diff --git a/apps/api/src/services/build/manifest_compiler.py b/apps/api/src/services/build/manifest_compiler.py
index 605edaa..a82e4b7 100644
--- a/apps/api/src/services/build/manifest_compiler.py
+++ b/apps/api/src/services/build/manifest_compiler.py
@@ -571,6 +571,10 @@ def get_manifest_home_dir(manifest: dict) -> str:
 def compute_image_tag(tool_name: str, manifest: dict) -> str:
     """Compute a deterministic image tag from manifest content.
 
+    The hash includes the manifest JSON plus a compiler version token so
+    that changes to the Dockerfile/entrypoint generation logic invalidate
+    previously built images.
+
     Args:
         tool_name: Human-readable tool name.
         manifest: Fully resolved manifest JSON.
@@ -578,9 +582,11 @@ def compute_image_tag(tool_name: str, manifest: dict) -> str:
     Returns:
         Docker image tag string.
     """
-    # Canonicalize: sort keys, stable JSON
+    compiler_version = "v2"  # bump when compile_dockerfile/entrypoint/compose change
     canonical = json.dumps(manifest, sort_keys=True, separators=(",", ":"))
-    hash_suffix = hashlib.sha256(canonical.encode()).hexdigest()[:8]
+    hash_suffix = hashlib.sha256(
+        f"{compiler_version}:{canonical}".encode()
+    ).hexdigest()[:8]
     safe_name = tool_name.lower().replace(" ", "-").replace("_", "-")
     return f"headquarter/{safe_name}-{hash_suffix}:latest"