ms-teams-webhook

- Click the link, give the block a name (this is your

BLOCK_NAME

), and paste the Teams webhook URL Option B — via Python

from prefect.blocks.notifications import MicrosoftTeamsWebhook
from pydantic import SecretStr

teams = MicrosoftTeamsWebhook(
    url=SecretStr("<https://outlook.office.com/webhook/your-teams-webhook-url>"),
    # optional:
    # notify_type="prefect_default",  # or "info" | "success" | "warning" | "failure"
    # include_image=True,
    # wrap=True,
)
teams.save("BLOCK_NAME", overwrite=True)

4) Use the block in your code Your example is correct once the block exists:

from prefect.blocks.notifications import MicrosoftTeamsWebhook

teams_webhook_block = MicrosoftTeamsWebhook.load("BLOCK_NAME")
teams_webhook_block.notify("Hello from Prefect!")

Optional: Use this block for flow run notifications - In Prefect Cloud, create an Automation (Automations > New Automation) - Choose a trigger (e.g., Flow run fails) - Add action > Send notification > select your Microsoft Teams block - Docs: Automations in Prefect 3 Notes and tips - The block type slug is

ms-teams-webhook

(not

microsoft-teams-webhook

). - Keep your webhook URL secret—blocks are the right place to store it. - If you get “Block type not found,” run the register command above. References - Prefect Blocks overview: Blocks in Prefect 3 - Notifications API reference (includes MicrosoftTeamsWebhook): prefect.blocks.notifications