Call the Mastodon REST API with curl + jq. Two connector credentials are injected: $MASTODON_BASE_URL (the instance, e.g. https://mastodon.social) and $MASTODON_ACCESS_TOKEN. Every request sends the header Authorization: Bearer $MASTODON_ACCESS_TOKEN.

Errors come back as JSON {"error":"<message>"} — show it verbatim. 401 ("The access token is invalid") means the token is wrong/revoked → the user must re-connect the Mastodon connector. Posting needs the token to have the write (or write:statuses) scope.

Always confirm the token + account first (also gives the account id you need to list your own toots):

curl -sS "$MASTODON_BASE_URL/api/v1/accounts/verify_credentials" \
  -H "Authorization: Bearer $MASTODON_ACCESS_TOKEN" \
  | jq '{id, username, acct, display_name, followers: .followers_count, statuses: .statuses_count}'