diff --git a/infra/deploy/env-topology.sh b/infra/deploy/env-topology.sh
index 9e2b7c9..d57d148 100644
--- a/infra/deploy/env-topology.sh
+++ b/infra/deploy/env-topology.sh
@@ -76,6 +76,16 @@ thermograph_topology() {
   # for the reason that marker was demoted to a fallback in the first place: vps2 runs
   # prod and beta side by side, and one host-wide file cannot name two backends.
   TG_SECRETS_BACKEND=sops
+  # Which AppRole credential file render-secrets-openbao.sh authenticates with. Same
+  # reasoning as TG_SECRETS_BACKEND above, and the same trap: vps2 renders TWO
+  # environments, so a single host-wide default cannot serve both. prod and dev each
+  # get the conventional path (dev is alone on vps1, so there is no collision there);
+  # beta is the one that must differ, because it shares a filesystem with prod.
+  #
+  # Without this, beta's render falls back to prod's credentials and tg-host-prod.hcl
+  # correctly denies thermograph/data/env/beta — a 403 at deploy time on the box that
+  # runs prod.
+  TG_BAO_APPROLE=/etc/thermograph/openbao-approle
 
   case "$env_name" in
     prod)
@@ -116,6 +126,10 @@ thermograph_topology() {
       # therefore prod's blast radius too (see .claude/hooks/prod-guard.sh).
       TG_SSH_HOST=169.58.46.181
       TG_SSH_TARGET=agent@169.58.46.181
+      # The one environment that cannot use the default AppRole path: it shares a
+      # filesystem with prod, so it needs its own credential file to authenticate as
+      # tg-beta rather than tg-prod. bootstrap-policies.sh installs it here.
+      TG_BAO_APPROLE=/etc/thermograph/openbao-approle-beta
       # A SECOND checkout on the same box. Separate from prod's so the two can
       # sit on different commits of this repo, and so `git reset --hard` in one
       # deploy can never yank the tree out from under the other's running
@@ -228,7 +242,7 @@ thermograph_topology() {
   export TG_LB_HTTP_PORT TG_LB_FE_PORT TG_DB_NAME TG_DB_USER
   export TG_TAGS_FILE TG_LOCK_FILE TG_BIND_ADDR TG_SKIP_COMMON
   export TG_SVC_PREFIX TG_DATA_NETWORK TG_DB_SERVICE TG_POST_DEPLOY
-  export TG_SECRETS_BACKEND
+  export TG_SECRETS_BACKEND TG_BAO_APPROLE
   export TG_SSH_HOST TG_SSH_TARGET
 }
 
diff --git a/infra/deploy/render-secrets-openbao.sh b/infra/deploy/render-secrets-openbao.sh
index 82c449c..aaf606d 100644
--- a/infra/deploy/render-secrets-openbao.sh
+++ b/infra/deploy/render-secrets-openbao.sh
@@ -27,7 +27,13 @@ thermograph_openbao_source() {
   local env_name="${1:?env name required}"
   local addr="${THERMOGRAPH_BAO_ADDR:-https://10.10.0.1:8200}"
   local mount="${THERMOGRAPH_BAO_MOUNT:-thermograph}"
-  local approle="${THERMOGRAPH_BAO_APPROLE:-/etc/thermograph/openbao-approle}"
+  # Explicit override first, then the per-environment value env-topology.sh derives,
+  # then the conventional path. Same precedence shape as render-secrets.sh:44's
+  # THERMOGRAPH_SECRETS_BACKEND / TG_SECRETS_BACKEND pair, for the same reason: the
+  # THERMOGRAPH_-prefixed name is the by-hand escape hatch, the TG_ one is what the
+  # deploy path sets. Falling straight through to the bare default is what made beta
+  # authenticate as tg-prod and get denied its own path.
+  local approle="${THERMOGRAPH_BAO_APPROLE:-${TG_BAO_APPROLE:-/etc/thermograph/openbao-approle}}"
   local ca="${THERMOGRAPH_BAO_CACERT:-/etc/thermograph/openbao-ca.crt}"
 
   command -v bao >/dev/null 2>&1 || {
diff --git a/infra/openbao/README.md b/infra/openbao/README.md
index 037bfcb..855e4d7 100644
--- a/infra/openbao/README.md
+++ b/infra/openbao/README.md
@@ -185,15 +185,14 @@ its own host:
 ```sh
 # on vps2
 infra/openbao/verify-parity.sh --env prod                          # expect 32 keys
-THERMOGRAPH_BAO_APPROLE=/etc/thermograph/openbao-approle-beta \
-  infra/openbao/verify-parity.sh --env beta                        # expect 24 keys
+infra/openbao/verify-parity.sh --env beta                          # expect 24 keys
 # on vps1
 cd /opt/thermograph-dev && infra/openbao/verify-parity.sh --env dev  # expect 12 keys
 ```
 
-The explicit `THERMOGRAPH_BAO_APPROLE` for beta is a stopgap: `env-topology.sh` does
-not yet derive the AppRole path per environment, so the renderer falls back to prod's
-credentials and `tg-host-prod.hcl` correctly denies `env/beta`.
+Beta needs no special handling: `env-topology.sh` derives `TG_BAO_APPROLE` per
+environment, so beta authenticates as `tg-beta` rather than falling back to prod's
+credentials and being denied its own path by `tg-host-prod.hcl`.
 
 `seed-from-sops.sh` reads every production secret in plaintext. Per `infra/CLAUDE.md`
 the equivalent `seed-from-live.sh` is explicitly *not for an agent to run*; this
diff --git a/infra/openbao/bootstrap.sh b/infra/openbao/bootstrap.sh
index f3d0f69..6fa199d 100755
--- a/infra/openbao/bootstrap.sh
+++ b/infra/openbao/bootstrap.sh
@@ -213,10 +213,9 @@ secrets is not for an agent to run:
 Then prove parity. NOT \`--all\` from one box: each AppRole is CIDR-bound to the host
 that legitimately renders it, so an environment can only be verified from its own host.
 
-  # here (vps2) -- beta needs its own AppRole, prod uses the default
+  # here (vps2)
   infra/openbao/verify-parity.sh --env prod                        # expect 32 keys
-  THERMOGRAPH_BAO_APPROLE=/etc/thermograph/openbao-approle-beta \\
-    infra/openbao/verify-parity.sh --env beta                      # expect 24 keys
+  infra/openbao/verify-parity.sh --env beta                        # expect 24 keys
   # on vps1
   cd /opt/thermograph-dev && infra/openbao/verify-parity.sh --env dev   # expect 12 keys