this derivation will be built:
  /nix/store/1x6j8zhkydaqfsi39f4qjxbgi8v5xy8a-spec-jsonfmt.drv
building '/nix/store/1x6j8zhkydaqfsi39f4qjxbgi8v5xy8a-spec-jsonfmt.drv' on 'ssh-ng://customer@mac02.m.ntd.one'
building '/nix/store/1x6j8zhkydaqfsi39f4qjxbgi8v5xy8a-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