diff --git a/.changeset/quiet-tools-rest.md b/.changeset/quiet-tools-rest.md
new file mode 100644
index 000000000..06de1397e
--- /dev/null
+++ b/.changeset/quiet-tools-rest.md
@@ -0,0 +1,5 @@
+---
+
+---
+
+Run T3 worktree dependency preparation asynchronously while retaining portable Git hook setup.
diff --git a/.githooks/README.md b/.githooks/README.md
index 5952ca25b..147308b75 100644
--- a/.githooks/README.md
+++ b/.githooks/README.md
@@ -37,6 +37,13 @@ source-identity key.
 Records package/lockfile state under `node_modules` so T3 handoff does not
 repeat an install Git already completed.
 
+When T3 launches the configured worktree setup script, it sets
+`T3CODE_DEFER_DEPENDENCY_INSTALL=1`. Cleanup still runs synchronously, while the
+setup terminal installs dependencies asynchronously with hardlink imports from
+the shared pnpm store. Raw Git worktrees still install during checkout. Their
+install failure is best-effort; T3 can request the real exit status with
+`T3CODE_WORKTREE_PREPARATION_STRICT=1` without removing the created worktree.
+
 ## `pre-commit` / `pre-push`
 
 lint-staged on commit; agent ship gate on push (see repo AGENTS.md).
diff --git a/.githooks/post-checkout b/.githooks/post-checkout
index e1fb69449..e938e7375 100755
--- a/.githooks/post-checkout
+++ b/.githooks/post-checkout
@@ -63,6 +63,13 @@ clean_ts_project_emit() {
 
 clean_ts_project_emit "$wt_root"
 
+# T3 launches the configured worktree setup command in a visible terminal. Keep
+# cleanup synchronous, but leave dependency installation to that async setup.
+if [ "${T3CODE_DEFER_DEPENDENCY_INSTALL:-0}" = "1" ]; then
+  echo "post-checkout: dependency installation deferred to T3 workspace initialization" >&2
+  exit 0
+fi
+
 # --- pnpm install when lockfile / package.json changed -----------------------
 [ -f "$wt_root/pnpm-lock.yaml" ] || exit 0
 state_file="$wt_root/node_modules/.pnpm-checkout-state"
@@ -78,5 +85,14 @@ command -v pnpm >/dev/null 2>&1 || {
 export CI=1
 echo "post-checkout: pnpm install in $wt_root" >&2
 cd "$wt_root" || exit 1
-pnpm install --frozen-lockfile --prefer-offline --config.confirmModulesPurge=false || exit $?
-printf '%s\n' "$state" >"$state_file"
+if pnpm install --frozen-lockfile --prefer-offline \
+    --config.package-import-method=hardlink \
+    --config.confirmModulesPurge=false
+then
+  printf '%s\n' "$state" >"$state_file"
+else
+  status=$?
+  echo "post-checkout: dependency preparation failed (exit $status); worktree remains usable but degraded" >&2
+  [ "${T3CODE_WORKTREE_PREPARATION_STRICT:-0}" = "1" ] && exit "$status"
+  exit 0
+fi
diff --git a/scripts/hooks/post-checkout.test.sh b/scripts/hooks/post-checkout.test.sh
index f36f7587d..1f5b10b47 100755
--- a/scripts/hooks/post-checkout.test.sh
+++ b/scripts/hooks/post-checkout.test.sh
@@ -14,7 +14,7 @@ mkdir -p .githooks "$work/fake-home/.local/bin"
 install -m 0755 "$hook" .githooks/post-checkout
 printf '{}\n' >package.json
 printf 'lockfileVersion: 9\n' >pnpm-lock.yaml
-printf '#!/bin/sh\nroot=$(git rev-parse --show-toplevel)\nmkdir -p "$root/node_modules"\ntouch "$root/node_modules/.modules.yaml"\nprintf x >>"$root/.pnpm-runs"\n' >"$work/fake-home/.local/bin/pnpm"
+printf '#!/bin/sh\nroot=$(git rev-parse --show-toplevel)\nmkdir -p "$root/node_modules"\ntouch "$root/node_modules/.modules.yaml"\nprintf x >>"$root/.pnpm-runs"\nprintf "%%s\\n" "$*" >"$root/.pnpm-args"\n' >"$work/fake-home/.local/bin/pnpm"
 chmod +x "$work/fake-home/.local/bin/pnpm"
 git add .githooks package.json pnpm-lock.yaml
 git commit -q -m init
@@ -24,6 +24,7 @@ ref=$(git -C "$work/idempotent-linked" rev-parse HEAD)
 HOME="$work/fake-home" git -C "$work/idempotent-linked" -c core.hooksPath=.githooks \
   hook run post-checkout -- "$ref" "$ref" 1
 test "$(wc -c <"$work/idempotent-linked/.pnpm-runs")" = 1
+grep -q -- '--config.package-import-method=hardlink' "$work/idempotent-linked/.pnpm-args"
 
 # Branch checkout must wipe packages/*/dist.
 git init -q "$work/ts-clean-main"
@@ -61,4 +62,23 @@ HOME="$work/fake-home" git -c core.hooksPath=.githooks \
   hook run post-checkout -- "$ref" "$ref" 0
 test -f packages/effect-app/dist/keep.d.ts
 
+# T3 may defer installation to its setup terminal. Normal Git preparation is
+# best-effort, while T3's explicit strict pass can still observe the exit code.
+printf '#!/bin/sh\ntouch "$(git rev-parse --show-toplevel)/.pnpm-attempt"\nexit 17\n' >"$work/fake-home/.local/bin/pnpm"
+chmod +x "$work/fake-home/.local/bin/pnpm"
+rm -f node_modules/.pnpm-checkout-state .pnpm-attempt
+deferred_out="$(HOME="$work/fake-home" T3CODE_DEFER_DEPENDENCY_INSTALL=1 T3CODE_WORKTREE_PREPARATION_STRICT=1 sh .githooks/post-checkout HEAD HEAD 1 2>&1)"
+case "$deferred_out" in
+  *"dependency installation deferred to T3 workspace initialization"*) ;;
+  *) exit 1 ;;
+esac
+test ! -f .pnpm-attempt
+HOME="$work/fake-home" sh .githooks/post-checkout HEAD HEAD 1 >/dev/null 2>&1
+test -f .pnpm-attempt
+set +e
+HOME="$work/fake-home" T3CODE_WORKTREE_PREPARATION_STRICT=1 sh .githooks/post-checkout HEAD HEAD 1 >/dev/null 2>&1
+strict_status=$?
+set -e
+test "$strict_status" = 17
+
 echo "portable worktree hooks passed"
diff --git a/t3.json b/t3.json
new file mode 100644
index 000000000..76f180744
--- /dev/null
+++ b/t3.json
@@ -0,0 +1,10 @@
+{
+  "$schema": "https://t3.codes/schema/t3.json",
+  "scripts": [
+    {
+      "name": "Setup Worktree",
+      "command": "pnpm install --frozen-lockfile --prefer-offline --config.package-import-method=hardlink --config.confirmModulesPurge=false",
+      "runOnWorktreeCreate": true
+    }
+  ]
+}