# Entry-Point Runtime — Elixir / Erlang (BEAM)

## Signals to gather
- `argv0` equals `elixir`, `iex`, `mix`, `erl`, `beam.smp`, or release scripts (`bin/app start`).
- Release layouts: `_build/prod/rel/<app>/bin/<app>`, `releases/<version>/vm.args`, `sys.config`.
- Environment variables (`MIX_ENV`, `RELEASE_COOKIE`, `RELEASE_NODE`).
- Config files (`config/config.exs`, `config/prod.exs`).

## Implementation notes
- Recognise Distillery / mix release scripts that `exec` the real BEAM VM.
- When release script is invoked with `eval`, treat the wrapper as part of the chain but classify runtime as `Elixir`.
- Inspect `vm.args` for node name, cookie, and distributed settings.
- For pure Erlang services (no Elixir), the same detector should fire using `erl` hints.

## Evidence & scoring
- Boost for release directories and BEAM VM binaries (`beam.smp`).
- Add evidence for config files and env vars.
- Penalise minimal images lacking release artefacts (could be generic shell wrappers).

## Edge cases
- Phoenix apps often rely on `bin/server` wrapper—ShellFlow must collapse to release script.
- Multi-node clusters may start multiple BEAM instances; treat as `Supervisor` if several nodes stay active.