Get a Slack Message When an Agent Writes a File

An agent writes a report and the sandbox ends. The team does not see the file unless someone goes looking.

mountable.io is a persistent filesystem for AI agents. The file is still there.

What Slack shows

Slack gets one line, created /notes/report.md.

A later write is updated /notes/report.md. A rename is two lines, deleted for the old path and created for the new one. A delete is deleted /notes/report.md.

A receiver posts that path

A small receiver checks the signature on the raw request. It posts the path to a Slack incoming webhook you create.

The first delivery is an opening check. The receiver answers it and stays quiet.

Run the two commands

The Slack cookbook covers the account, the public address and the signing secret. From the example:

export SLACK_WEBHOOK_URL="https://hooks.slack.com/services/..."
export MOUNTABLE_WEBHOOK_SECRET="$(mountable webhooks create "$FS_ID" https://example.com/hooks/mountable --path-prefix /notes)"
python3 receiver.py

printf 'ready\n' | mountable files write "$FS_ID" notes/report.md --if-none-match

The first block starts the receiver. The second writes the file. Slack gets the line.

We maintain this example for mountable.io. It is not a Slack app. It uses your existing account and the incoming webhook you create.