  We investigate the imprints of accretion and dynamical friction on the
gravitational-wave signals emitted by binary black holes embedded in a scalar
dark matter cloud. As a key feature in this work, we focus on scalar fields
with a repulsive self-interaction that balances against the self-gravity of the
cloud. To a first approximation, the phase of the gravitational-wave signal
receives extra correction terms at $-3$PN, $-4$PN and $-5.5$PN orders, relative
to the prediction of vacuum general relativity, due to cloud gravity, accretion
and dynamical friction. Future observations by LISA and B-DECIGO have the
potential to detect these effects for a large range of scalar
masses~$m_\mathrm{DM}$ and self-interaction couplings~$\lambda_4$. This would
correspond to scenarios with dark matter clouds smaller than $0.1$ pc, which
would be difficult to detect by other probes.
