diff --git a/.githooks/README.md b/.githooks/README.md
index 709c179648c..3166bdc450c 100644
--- a/.githooks/README.md
+++ b/.githooks/README.md
@@ -6,6 +6,33 @@ after branch checkout and worktree creation before Git returns. T3 configures
 the hook path and triggers that checkout once for a fresh clone, before exposing
 the repository to the user.
 
+## `post-checkout`
+
+### 1. Clear TypeScript project emit (always on branch / worktree checkout)
+
+Composite packages and build outputs leave gitignored `dist/` and
+`*.tsbuildinfo`. After a branch switch those artifacts can still belong to
+another tree while sources follow HEAD. That produces phantom type errors (or
+stale emit consumers) that disappear after a clean rebuild — same class of
+failure as [scanner#1495](https://github.com/macs-holding/scanner/pull/1495) /
+[scanner#2166](https://github.com/macs-holding/scanner/pull/2166) and upstream
+typescript-go incremental gaps.
+
+On every **branch** checkout (flag `1`), this hook deletes:
+
+- `apps/*/dist`, `apps/*/dist-electron`, `packages/*/dist`
+- any remaining `*.tsbuildinfo` outside `node_modules` / `.git` / `.vite-plus`
+
+File-only checkouts (flag `0`) are left alone.
+
+**This is a workaround.** Remove when TypeScript/tsgo incremental invalidation
+is reliable ([typescript-go#2666](https://github.com/microsoft/typescript-go/issues/2666),
+[#4664](https://github.com/microsoft/typescript-go/issues/4664),
+[#4262](https://github.com/microsoft/typescript-go/issues/4262)). Do not
+re-enable cross-tree dist reuse without an exact source-identity key.
+
+### 2. Seed copy + pnpm install
+
 Successful reconciliation records the package/lockfile state under
 `node_modules`, so T3's explicit handoff invocation does not repeat an install
 which Git already completed. Explicit invocation from the target is required
diff --git a/.githooks/post-checkout b/.githooks/post-checkout
index 33bb7fd84ed..a3595e610d9 100755
--- a/.githooks/post-checkout
+++ b/.githooks/post-checkout
@@ -7,10 +7,12 @@
 # guest -- not only when a worktree is created through the T3 app / t3.json.
 #
 # Strategy (metadata-safe):
-#   1. Copy *small* gitignored seeds from .worktreeinclude (CLAUDE.md, .nuxt, …)
+#   1. Drop TypeScript project emit (dist / tsbuildinfo) so composite/incremental
+#      builds never typecheck against foreign-tree .d.ts after a branch switch.
+#   2. Copy *small* gitignored seeds from .worktreeinclude (CLAUDE.md, .nuxt, …)
 #      via reflink/hardlink when available. NEVER clone node_modules -- that
 #      creates millions of inodes per worktree on btrfs.
-#   2. Populate node_modules with `pnpm install --frozen-lockfile --prefer-offline`
+#   3. Populate node_modules with `pnpm install --frozen-lockfile --prefer-offline`
 #      against the shared store (hardlinks -> one inode per package file).
 #
 # Idempotent: never overwrites existing seed paths; pnpm is safe to re-run.
@@ -26,6 +28,52 @@ main_wt=$(git worktree list --porcelain | sed -n '1s/^worktree //p')
 wt_root=$(git rev-parse --show-toplevel 2>/dev/null)
 [ -n "$wt_root" ] || exit 0
 
+# --- TS build-cache wipe (every branch / worktree checkout) -----------------
+#
+# Composite/incremental emit (and leftover dist from builds) can outlive a
+# branch switch. Foreign .tsbuildinfo / .d.ts produce phantom type errors that
+# vanish after clean rebuild — same class as macs-holding/scanner#1495 / #2166
+# and typescript-go incremental gaps (#2666, #4664, #4262).
+# Workaround until upstream invalidation is solid; see .githooks/README.md.
+#
+clean_ts_project_emit() {
+  root=$1
+  removed=0
+
+  for d in \
+    "$root"/apps/*/dist \
+    "$root"/apps/*/dist-electron \
+    "$root"/packages/*/dist
+  do
+    [ -e "$d" ] || continue
+    rm -rf "$d"
+    removed=1
+  done
+
+  if [ -d "$root" ]; then
+    # Prune by basename so nested apps/*/node_modules are skipped too.
+    tsbuild_files=$(
+      find "$root" \
+        \( -name node_modules -o -name .git -o -name .vite-plus \) -prune -o \
+        -type f -name '*.tsbuildinfo' -print 2>/dev/null || true
+    )
+    if [ -n "$tsbuild_files" ]; then
+      printf '%s\n' "$tsbuild_files" | while IFS= read -r f; do
+        [ -n "$f" ] || continue
+        rm -f "$f"
+      done
+      removed=1
+    fi
+  fi
+
+  if [ "$removed" = 1 ]; then
+    echo "post-checkout: cleared TypeScript project emit (dist / tsbuildinfo) under $root" >&2
+    echo "post-checkout: workaround for tsgo/tsc stale incremental cache after tree switch — see .githooks/README.md (remove when upstream fixed)" >&2
+  fi
+}
+
+clean_ts_project_emit "$wt_root"
+
 if [ -n "$main_wt" ] && [ "$main_wt" != "$wt_root" ]; then
   # Effective include: repo .worktreeinclude if present, else nothing to seed-copy.
   include=""