diff --git a/MANIFEST.in b/MANIFEST.in
index 3aee0bf04e..e0dcde6764 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -46,3 +46,5 @@ prune dimos/web/command-center-extension
 
 global-exclude test_*.py
 global-exclude conftest.py
+
+include dimos_build.py
diff --git a/dimos_build.py b/dimos_build.py
new file mode 100644
index 0000000000..8d2e30cfb1
--- /dev/null
+++ b/dimos_build.py
@@ -0,0 +1,36 @@
+# Copyright 2026 Dimensional Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Build-time helpers that do not import the DimOS runtime."""
+
+from pathlib import Path
+import shutil
+import subprocess
+
+
+def ensure_web_dist(root: Path) -> None:
+    """Build the web assets for Git installs and source distributions."""
+    for project, artifact in (("sdk", "sdk.js"), ("cockpit", "index.html")):
+        source = root / "web" / project
+        if (source / "dist" / artifact).is_file():
+            continue
+        deno = shutil.which("deno")
+        if deno is None:
+            raise RuntimeError(
+                "Deno is required to build DimOS web assets from source. "
+                "Run dimup setup, then retry dependency installation."
+            )
+        subprocess.run([deno, "task", "--cwd", str(source), "build"], check=True)
+        if not (source / "dist" / artifact).is_file():
+            raise RuntimeError(f"Deno build did not produce {source / 'dist' / artifact}")
diff --git a/installer/src/dimup/sdk.py b/installer/src/dimup/sdk.py
new file mode 100644
index 0000000000..f76939711b
--- /dev/null
+++ b/installer/src/dimup/sdk.py
@@ -0,0 +1,49 @@
+# Copyright 2026 Dimensional Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Read the consumer dependency policy from the selected SDK revision."""
+
+from copy import deepcopy
+from typing import Any
+
+from dimup.process import SetupError
+
+SDK_URL = "https://github.com/dimensionalOS/dimos.git"
+
+
+def consumer_policy(manifest: dict[str, Any]) -> tuple[list[str], dict[str, Any]]:
+    extras = sorted(set(manifest["project"]["optional-dependencies"]) - {"dds", "unitree-dds"})
+    if not extras:
+        raise SetupError("Selected SDK has no desktop extras.")
+    upstream = manifest.get("tool", {}).get("uv", {})
+    policy = {
+        key: deepcopy(upstream[key])
+        for key in (
+            "required-version",
+            "override-dependencies",
+            "constraint-dependencies",
+            "exclude-newer",
+            "exclude-newer-package",
+            "sources",
+            "index",
+            "extra-build-dependencies",
+            "extra-build-variables",
+        )
+        if key in upstream
+    }
+    for name, source in policy.get("sources", {}).items():
+        entries = source if isinstance(source, list) else [source]
+        if any("path" in entry or "workspace" in entry for entry in entries):
+            raise SetupError(f"Selected SDK source {name!r} requires a checkout-local dependency.")
+    return extras, policy
diff --git a/installer/src/dimup/test_sdk.py b/installer/src/dimup/test_sdk.py
new file mode 100644
index 0000000000..495b00229d
--- /dev/null
+++ b/installer/src/dimup/test_sdk.py
@@ -0,0 +1,58 @@
+# Copyright 2026 Dimensional Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pytest
+
+from dimup.process import SetupError
+from dimup.sdk import consumer_policy
+
+
+def test_consumer_policy_keeps_sdk_extras_and_sources_without_dev_groups():
+    manifest = {
+        "project": {
+            "optional-dependencies": {
+                "all": [],
+                "spot": [],
+                "learning": [],
+                "dds": [],
+                "unitree-dds": [],
+            }
+        },
+        "dependency-groups": {"docs": ["sphinx"]},
+        "tool": {
+            "uv": {
+                "sources": {"graspgenx": {"git": "https://example.com/grasp", "rev": "abc"}},
+                "override-dependencies": ["numpy>=2"],
+                "default-groups": ["docs"],
+            }
+        },
+    }
+    extras, policy = consumer_policy(manifest)
+    assert extras == ["all", "learning", "spot"]
+    assert policy == {
+        "sources": {"graspgenx": {"git": "https://example.com/grasp", "rev": "abc"}},
+        "override-dependencies": ["numpy>=2"],
+    }
+    policy["sources"]["graspgenx"]["rev"] = "changed"
+    assert manifest["tool"]["uv"]["sources"]["graspgenx"]["rev"] == "abc"
+
+
+def test_consumer_policy_rejects_nonportable_sources():
+    with pytest.raises(SetupError, match="checkout-local"):
+        consumer_policy(
+            {
+                "project": {"optional-dependencies": {"all": []}},
+                "tool": {"uv": {"sources": {"local": {"path": "../local"}}}},
+            }
+        )
diff --git a/setup.py b/setup.py
index 6eca175e1e..e2f0c441df 100644
--- a/setup.py
+++ b/setup.py
@@ -21,6 +21,11 @@
 from pybind11.setup_helpers import Pybind11Extension, build_ext
 from setuptools import find_packages, setup
 from setuptools.command.build_py import build_py as _build_py
+from setuptools.command.sdist import sdist as _sdist
+
+# PEP 517 executes this file without adding the source root to sys.path.
+sys.path.insert(0, str(Path(__file__).parent))
+from dimos_build import ensure_web_dist
 
