diff --git a/tools/lazy_deps.py b/tools/lazy_deps.py
index 02e3038d4d3..3aeace33b70 100644
--- a/tools/lazy_deps.py
+++ b/tools/lazy_deps.py
@@ -174,11 +174,11 @@ LAZY_DEPS: dict[str, tuple[str, ...]] = {
         "uvicorn[standard]==0.41.0",
         "starlette==1.0.1",  # CVE-2026-48710 (BadHost) — keep lazy-install in sync with pyproject [web]
     ),
-    # Vision image-resize recovery (Pillow). Soft dependency: vision_tools and
-    # conversation_compression degrade gracefully without it, but the byte AND
-    # pixel-dimension shrink paths no-op when it's absent, so an oversized
-    # image can brick a session on Anthropic's non-retryable 400. Keep in sync
-    # with pyproject [vision].
+    # Vision image-resize recovery (Pillow). Pillow is now a CORE dependency
+    # (pyproject `dependencies`), so this entry is a belt-and-suspenders fallback
+    # for stripped/source-build installs that somehow dropped it. The vision
+    # call site uses prompt=False so it can never raise a blocking input()
+    # prompt mid-session (#40490).
     "tool.vision": ("Pillow==12.2.0",),
 }
 
diff --git a/tools/transcription_tools.py b/tools/transcription_tools.py
index 492f04cb83d..2c8b8f75fc3 100644
--- a/tools/transcription_tools.py
+++ b/tools/transcription_tools.py
@@ -214,7 +214,11 @@ def _try_lazy_install_stt() -> bool:
     """
     try:
         from tools.lazy_deps import ensure
-        ensure("stt.faster_whisper")
+        # prompt=False: never raise a blocking input() prompt mid-session.
+        # Under the interactive CLI prompt_toolkit owns stdin, so a bare
+        # input() deadlocks the terminal (#40490). The install is already
+        # gated by security.allow_lazy_installs, so reaching here is opt-in.
+        ensure("stt.faster_whisper", prompt=False)
         # Re-check dynamically after install
         import importlib.util as _iu
         if _iu.find_spec("faster_whisper"):
diff --git a/tools/vision_tools.py b/tools/vision_tools.py
index 3187f54763b..cfc933dae0f 100644
--- a/tools/vision_tools.py
+++ b/tools/vision_tools.py
@@ -422,7 +422,11 @@ def _resize_image_for_vision(image_path: Path, mime_type: Optional[str] = None,
         # the raw bytes and let the caller raise the size error.
         try:
             from tools.lazy_deps import ensure as _ensure_dep
-            _ensure_dep("tool.vision")
+            # prompt=False: never raise a blocking input() prompt mid-session.
+            # Under the interactive CLI prompt_toolkit owns stdin, so a bare
+            # input() deadlocks the terminal (#40490). The install is already
+            # gated by security.allow_lazy_installs, so reaching here is opt-in.
+            _ensure_dep("tool.vision", prompt=False)
             from PIL import Image
             import io as _io
         except Exception: