this derivation will be built:
  /nix/store/b8zjdnv423gqrvpbj8rh3m7pl0bsiq50-spec-jsonfmt.drv
building '/nix/store/b8zjdnv423gqrvpbj8rh3m7pl0bsiq50-spec-jsonfmt.drv' on 'grpc://farm.numtide.com:50051?client-cert=/run/secrets/vars/per-machine/bld1/nix-farm-ci/crt&client-key=/run/secrets/vars/per-machine/bld1/nix-farm-ci/key&connect-timeout=20&system=aarch64-linux'
warning: b8zjdnv423gqrvpbj8rh3m7pl0bsiq50-spec-jsonfmt.drv: no connected, non-draining worker for system 'aarch64-linux' offers features {}, the workers offer {}, waiting up to 120s for a worker
building '/nix/store/b8zjdnv423gqrvpbj8rh3m7pl0bsiq50-spec-jsonfmt.drv' on farm.numtide.com:50051
spec-jsonfmt> elastic-arm-92a21b22: building b8zjdnv423gqrvpbj8rh3m7pl0bsiq50-spec-jsonfmt.drv
spec-jsonfmt> Error: failed to format json file: invalid/a.json: invalid character ',' looking for beginning of object key string
spec-jsonfmt> Error: failed to format json file: invalid/a.json: invalid character ',' looking for beginning of object key string

upload niks3: ok