ECLAIRs is a 2D-coded mask imager sensitive from 4 to 250 keV, with a field of view of 80°x 80° and a localization accuracy better than 10', at 7 s. It will deliver triggers by seeking continuously for the appearance of new transient sources in the hard X-ray energy domain, and by determining their localization on the sky. When a new source candidate is detected, an alert will be automatically transmitted to the satellite and to the ground within 1 minute via a VHF network.

Gamma-Ray Monitor is a set of two gamma-ray spectro-photometers sensitive in the range 50 keV to 5 MeV. It will cover the same FoV than ECLAIRs and provide a measurement of the peak energy, E-peak.

X-ray Imager for Afterglow Observations is a micro-channel X-ray telescope operating from 0.3 to 7 keV, with a FOV of 1.1° and a localization accuracy better than 20'', at 5 s. It will reach a sensitivity of about 5-10 mCrab in 10 ks, at 5 s. It will provide an intermediate step between the first localizations at several arcminutes given by Eclairs and the precise localizations that can be achieved with an optical telescope. The refined position will be also transmitted via the alert network.

Visible Telescope is a 45 cm visible telescope operating from 400 to 950 nm, with a FOV of 21'x21'. It will reach a sensitivity of about 23 magnitudes, in the R band, in a 300 s exposure time, at 5 s.

After an automatic satellite slew maneuver lasting less than 5 minutes, MXT, with a sensitivity close to the Swift X-Ray Telescope, and the VT, with a sensitivity significantly improved over the Swift UVOT, completed by the two GFTs on ground, will insure a systematic multi-wavelength follow-up for several hours. In particular the VT will allow the detection of nearly 75 % of GRBs in the visible domain, during the first orbit and, for the first time, to explore the realm of ``dark GRBs''. All these instruments are included in a chain allowing a refinement of the localization, from few arcminutes to sub-arcsecondes. All these alerts will be distributed to the scientific community in real time through the GCN alert network.

A significant fraction of the time will be also available for non-GRB science like the discovery or the follow-up of cataclysmic variables, active stars, active galactic nuclei, supernovae, ... It will be possible to propose a program consisting in an observation of a given target for typically few consecutive orbits (programs maximizing the simultaneous use of several instruments will be always favored). Such a program will have always a lower priority than the GRB core program: the capabilities to detect a GRB must not be affected and the observation is stopped whenever a GRB is detected and will only resume after completion of the follow-up campaign. Target of Opportunity (ToO) observations will be also accepted for unpredictable events discovered in the routine scrutiny of the SVOM data or proposed by external partners.

A majority of bursts will be immediately observable at the end of the satellite automatic slew maneuver: about 60 % are observable "immediately" (starting observation 5 minutes after the detection, for at least 5 minutes), the rest being observable between 40 and 60 minutes later due to Earth obstruction, which may occur just few minutes after the trigger.