I was surprised to see that this snapcraft.yaml: name: my-snap-name # you probably want to 'snapcraft register <name>' base: core18 # the base snap is the execution environment for this snap version: '0.1' # just for humans, typically '1.2+git' or '1.3.2' summary: Single-line elevator pitch for your amazing snap # 79 char long summary description: |   This is my-snap's description. You have a paragraph or two to tell the   most important story about your snap. Keep it under 100 words though,   we live in tweetspace and your description wants to look good in the snap   store. grade: devel # must be 'stable' to release into candidate/stable channels confinement: devmode # use 'strict' once you have the right plugs and slots apps:   hello:     command: hello.sh     adapter: legacy parts:   my-part:     # See 'snapcraft plugins'     plugin: nil     override-build: |       echo "#!/bin/sh\necho 'hello'" > "$SNAPCRAFT_PART_INSTALL/hello.sh"       chmod a+x "$SNAPCRAFT_PART_INSTALL/hello.sh" Produced exactly the same priming area as the same snapcraft.yaml, but using the "full" app adapter instead. They are both what "full" should be: using the command-chain instead of generating wrappers. Not only should they not be the same, but "legacy" is still supposed to be the default, according to the schema. It means that there is no way today to generate a snap that doesn't assume command-chain.