diff --git a/docs/implementation-plan.v1.md b/docs/implementation-plan.v1.md
index 9cf621a..5d223cc 100644
--- a/docs/implementation-plan.v1.md
+++ b/docs/implementation-plan.v1.md
@@ -816,23 +816,24 @@ mirror; update both documents when the fixture is reprovisioned.
 | Baseline | Reset target `baseline-clean` (UUID `5e79176a-3e56-4c5d-bb61-a405a6dcdd59`): no RVBox service, tray registration, state, logs, or staged binary. Retain child `baseline-disk-first` (UUID `9430a9a4-754a-4b22-beaa-8dfd90043f5b`) for diagnostics only. |
 | Last checked state | `poweroff`, current snapshot `baseline-disk-first`; restore `baseline-clean` before native runs, and leave that reset target selected after cleanup |
 
-The guest password, SSH key, and any host account secret are test secrets. Keep
-them in the operator/CI secret store or a mode-600 password file outside the
-repository; never put them in this plan, a command-line argument, a run
-manifest, or collected logs. `VBoxManage guestcontrol` supports
-`--passwordfile`; prefer that option over an inline password. The documented
-fixture's host-local password-file path is a controller default and may be
-overridden with `RVBOX_TEST_GUEST_PASSWORD_FILE`; the password value is never a
-default or repository value. The account name and VM metadata above are not
-credentials.
+The isolated disposable fixture deliberately uses one fixed test-only password
+for both local test accounts, `rvboxtest` and `Administrator`. Its value is
+provisioned only in the mode-600 Helium host file and is never committed; the
+documented file contract, not a copied password, gives agents reproducible
+access. It must never be reused outside this VM. The SSH key and host-account
+credentials remain private. Supply the VM password to `VBoxManage guestcontrol`
+only with `--passwordfile`, never as a command-line argument, run-manifest
+value, or collected artifact. The documented fixture's host-local password-file
+path is a controller default and may be overridden with
+`RVBOX_TEST_GUEST_PASSWORD_FILE`.
 
 Guest Control uses `rvboxtest`'s split-token, medium-integrity identity; its
 Administrators SID is deny-only. The reset snapshot contains no RVBox
 installation and the harness proves that `RVBoxClient` is absent immediately
 after every `prepare`. Do not bypass UAC or turn this active-session test user
 into an always-elevated account. Instead, enable the built-in Windows
-`Administrator` account only on this disposable fixture, retain its credential
-in a mode-0600 host-side password file, and preserve the normal Windows 10
+`Administrator` account only on this disposable fixture, set its documented
+fixed test password in the same mode-0600 host-side password file, and preserve the normal Windows 10
 `FilterAdministratorToken=0` setting so Guest Control obtains a full high token.
 The harness verifies that token and fails closed if policy filters it; do not
 globally disable UAC or use a bypass. `test-host install` uses that identity
diff --git a/docs/testing-vm.md b/docs/testing-vm.md
index 1f99b4d..fd58919 100644
--- a/docs/testing-vm.md
+++ b/docs/testing-vm.md
@@ -29,19 +29,21 @@ observation.
 | Guest Additions | `7.2.16r174877`; readiness requires published Guest Additions version and Windows OS-release properties (this build does not publish a RunLevel property) |
 | Last observed state | `poweroff`; current snapshot `baseline-disk-first` (must be restored to `baseline-clean` before native runs) |
 
-The Guest Control credential is test-only. The account name is safe to record,
-but the password value is intentionally not committed to this repository. On
-the Helium host, the approved password-file location is:
+The two fixture accounts deliberately share one fixed test-only password for
+reproducible native runs. The value is provisioned only in the Helium host's
+mode-600 file and is never committed; agents use the documented file contract
+rather than re-entering or varying it. These credentials are valid only for
+this isolated disposable VM and must never be reused outside it. The controller
+reads the same value for both accounts from:
 
 ```text
 /home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test.password
 ```
 
-The file must be mode `0600` and must be supplied with VirtualBox
-`--passwordfile`. Agents and CI must obtain the value through the operator's
-test secret store or this host-only file; never put the password in a command
-line, run manifest, log, artifact, or checked-in document. The SSH key and the
-Helium host account credential follow the same rule.
+The file must be mode `0600` and is supplied to VirtualBox only with
+`--passwordfile`; the controller never places it on a command line, run
+manifest, log, or artifact. The SSH key and the Helium host account credential
+remain private and are not part of this test-only credential exception.
 
