spine-advise
spine-advise <decision-artifact> [--output <path>] requests one external
provider that is distinct from the coordinator. spine-advise --stress
requests two distinct actual external providers. It accepts a decision artifact
and optional output path. spine-council is the exact stress shorthand.
Preconditions and paths
The decision artifact must be a non-empty local file. The default output is
<input-dir>/advice.md or <input-dir>/advice-stress.md. An explicit output
must stay inside the current session directory or worktree. Write a candidate
beside the requested output, validate every required field, then replace the
output through a same-directory atomic rename.
Use native-dispatch.md for optional local evidence collection. Native collection can inform the question, but it never counts as an external opinion.