diff --git a/src/specify_cli/bundles/manifest.py b/src/specify_cli/bundles/manifest.py
index 179abebd12..2811a31b96 100644
--- a/src/specify_cli/bundles/manifest.py
+++ b/src/specify_cli/bundles/manifest.py
@@ -211,6 +211,17 @@ def structural_errors(self) -> list[str]:
                 errors.append(
                     f"{ref.kind[:-1]} '{ref.id}' has invalid version '{ref.version}'."
                 )
+            # Preset and extension installs refuse a priority below 1, which
+            # would otherwise surface only mid-install, after earlier components.
+            if (
+                ref.kind in ("extensions", "presets")
+                and ref.priority is not None
+                and ref.priority < 1
+            ):
+                errors.append(
+                    f"{ref.kind[:-1]} '{ref.id}' priority must be 1 or higher, "
+                    f"got {ref.priority}."
+                )
 
         for ref in self.presets:
             if ref.priority is None:
diff --git a/tests/contract/test_manifest_schema.py b/tests/contract/test_manifest_schema.py
index edad666ebb..b4ff75be4e 100644
--- a/tests/contract/test_manifest_schema.py
+++ b/tests/contract/test_manifest_schema.py
@@ -100,6 +100,26 @@ def test_non_integer_priority_raises_actionable_error():
         BundleManifest.from_dict(data)
 
 
+@pytest.mark.parametrize(
+    ("kind", "priority"), [("presets", 0), ("presets", -3), ("extensions", 0)]
+)
+def test_non_positive_priority_is_rejected(kind, priority):
+    """Preset and extension installs reject a priority below 1, so validation must too."""
+    data = valid_manifest_dict()
+    data["provides"][kind][0]["priority"] = priority
+    errors = BundleManifest.from_dict(data).structural_errors()
+    assert any(
+        "priority must be 1 or higher" in e and f"got {priority}" in e for e in errors
+    ), errors
+
+
+@pytest.mark.parametrize("kind", ["presets", "extensions"])
+def test_priority_of_one_is_accepted(kind):
+    data = valid_manifest_dict()
+    data["provides"][kind][0]["priority"] = 1
+    assert BundleManifest.from_dict(data).structural_errors() == []
+
+
 def test_non_step_components_must_be_pinned():
     data = valid_manifest_dict()
     data["provides"]["extensions"] = [{"id": "ext-unpinned"}]
diff --git a/tests/specify_cli/bundles/test_command_install.py b/tests/specify_cli/bundles/test_command_install.py
index 2f54f051de..ad50c6f8ae 100644
--- a/tests/specify_cli/bundles/test_command_install.py
+++ b/tests/specify_cli/bundles/test_command_install.py
@@ -147,6 +147,37 @@ def test_local_bundle_rejects_mismatched_bundled_workflow_pin_offline(project: P
     assert not (project / ".specify" / "workflows" / "bugfix").exists()
 
 
+def test_local_bundle_with_non_positive_priority_is_rejected_before_any_install(
+    project: Path,
+):
+    """A priority the preset installer refuses must fail before earlier components install."""
+    bundle_dir = project / "zero-priority"
+    bundle_dir.mkdir()
+    (bundle_dir / "bundle.yml").write_text(
+        yaml.safe_dump(
+            valid_manifest_dict(
+                provides={
+                    "extensions": [
+                        {"id": "bug", "version": bundled_extension_version("bug")}
+                    ],
+                    "presets": [
+                        {"id": "lean", "version": "1.0.0", "priority": 0, "strategy": "replace"}
+                    ],
+                }
+            )
+        ),
+        encoding="utf-8",
+    )
+
+    result = runner.invoke(app, ["bundle", "install", str(bundle_dir), "--offline"])
+
+    assert result.exit_code == 1
+    assert "preset 'lean' priority must be 1 or higher, got 0" in " ".join(
+        result.output.split()
+    )
+    assert not (project / ".specify" / "extensions").exists()
+
+
 def test_local_bundle_refuses_unbundled_workflow_offline(project: Path):
     bundle_dir = project / "unbundled-workflow"
     (bundle_dir / "bundle.yml").parent.mkdir()
diff --git a/tests/specify_cli/bundles/test_command_validate.py b/tests/specify_cli/bundles/test_command_validate.py
index d09f7a4d66..a2d57913e9 100644
--- a/tests/specify_cli/bundles/test_command_validate.py
+++ b/tests/specify_cli/bundles/test_command_validate.py
@@ -47,6 +47,33 @@ def test_validate_bundled_patch_compatibility(
     assert ("newer packaged patch" in " ".join(result.output.split())) is warning
 
 
+def test_validate_rejects_non_positive_preset_priority(project: Path, monkeypatch):
+    """A manifest every install would reject must not be reported as valid."""
+    import specify_cli._assets as assets
+
+    payload = project / "packaged-preset"
+    payload.mkdir()
+    (payload / "preset.yml").write_text(
+        yaml.safe_dump({"preset": {"id": "p", "version": "1.0.0"}}), encoding="utf-8",
+    )
+    monkeypatch.setattr(assets, "_locate_bundled_preset", lambda cid: payload)
+    data = valid_manifest_dict(
+        provides={
+            "presets": [
+                {"id": "p", "version": "1.0.0", "priority": 0, "strategy": "replace"}
+            ]
+        },
+    )
+    (project / "bundle.yml").write_text(yaml.safe_dump(data), encoding="utf-8")
+
+    result = runner.invoke(app, ["bundle", "validate", "--offline"])
+
+    assert result.exit_code == 1, result.output
+    assert "preset 'p' priority must be 1 or higher, got 0" in " ".join(
+        result.output.split()
+    )
+
+
 @pytest.mark.parametrize("offline", [False, True])
 def test_validate_bundled_workflow_patch_warns_without_catalog_lookup(
     project: Path, monkeypatch, offline: bool,