diff --git a/nixos/tests/home-assistant.nix b/nixos/tests/home-assistant.nix
index e1588088ba19..9200723f35e7 100644
--- a/nixos/tests/home-assistant.nix
+++ b/nixos/tests/home-assistant.nix
@@ -43,7 +43,7 @@ in {
 
       # test loading custom components
       customComponents = with pkgs.home-assistant-custom-components; [
-        prometheus-sensor
+        prometheus_sensor
       ];
 
       # test loading lovelace modules
diff --git a/pkgs/servers/home-assistant/build-custom-component/check_manifest.py b/pkgs/servers/home-assistant/build-custom-component/check_manifest.py
index bbe9535824e7..463a7579763d 100644
--- a/pkgs/servers/home-assistant/build-custom-component/check_manifest.py
+++ b/pkgs/servers/home-assistant/build-custom-component/check_manifest.py
@@ -1,28 +1,31 @@
 #!/usr/bin/env python3
 
 import json
-import importlib_metadata
+import os
 import sys
 
+import importlib_metadata
 from packaging.requirements import Requirement
 
 
+def error(msg: str) -> None:
+    print(f"  - {msg}", file=sys.stderr)
+    return False
+
+
 def check_requirement(req: str):
     # https://packaging.pypa.io/en/stable/requirements.html
     requirement = Requirement(req)
     try:
         version = importlib_metadata.distribution(requirement.name).version
     except importlib_metadata.PackageNotFoundError:
-        print(f"  - Dependency {requirement.name} is missing", file=sys.stderr)
-        return False
+        return error(f"{requirement.name}{requirement.specifier} not present")
 
     # https://packaging.pypa.io/en/stable/specifiers.html
-    if not version in requirement.specifier:
-        print(
-            f"  - {requirement.name}{requirement.specifier} expected, but got {version}",
-            file=sys.stderr,
+    if version not in requirement.specifier:
+        return error(
+            f"{requirement.name}{requirement.specifier} expected, but got {version}"
         )
-        return False
 
     return True
 
@@ -30,13 +33,24 @@ def check_requirement(req: str):
 def check_manifest(manifest_file: str):
     with open(manifest_file) as fd:
         manifest = json.load(fd)
+
+    ok = True
+
+    derivation_domain = os.environ.get("domain")
+    manifest_domain = manifest["domain"]
+    if derivation_domain != manifest_domain:
+        ok = False
+        error(
+            f"Derivation attribute domain ({derivation_domain}) must match manifest domain ({manifest_domain})"
+        )
+
     if "requirements" in manifest:
-        ok = True
         for requirement in manifest["requirements"]:
             ok &= check_requirement(requirement)
-        if not ok:
-            print("Manifest requirements are not met", file=sys.stderr)
-            sys.exit(1)
+
+    if not ok:
+        error("Manifest check failed.")
+        sys.exit(1)
 
 
 if __name__ == "__main__":
diff --git a/pkgs/servers/home-assistant/build-custom-component/default.nix b/pkgs/servers/home-assistant/build-custom-component/default.nix
index 05b7c2d4b039..2948d15bb814 100644
--- a/pkgs/servers/home-assistant/build-custom-component/default.nix
+++ b/pkgs/servers/home-assistant/build-custom-component/default.nix
@@ -3,7 +3,8 @@
 , makeSetupHook
 }:
 
-{ pname
+{ owner
+, domain
 , version
 , format ? "other"
 , ...
@@ -17,13 +18,14 @@ let
 in
 home-assistant.python.pkgs.buildPythonPackage (
   {
+    pname = "${owner}/${domain}";
     inherit format;
 
     installPhase = ''
       runHook preInstall
 
       mkdir $out
-      cp -r $src/custom_components/ $out/
+      cp -r ./custom_components/ $out/
 
       runHook postInstall
     '';
diff --git a/pkgs/servers/home-assistant/custom-components/README.md b/pkgs/servers/home-assistant/custom-components/README.md
index a7244b25c173..d7137e5c62f7 100644
--- a/pkgs/servers/home-assistant/custom-components/README.md
+++ b/pkgs/servers/home-assistant/custom-components/README.md
@@ -25,7 +25,7 @@ versions into the Python environment.
 }:
 
 buildHomeAssistantComponent {
-  # pname, version
+  # owner, domain, version
 
   src = fetchFromGithub {
     # owner, repo, rev, hash
@@ -40,18 +40,34 @@ buildHomeAssistantComponent {
   }
 }
 
-## Package name normalization
+## Package attribute
 
-Apply the same normalization rules as defined for python packages in
-[PEP503](https://peps.python.org/pep-0503/#normalized-names).
-The name should be lowercased and dots, underlines or multiple
-dashes should all be replaced by a single dash.
+The attribute name must reflect the domain as seen in the
+`manifest.json`, which in turn will match the python module name below
+in the `custom_components/` directory.
+
+**Example:**
+
+The project [mweinelt/ha-prometheus-sensor](https://github.com/mweinelt/ha-prometheus-sensor/blob/1.0.0/custom_components/prometheus_sensor/manifest.json#L2)
+would receive the attribute name `"prometheus_sensor"`, because both
+domain in the `manifest.json` as well as the module name are
+`prometheus_sensor`.
+
+## Package name
+
+The `pname` attribute is a composition of both `owner` and `domain`.
+
+Don't set `pname`, set `owner and `domain` instead.
+
+Exposing the `domain` attribute separately allows checking for
+conflicting components at eval time.
 
 ## Manifest check
 
 The `buildHomeAssistantComponent` builder uses a hook to check whether
 the dependencies specified in the `manifest.json` are present and
-inside the specified version range.
+inside the specified version range. It also makes sure derivation
+and manifest agree about the domain name.
 
 There shouldn't be a need to disable this hook, but you can set
 `dontCheckManifest` to `true` in the derivation to achieve that.
diff --git a/pkgs/servers/home-assistant/custom-components/default.nix b/pkgs/servers/home-assistant/custom-components/default.nix
index 4a96b305964a..15bd721c72e8 100644
--- a/pkgs/servers/home-assistant/custom-components/default.nix
+++ b/pkgs/servers/home-assistant/custom-components/default.nix
@@ -2,5 +2,5 @@
 }:
 
 {
-  prometheus-sensor = callPackage ./prometheus-sensor {};
+  prometheus_sensor = callPackage ./prometheus_sensor {};
 }
diff --git a/pkgs/servers/home-assistant/custom-components/prometheus-sensor/default.nix b/pkgs/servers/home-assistant/custom-components/prometheus_sensor/default.nix
similarity index 92%
rename from pkgs/servers/home-assistant/custom-components/prometheus-sensor/default.nix
rename to pkgs/servers/home-assistant/custom-components/prometheus_sensor/default.nix
index 07bcd9abec1c..2368d85552b2 100644
--- a/pkgs/servers/home-assistant/custom-components/prometheus-sensor/default.nix
+++ b/pkgs/servers/home-assistant/custom-components/prometheus_sensor/default.nix
@@ -4,7 +4,8 @@
 }:
 
 buildHomeAssistantComponent rec {
-  pname = "prometheus-sensor";
+  owner = "mweinelt";
+  domain = "prometheus_sensor";
   version = "1.0.0";
 
   src = fetchFromGitHub {