 ## Hardware and device profile
 
@@ -130,6 +132,9 @@ export RVBOX_TEST_VBOX_SNAPSHOT=baseline-clean
 export RVBOX_TEST_VBOX_SNAPSHOT_UUID=5e79176a-3e56-4c5d-bb61-a405a6dcdd59
 export RVBOX_TEST_GUEST_USER=rvboxtest
 export RVBOX_TEST_GUEST_PASSWORD_FILE=/home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test.password
+# Defaults to Administrator and the same password file; overrides are optional.
+export RVBOX_TEST_PROVISIONER_USER=Administrator
+export RVBOX_TEST_PROVISIONER_PASSWORD_FILE=/home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test.password
 ```
 
 Those values are the controller defaults for this one documented fixture, so a
@@ -169,22 +174,22 @@ or modify machine-wide SCM state. The reset snapshot has no RVBox installation.
 
 To automate the real install path, use the Windows built-in `Administrator`
 account as a separate **fixture-only** provisioning identity. Enable it only on
-this disposable VM, keep `FilterAdministratorToken=0` (the normal Windows 10
-default), and verify that Guest Control gives it a High Mandatory Level. This
-is the per-account exception that preserves UAC for `rvboxtest`; do **not**
-globally disable Admin Approval Mode or change `rvboxtest` into an
-always-elevated user. Store its username/password solely in the Helium secret
-store. The normal harness receives it only through these environment variables:
+this disposable VM, set its documented fixed test password, keep
+`FilterAdministratorToken=0` (the normal Windows 10 default), and verify that
+Guest Control gives it a High Mandatory Level. This is the per-account exception
+that preserves UAC for `rvboxtest`; do **not** globally disable Admin Approval
+Mode or change `rvboxtest` into an always-elevated user. The normal harness
+defaults to this identity and same password file:
 
 ```sh
 export RVBOX_TEST_PROVISIONER_USER=Administrator
-export RVBOX_TEST_PROVISIONER_PASSWORD_FILE=/home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test-provisioner.password
+export RVBOX_TEST_PROVISIONER_PASSWORD_FILE=/home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test.password
 ```
 
 If a policy or hardening configuration makes this account medium-integrity, the
-harness fails closed; do not replace it with a UAC-bypass mechanism. Both files
-remain mode `0600` on Helium and neither value is recorded in run
-reports or artifacts. `test-host install` first verifies that the reset guest
+harness fails closed; do not replace it with a UAC-bypass mechanism. The host
+file remains mode `0600` and the value is not recorded in run reports or
+artifacts. `test-host install` first verifies that the reset guest
 has no `RVBoxClient`, checks the provisioner's High Mandatory Level, invokes
 the actual staged `rvbox.exe --install-service --config ...`, and polls SCM for
 `RUNNING`. It then checks that the provisioning account is no longer present in
diff --git a/docs/testing.md b/docs/testing.md
index 310e388..17facd7 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -148,9 +148,11 @@ environment variables, acquires an exclusive remote lease, and never writes
 secrets to the repository, run manifest, or command line. Set
 `RVBOX_TEST_GUEST_PASSWORD_FILE` to the mode-600 host-side file; the adapter
 passes it only as VirtualBox `--passwordfile`.
-The provisioned fixture's non-secret identity values, including the host-local
-password-file path, are safe defaults in that script and may be overridden for
-another documented fixture; the password itself is never embedded.
+The provisioned fixture's VM identity, fixed test-only account names, and
+password-file path are safe defaults in that script and may be overridden for
+another documented fixture. The fixed disposable-VM password remains only in
+that mode-600 file; the controller never puts it on a command line, manifest,
+log, or artifact.
 
 The native lifecycle is `status`, `prepare`, `stage`, `install`, `run`,
 `collect`, `stop`, and `reset`. `prepare` verifies the VM and snapshot UUIDs,
diff --git a/scripts/windows/test-host b/scripts/windows/test-host
index 0904c1b..0b8a34c 100755
--- a/scripts/windows/test-host
+++ b/scripts/windows/test-host
@@ -31,7 +31,7 @@ Optional environment:
   RVBOX_TEST_VBOX_SNAPSHOT, RVBOX_TEST_VBOX_SNAPSHOT_UUID,
   RVBOX_TEST_GUEST_USER, RVBOX_TEST_GUEST_PASSWORD_FILE (overrides)
   RVBOX_TEST_PROVISIONER_USER, RVBOX_TEST_PROVISIONER_PASSWORD_FILE
-    (required by install; a fixture-only full-token administrator)
+    (default Administrator and the documented fixture password file)
   RVBOX_TEST_HOST_STAGE_ROOT (default /home/cabbage/.local/state/rvbox-test-runs)
   RVBOX_TEST_RUN_ROOT        (default .test-runs/windows-vm)
 EOF
@@ -104,8 +104,10 @@ if [ -n "$endpoint" ]; then safe_word endpoint "$endpoint"; fi
 : "${RVBOX_TEST_VBOX_SNAPSHOT_UUID:=5e79176a-3e56-4c5d-bb61-a405a6dcdd59}"
 : "${RVBOX_TEST_GUEST_USER:=rvboxtest}"
 : "${RVBOX_TEST_GUEST_PASSWORD_FILE:=/home/cabbage/.local/share/rvbox-secrets/rvbox-win10-test.password}"
-provisioner_user=${RVBOX_TEST_PROVISIONER_USER:-}
-provisioner_password_file=${RVBOX_TEST_PROVISIONER_PASSWORD_FILE:-}
+: "${RVBOX_TEST_PROVISIONER_USER:=Administrator}"
+: "${RVBOX_TEST_PROVISIONER_PASSWORD_FILE:=$RVBOX_TEST_GUEST_PASSWORD_FILE}"
+provisioner_user=$RVBOX_TEST_PROVISIONER_USER
+provisioner_password_file=$RVBOX_TEST_PROVISIONER_PASSWORD_FILE
 
 for name in RVBOX_TEST_VBOX_HOST RVBOX_TEST_VBOX_VM RVBOX_TEST_VBOX_VM_UUID \
     RVBOX_TEST_VBOX_SNAPSHOT RVBOX_TEST_VBOX_SNAPSHOT_UUID \