Configure the public base URL of your web server: config plugins.grapnel.baseurl https://address.of.your.bot
Create a webhook: grapnel add [network] [channel]
- network and channel default to the current network and channel, if you run this command in a channel.
Save the URL generated and plug it into whatever app you want to announce events from.
- Replace your-cool-app-name with the name of the sending app; it will be reflected in the output by default
- Make sure to keep this link private, as it includes the token!
Test the webhook: e.g.

$ curl -X POST -d '{"text": "hello world"}' -H 'Content-type: application/json' 'https://address.of.your.bot/grapnel/1?token=xxxxxx&sender=myapp'

grapnel add [<network>] [<channel>] -- Creates a new Slack-compatible webhook endpoint for a given network + channel. network and channel default to the current network and channel if not specified.
grapnel get <webhook ID> -- Returns metadata and the URL for the webhook ID.
grapnel listhooks [<network>] [<channel>] -- Lists webhooks set on the network + channel pair. network and channel default to the current network and channel if not specified.
grapnel remove <webhook ID> -- Removes the given webhook ID.
grapnel resettoken <webhook ID> -- Regenerates the token for the given webhook ID.

The plugins.grapnel.format option can be adjusted to change the output format. It supports these fields: