diff --git a/.grit/.gitignore b/.grit/.gitignore
new file mode 100644
index 00000000000..e4fdfb17c16
--- /dev/null
+++ b/.grit/.gitignore
@@ -0,0 +1,2 @@
+.gritmodules*
+*.log
diff --git a/.grit/grit.yaml b/.grit/grit.yaml
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index 00000000000..865cd4367e9
--- /dev/null
+++ b/.grit/grit.yaml
@@ -0,0 +1,3 @@
+version: 0.0.1
+patterns:
+#  - name: github.com/getgrit/stdlib#*
diff --git a/.grit/patterns/runtime_data_migration.md b/.grit/patterns/runtime_data_migration.md
new file mode 100644
index 00000000000..5bdb48c5334
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+++ b/.grit/patterns/runtime_data_migration.md
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+---
+tags: [migration, code_quality]
+---
+# Migrate integration from hass.data to entry.runtime_data
+
+Migrate an integration from hass.data to entry.runtime_data
+
+```grit
+engine marzano(0.1)
+language python
+
+pattern refactor_functions($config_entry_type) {
+    function_definition($parameters, $body) where {
+        // change entry type
+        $entry = $parameters[1],
+        $entry <: typed_parameter(name=$entry_name, $type) where {
+            $type <: type(type="ConfigEntry"),
+            $type => $config_entry_type
+        },
+
+        // migrate hass.data to entry.runtime_data
+        $body <: maybe contains assignment($left, right=$runtime_data) as $assignment where {
+            $runtime_data <: `hass.data[$_][entry.entry_id]`,
+            $assignment => `$left = $entry_name.runtime_data`
+        },
+    }
+}
+
+pattern refactor_init($config_entry_type) {
+    function_definition(name="async_setup_entry", $parameters, $body) as $func where {
+        // change entry type
+        $entry = $parameters[1],
+        $entry <: typed_parameter(name=$entry_name, $type) where {
+            $type => $config_entry_type
+        },
+
+        // migrate hass.data to entry.runtime_data
+        $body <: contains or {
+            `hass.data.setdefault($...)[entry.entry_id]`,
+            `hass.data[$_][entry.entry_id]`,
+            } as $runtime_data where {
+                $runtime_data => `$entry_name.runtime_data`
+            },
+
+        $config_entry_type_definition = `# TODO: Please add the correct type\n`,
+        $config_entry_type_definition += `type $config_entry_type = ConfigEntry`,
+        $func => `$config_entry_type_definition\n\n$func`
+    }
+}
+
+multifile {
+    bubble($domain, $config_entry_type) file($name, $body) where {
+        $file_parts = split($name, "/"),
+        $components_folder = $file_parts[-3],
+        $components_folder <: includes `components`, // with includes we allow also custom_components
+        $domain = $file_parts[-2],
+        $config_entry_type = capitalize($domain),
+        $config_entry_type += "ConfigEntry",
+        $name <: includes `__init__.py`,
+        $body <: contains and {
+            refactor_init($config_entry_type),
+            maybe refactor_functions($config_entry_type)
+        },
+    },
+    bubble($domain, $config_entry_type) file($name, $body) where {
+        $file_parts = split($name, "/"),
+        $domain = $file_parts[-2],
+        $body <: contains refactor_functions($config_entry_type)
+    }
+}
+```
\ No newline at end of file