diff --git a/pyproject.toml b/pyproject.toml
index 97fb0bc0..ab6af3e6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,11 @@ readme = "README.md"
 license = { file = "LICENSE.txt" }
 requires-python = ">=3.11,<3.15"
 dependencies = [
-    "torch>=2.0",
+    # Skip on ppc64le: torch there comes transitively via torch-spyre's own uv
+    # source override (from-source build), not this PyPI +cpu wheel. s390x has
+    # no upstream torch wheel or from-source override either — excluded here too
+    # since this dependency can't resolve there at all.
+    "torch>=2.0; platform_machine not in 's390x, ppc64le'",
     "transformers>=5.12.1,<6.0.0",
     "sentencepiece",
     "accelerate",
diff --git a/uv.lock b/uv.lock
index c41c6d46..bb1523a6 100644
--- a/uv.lock
+++ b/uv.lock
@@ -767,8 +767,8 @@ dependencies = [
     { name = "accelerate" },
     { name = "sentence-transformers" },
     { name = "sentencepiece" },
-    { name = "torch", version = "2.13.0", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "sys_platform == 'darwin'" },
-    { name = "torch", version = "2.13.0+cpu", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "sys_platform != 'darwin'" },
+    { name = "torch", version = "2.13.0", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "platform_machine not in 's390x, ppc64le' and sys_platform == 'darwin'" },
+    { name = "torch", version = "2.13.0+cpu", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "platform_machine not in 's390x, ppc64le' and sys_platform != 'darwin'" },
     { name = "transformers" },
 ]
 
@@ -809,7 +809,7 @@ requires-dist = [
     { name = "accelerate" },
     { name = "sentence-transformers" },
     { name = "sentencepiece" },
-    { name = "torch", specifier = ">=2.0" },
+    { name = "torch", marker = "platform_machine not in 's390x, ppc64le'", specifier = ">=2.0" },
     { name = "transformers", specifier = ">=5.12.1,<6.0.0" },
 ]
 
@@ -2826,7 +2826,7 @@ resolution-markers = [
     "python_full_version < '3.12' and sys_platform == 'darwin'",
 ]
 dependencies = [
-    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.12'" },
+    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" } },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/7a/97/5a3609c4f8d58b039179648e62dd220f89864f56f7357f5d4f45c29eb2cc/scipy-1.17.1.tar.gz", hash = "sha256:95d8e012d8cb8816c226aef832200b1d45109ed4464303e997c5b13122b297c0", size = 30573822, upload-time = "2026-02-23T00:26:24.851Z" }
 wheels = [
@@ -2905,7 +2905,7 @@ resolution-markers = [
     "python_full_version == '3.12.*' and sys_platform == 'darwin'",
 ]
 dependencies = [
-    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version == '3.12.*'" },
+    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.13'" },
     { name = "numpy", version = "2.5.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.13'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/a7/25/c2700dfaf6442b4effaa91af24ebce5dc9d31bb4a69706313aae70d72cd0/scipy-1.18.0.tar.gz", hash = "sha256:67b2ad2ad54c72ca6d04975a9b2df8c3638c34ddd5b28738e94fc2b57929d378", size = 30774447, upload-time = "2026-06-19T15:01:43.456Z" }
@@ -3191,13 +3191,13 @@ resolution-markers = [
     "python_full_version < '3.12' and sys_platform == 'darwin'",
 ]
 dependencies = [
-    { name = "filelock", marker = "sys_platform == 'darwin'" },
-    { name = "fsspec", marker = "sys_platform == 'darwin'" },
-    { name = "jinja2", marker = "sys_platform == 'darwin'" },
-    { name = "networkx", marker = "sys_platform == 'darwin'" },
-    { name = "setuptools", marker = "sys_platform == 'darwin'" },
-    { name = "sympy", marker = "sys_platform == 'darwin'" },
-    { name = "typing-extensions", marker = "sys_platform == 'darwin'" },
