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Hey team! Im trying to use the `on_failure` callback of a flow to send a message to a slack channel that ideally looks something like “OH MAN THE FLOW FAILED - Click here to see the flow” with a proper link. Does the flow object contain any information I can use to construct a useful URL, specifically the flow_id?

Why not use the `slack_notifier` state handler instead?
<https://docs.prefect.io/core/advanced_tutorials/slack-notifications.html|https://docs.prefect.io/core/advanced_tutorials/slack-notifications.html>

You can set it to notify only on failed states, and it comes packaged with the URL you have in mind.

Ah this is a farrrr superior solution, Ive been working off this page (<https://docs.prefect.io/core/concepts/notifications.html#responding-to-state>) with the slack examples, had no idea they had other better slack examples hidden away! Thanks Amanda, really appreciate it!

<@U01DJDK6AQ7> Im hoping youve used the slack notifier before, so running this with you before I raise a bug report:

The slack notifier works when you attach it as a state_handler, but does not work when you attach it via `on_failure`. I cant see this caveat documented and it certainly seems unintuitive given the on_failure was meant to be a subset of state_handler

I've used `slack_notifier`, but not with `on_failure`, so I'm afraid that I can't say anything about that.

Okay, a quick check of the API explains why: the signature of the callback expected for a state handler is different from the signature of the callback expected for `on_failure`, i.e., a generic state handler must accept both old state and new state, whereas on failure the callback only needs to accept the new state, i.e., the specific failure state.

Ah that does make sense. Thanks for the help :slightly_smiling_face: