TITLE: GCN CIRCULAR NUMBER: 26123 SUBJECT: GRB 191031D: AGILE/MCAL observations DATE: 19/11/01 09:11:45 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), report on behalf of the AGILE Team: The AGILE Mini-CALorimeter (MCAL) detected the short GRB 191031D at T0 = 2019-10-31 21:23:28.17 +/- 0.01 s (UTC), already detected by Fermi/GBM (GCN #26111), Swift (D'Elia et al., 2019; GCN #26112), and INTEGRAL/SPIACS (trignum=8402). The event lasted about 0.2 s and released a total number of ~430 counts in the detector (in the 0.4-100 MeV energy range), above an average background rate of 544 counts / s. The light curve shows a single peak episode and can be found at http://www.agilescienceapp.it/notices/GRB_064997_499641808.174626.png. The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.