The credential gate. When multiplexing is active, a profile's secrets resolve
from a context-local scope, never the process-global os.environ (which in a
multiplexer may hold another profile's keys, and is inherited by every
subprocess spawned with env=dict(os.environ)).
- agent/secret_scope.py: get_secret() backed by a secret-scope contextvar.
FAIL-CLOSED: when multiplex is active and no scope is installed, an unscoped
read RAISES UnscopedSecretError instead of falling back to os.environ — a
missed/new call site crashes loudly at that line rather than leaking a
cross-profile value. Genuinely-global vars (HERMES_*, PATH, kanban paths,
…) keep reading os.environ via an allowlist. load_env_file/build_profile_
secret_scope parse a profile .env into an isolated dict WITHOUT mutating
os.environ. Off by default => transparent os.getenv behavior.
- hermes_cli/runtime_provider.py: all credential/provider/base-url reads go
through _getenv -> get_secret.
- agent/credential_pool.py: env fallbacks route through get_secret (the
~/.hermes/.env-first preference is preserved and already profile-correct via
the home override).
- tools/mcp_tool.py: MCP config interpolation resolves through
get_secret, so a server's picks up the routed profile's value.
- gateway/run.py: set_multiplex_active() at GatewayRunner init; per-turn .env
reload is a no-op for credentials in multiplex mode (secrets come from the
scope, not global env); _profile_runtime_scope context manager combines the
HERMES_HOME override + secret scope; _run_agent wraps _run_agent_inner in
that scope (resolved via _resolve_profile_home_for_source) when multiplexing.
Propagates into the agent worker thread for free via the existing
copy_context() in _run_in_executor_with_context.
Tests: 13 unit (fail-closed, scope isolation, global allowlist, .env parsing
without environ mutation) + 7 E2E (runtime_provider + MCP interpolation prove
two profiles isolated, unscoped read raises, globals still read environ).
Ben Barclay
f538470cf4