 
 def python_is_macos_universal_binary(executable: str | None = None) -> bool:
@@ -91,6 +96,8 @@ def find_package_modules(self, package, package_dir):
         ]
 
     def run(self):
+        if not getattr(self, "editable_mode", False):
+            ensure_web_dist(Path(__file__).parent)
         super().run()
         if not getattr(self, "editable_mode", False):
             self._copy_relay_dist()
@@ -99,27 +106,6 @@ def _copy_relay_dist(self):
         src = Path(__file__).parent / "web"
         if not (src / "relay" / "main.ts").is_file():
             raise RuntimeError(f"relay sources missing at {src}; refusing to build the wheel")
-        missing = [
-            rel
-            for rel in ("cockpit/dist/index.html", "sdk/dist/sdk.js")
-            if not (src / rel).is_file()
-        ]
-        if missing:
-            # Wheels must carry the Cockpit and the SDK bundle: there is no
-            # fallback debug page, so a dist-less wheel's relay serves no UI
-            # (and /sdk.js only a build hint). Building a deliberate
-            # python-only wheel (e.g. where deno is unavailable) requires the
-            # explicit env-var opt-out, which covers both products.
-            if os.environ.get("DIMOS_ALLOW_MISSING_COCKPIT") != "1":
-                raise RuntimeError(
-                    f"web dist missing ({', '.join(missing)}); run `deno task build` "
-                    "in web/sdk and web/cockpit (or `dimos run --local-relay` from a "
-                    "checkout builds them), or set DIMOS_ALLOW_MISSING_COCKPIT=1 to "
-                    "build a UI-less wheel anyway"
-                )
-            self.warn(
-                f"web dist missing ({', '.join(missing)}); this wheel's relay will have no UI"
-            )
         dst = Path(self.build_lib) / RELAY_DIST_TARGET
         for name in RELAY_DIST_SOURCES:
             entry = src / name
@@ -139,6 +125,12 @@ def _copy_relay_dist(self):
             raise RuntimeError(f"relay copy did not produce {dst / 'relay' / 'main.ts'}")
 
 
+class sdist(_sdist):
+    def run(self):
+        ensure_web_dist(Path(__file__).parent)
+        super().run()
+
+
 extra_compile_args = [
     "-O3",  # Maximum optimization
     "-ffast-math",  # Fast floating point
@@ -166,5 +158,5 @@ def _copy_relay_dist(self):
     packages=find_packages(),
     package_dir={"": "."},
     ext_modules=ext_modules,
-    cmdclass={"build_ext": build_ext, "build_py": build_py},
+    cmdclass={"build_ext": build_ext, "build_py": build_py, "sdist": sdist},
 )
diff --git a/tests/packaging/test_source_build.py b/tests/packaging/test_source_build.py
new file mode 100644
index 0000000000..68e64bf024
--- /dev/null
+++ b/tests/packaging/test_source_build.py
@@ -0,0 +1,51 @@
+# Copyright 2026 Dimensional Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from pathlib import Path
+import subprocess
+
+import pytest
+
+from dimos_build import ensure_web_dist
+
+
+def test_bundled_assets_need_no_deno(tmp_path, monkeypatch):
+    for project, artifact in (("sdk", "sdk.js"), ("cockpit", "index.html")):
+        dist = tmp_path / "web" / project / "dist"
+        dist.mkdir(parents=True)
+        (dist / artifact).write_text("built")
+    monkeypatch.setattr("shutil.which", lambda name: None)
+    ensure_web_dist(tmp_path)
+
+
+def test_missing_deno_explains_machine_setup(tmp_path, monkeypatch):
+    monkeypatch.setattr("shutil.which", lambda name: None)
+    with pytest.raises(RuntimeError, match="dimup setup"):
+        ensure_web_dist(tmp_path)
+
+
+def test_source_build_produces_both_bundles(tmp_path, monkeypatch):
+    commands = []
+
+    def build(command, *, check):
+        commands.append(command)
+        project = Path(command[3])
+        dist = project / "dist"
+        dist.mkdir(parents=True)
+        (dist / ("sdk.js" if project.name == "sdk" else "index.html")).write_text("built")
+
+    monkeypatch.setattr("shutil.which", lambda name: "/bin/deno")
+    monkeypatch.setattr(subprocess, "run", build)
+    ensure_web_dist(tmp_path)
+    assert [Path(command[3]).name for command in commands] == ["sdk", "cockpit"]