+    { name = "filelock" },
+    { name = "fsspec" },
+    { name = "jinja2" },
+    { name = "networkx" },
+    { name = "setuptools" },
+    { name = "sympy" },
+    { name = "typing-extensions" },
 ]
 wheels = [
     { url = "https://download-r2.pytorch.org/whl/cpu/torch-2.13.0-cp311-cp311-macosx_14_0_arm64.whl", hash = "sha256:e76f9bcecc52b8ff711239a2f7547d5353df95878ab232f0773c1d95928b92f8", upload-time = "2026-07-08T12:26:13Z" },
@@ -3218,13 +3218,13 @@ resolution-markers = [
     "python_full_version < '3.12' and sys_platform != 'darwin'",
 ]
 dependencies = [
-    { name = "filelock", marker = "sys_platform != 'darwin'" },
-    { name = "fsspec", marker = "sys_platform != 'darwin'" },
-    { name = "jinja2", marker = "sys_platform != 'darwin'" },
-    { name = "networkx", marker = "sys_platform != 'darwin'" },
-    { name = "setuptools", marker = "sys_platform != 'darwin'" },
-    { name = "sympy", marker = "sys_platform != 'darwin'" },
-    { name = "typing-extensions", marker = "sys_platform != 'darwin'" },
+    { name = "filelock" },
+    { name = "fsspec" },
+    { name = "jinja2" },
+    { name = "networkx" },
+    { name = "setuptools" },
+    { name = "sympy" },
+    { name = "typing-extensions" },
 ]
 wheels = [
     { url = "https://download-r2.pytorch.org/whl/cpu/torch-2.13.0%2Bcpu-cp311-cp311-linux_s390x.whl", hash = "sha256:6e9817dbdf5ea76789babd46e457eac5bf14ff566cf85f8addbfdff2d56601ce", upload-time = "2026-07-08T19:27:52Z" },
@@ -3276,10 +3276,10 @@ resolution-markers = [
     "python_full_version < '3.12' and sys_platform == 'darwin'",
 ]
 dependencies = [
-    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.13' and sys_platform == 'darwin'" },
-    { name = "numpy", version = "2.5.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.13' and sys_platform == 'darwin'" },
-    { name = "pillow", marker = "sys_platform == 'darwin'" },
-    { name = "torch", version = "2.13.0", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "sys_platform == 'darwin'" },
+    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.13'" },
+    { name = "numpy", version = "2.5.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.13'" },
+    { name = "pillow" },
+    { name = "torch", version = "2.13.0", source = { registry = "https://download.pytorch.org/whl/cpu" } },
 ]
 wheels = [
     { url = "https://download-r2.pytorch.org/whl/cpu/torchvision-0.28.0-cp311-cp311-macosx_14_0_arm64.whl", hash = "sha256:83fe6c020866a85acd7d97deccc45ff11d66daf42916d04396a4309c66c0ccb8", upload-time = "2026-07-08T12:26:40Z" },
@@ -3300,10 +3300,10 @@ resolution-markers = [
     "python_full_version < '3.12' and sys_platform != 'darwin'",
 ]
 dependencies = [
-    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.13' and sys_platform != 'darwin'" },
-    { name = "numpy", version = "2.5.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.13' and sys_platform != 'darwin'" },
-    { name = "pillow", marker = "sys_platform != 'darwin'" },
-    { name = "torch", version = "2.13.0+cpu", source = { registry = "https://download.pytorch.org/whl/cpu" }, marker = "sys_platform != 'darwin'" },
+    { name = "numpy", version = "2.3.5", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.13'" },
+    { name = "numpy", version = "2.5.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.13'" },
+    { name = "pillow" },
+    { name = "torch", version = "2.13.0+cpu", source = { registry = "https://download.pytorch.org/whl/cpu" } },
 ]
 wheels = [
     { url = "https://download-r2.pytorch.org/whl/cpu/torchvision-0.28.0%2Bcpu-cp311-cp311-manylinux_2_28_aarch64.whl", hash = "sha256:22958193d72444ed7cbcc665ba4821a31e5279f9c4d1ad08520918b30896b78a", upload-time = "2026-07-08T12:26:39Z" },