The desktop backend ticks EVERY local profile's cron store from one process — its own docstring
says "like a multiplex gateway" (hermes_cli/web_server.py) — but never sets the process-global
multiplex flag, and cannot: its own chat turns are unscoped and would fail closed. Every
isolation in the tree keys on that flag — the guard that keeps a routed `.env` out of the shared
`os.environ`, `get_secret`'s fail-closed miss, passthrough resolution, the MCP and kanban
subprocess scrubs — so all of it was inert for a sibling profile's fire. Verified: a secondary
profile's API keys replaced the launch profile's in `os.environ` with `override=True` and stayed
there after the tick, and a scope miss read the launch profile's tokens (#107692).
Give multiplex mode a context-local counterpart. `set_multiplex_context` (agent/secret_scope.py)
is OR'd into `is_multiplex_active()`. `_profile_cron_scope` only MARKS a fire whose home is not
the process's own (`routed_profile_fire`, decided against `get_process_hermes_home()`, the
override-immune resolver); `_install_fire_secret_scope` in cron/scheduler.py installs the
profile's hydrated secret scope and, for a marked fire, the multiplex context — for exactly that
span, dropped again before the scope by `_reset_fire_secret_scope`. Multiplex semantics are
therefore never active in cron without a scope to read: `run_one_job`'s restart-safe handoff runs
before the body's scope and keeps today's semantics (its own scope is #107413 / #106050's seam,
left untouched so this composes with whichever lands). Every existing multiplex-keyed isolation
applies inside the routed fire with no per-site patching; the launch profile's own fires and the
backend's turns keep single-profile semantics; marker and override both reach the pool worker via
`copy_context()`. `get_secret` read the raw global in its miss branch; it now goes through
`is_multiplex_active()`. The dotenv guard keeps its pinned flag-only form (#77970).
Two consequences of suppressing the write are handled rather than left as regressions:
- a `no_agent` script's env is `os.environ.copy()`, which no longer carries the routed `.env`;
the runner overlays the installed scope onto the base BEFORE sanitizing, so the same scrub /
passthrough rules apply to those values and the parent process is never mutated;
- plugin secret sources are discovered on the fire's first agent build, after the scope froze,
and the post-discovery reload is hydrate-only under multiplex semantics; the refresh now folds
the values into the installed scope in place (`refresh_installed_secret_scope`, the pattern
`_publish_env_value` already uses for `.env` writes under multiplex).
And the profile's external secret sources are hydrated before the scope is frozen, the order
gateway/run.py and the external cron worker already use.
Tests pin each direction: the marker without the semantics before the scope, the semantics on and
off exactly with it, the marker reaching a copy_context worker; the process's own profile staying
single-profile; the restart-safe handoff's child env building without raising under a routed tick
with a passthrough key registered; a real child process receiving the routed values while
`os.environ` keeps the launch value; a source registered after the freeze reaching the fire
through the real PluginManager refresh. Reverting any one direction fails a distinct test.
(cherry picked from commit 2f87677425d2cca19286ac83bc45cab23e546669)
John Paul Soliva
dbede34f6e