diff --git a/bin/gs b/bin/gs
index 11a4b08..daed4f2 100755
--- a/bin/gs
+++ b/bin/gs
@@ -472,6 +472,10 @@ cmd_sync() {
   fi
   ln -sfn "$ai_bin" "$HOME/.local/bin/gentle-ai"
   ln -sfn "$bin/engram" "$HOME/.local/bin/engram"
+  # gentle-ai sync and gentle-shell setup must use the Engram built above: without
+  # it, gentle-ai's beta channel runs its own go install of the pre-v3 module path,
+  # which fails. Set here so the sync never depends on the calling shell's env.
+  export GENTLE_AI_ENGRAM_BIN="${GENTLE_AI_ENGRAM_BIN:-$bin/engram}"
 
   # New binaries are not enough: gentle-ai sync materializes the managed configs
   # (agents, skills, plugins, engram instructions) every runtime reads.
diff --git a/docs/gs-sync.md b/docs/gs-sync.md
index c8402cd..17ee3c9 100644
--- a/docs/gs-sync.md
+++ b/docs/gs-sync.md
@@ -100,10 +100,15 @@ Check: `scripts/test-engram-auto-setup.sh`.
 
 On the beta channel, `gentle-ai sync` and installs run
 `go install github.com/Gentleman-Programming/engram/cmd/engram@main`. That is the
-pre-v3 module path, so it installs Engram v1 over the v3 binary.
-`zsh/cortex-dotfiles.zsh` exports `GENTLE_AI_ENGRAM_BIN=$HOME/.local/bin/engram`,
-which makes gentle-ai use that binary instead of installing one. `gs sync`
-installs v3 at that path.
+pre-v3 module path: it fails (`missing .../cmd/engram/go.mod`) or installs
+Engram v1 over the v3 binary. `GENTLE_AI_ENGRAM_BIN` makes gentle-ai use a given
+binary instead of installing one.
+
+`gs sync` sets `GENTLE_AI_ENGRAM_BIN` to the Engram it just built before it runs
+`gentle-ai sync` and `gentle-shell --isolated setup`, so the sync does not depend
+on the calling shell (a shell opened before a dotfiles update, or a host that
+does not load them). A value already set in the environment wins.
+`zsh/cortex-dotfiles.zsh` also exports it for `gentle-ai` runs outside `gs sync`.
 
 Check: `engram version` reports 3.x after `gs sync` and after starting Pi.
 
diff --git a/tests/gs_test.sh b/tests/gs_test.sh
index 93eecf6..558b71e 100755
--- a/tests/gs_test.sh
+++ b/tests/gs_test.sh
@@ -218,6 +218,20 @@ SHELL_CLONE="$HOME/dev/gentle/gentle-shell"
 : > "$CALLS"; OUT=$(env -u GS_SKIP_AI_SYNC "$GS" sync 2>&1); rc=$?
 check "workshop sync: gentle-ai sync targets claude-code only, then gentle-shell setup on the isolated home" \
   '[ $rc -eq 0 ] && [ "$(grep -E "^gentle-ai sync|--isolated setup" "$CALLS")" = "$(printf "gentle-ai sync --agents claude-code\nlaunch %s --isolated setup" "$SHELL_CLONE")" ] && [[ "$OUT" == *"gentle-shell setup (isolated home)"*ok* ]]'
+# gentle-ai and gentle-shell setup must use the Engram gs just built, even when the
+# calling shell never exported GENTLE_AI_ENGRAM_BIN (else beta installs the pre-v3 path).
+printf '#!/bin/sh\n[ "$1" = --version ] && { echo "gentle-ai 1.0.0"; exit 0; }\necho "gentle-ai engram=${GENTLE_AI_ENGRAM_BIN:-unset}" >> "$CALLS"\n' > "$AI"
+cp "$S/node" "$T/node.real"
+printf '#!/bin/sh\necho "setup engram=${GENTLE_AI_ENGRAM_BIN:-unset}" >> "$CALLS"\nexec %s "$@"\n' "$T/node.real" > "$S/node"
+: > "$CALLS"; OUT=$(env -u GS_SKIP_AI_SYNC -u GENTLE_AI_ENGRAM_BIN "$GS" sync 2>&1)
+EB="$HOME/.local/share/gentle-ai/main/engram"
+check "workshop sync: gentle-ai sync and gentle-shell setup get GENTLE_AI_ENGRAM_BIN on the built engram" \
+  'grep -qx "gentle-ai engram=$EB" "$CALLS" && grep -qx "setup engram=$EB" "$CALLS"'
+: > "$CALLS"; OUT=$(env -u GS_SKIP_AI_SYNC GENTLE_AI_ENGRAM_BIN=/opt/e "$GS" sync 2>&1)
+check "workshop sync: an explicit GENTLE_AI_ENGRAM_BIN wins" \
+  'grep -qx "gentle-ai engram=/opt/e" "$CALLS" && grep -qx "setup engram=/opt/e" "$CALLS"'
+cp "$T/node.real" "$S/node"
+printf '#!/bin/sh\n[ "$1" = --version ] && { echo "gentle-ai 1.0.0"; exit 0; }\necho "gentle-ai $*" >> "$CALLS"\n' > "$AI"
 : > "$CALLS"; OUT=$(env -u GS_SKIP_AI_SYNC GS_SYNC_AGENTS=x "$GS" sync 2>&1)
 check "workshop sync: GS_SYNC_AGENTS overrides the claude-code default" \
   'grep -qx "gentle-ai sync --agents x" "$CALLS"'