diff --git a/kiwi_scp/_constants.py b/kiwi_scp/_constants.py
index cd12c09..62a46f9 100644
--- a/kiwi_scp/_constants.py
+++ b/kiwi_scp/_constants.py
@@ -1,6 +1,18 @@
 # system
 import os
 
+#############
+# REGEX PARTS
+
+# regex part for a number with no leading zeroes
+_RE_NUMBER: str = r"[0-9]|[1-9][0-9]*"
+
+# regex for a semantic version string
+RE_SEMVER = rf"^{_RE_NUMBER}(?:\.{_RE_NUMBER}(?:\.{_RE_NUMBER})?)?$"
+
+# regex for a lowercase variable name
+RE_VARNAME = r"^[A-Za-z](?:[A-Za-z0-9_-]*[A-Za-z0-9])$"
+
 #############
 # ENVIRONMENT
 
diff --git a/kiwi_scp/config.py b/kiwi_scp/config.py
index b276fa6..ea5ba12 100644
--- a/kiwi_scp/config.py
+++ b/kiwi_scp/config.py
@@ -1,48 +1,67 @@
-import re
+from ipaddress import IPv4Network
+from pathlib import Path
 from typing import Optional, Dict, List
 
 import pydantic
 
+from ._constants import RE_SEMVER, RE_VARNAME
+
 
 class _Storage(pydantic.BaseModel):
     """a storage subsection"""
 
-    directory: str
+    directory: Path
 
 
 class _Project(pydantic.BaseModel):
     """a project subsection"""
 
-    name: str
+    name: pydantic.constr(
+        regex=RE_VARNAME
+    )
     enabled: bool = True
-    storage: Optional[_Storage]
+    override_storage: Optional[_Storage]
 
     @pydantic.root_validator(pre=True)
     @classmethod
-    def check_grammar(cls, values):
-        if isinstance(values, dict):
-            if "name" in values:
-                return values
+    def unify_project(cls, values):
+        """parse different project notations"""
 
-            elif len(values) == 1:
-                name, enabled = list(values.items())[0]
-                return {"name": name, "enabled": True if enabled is None else enabled}
+        if "name" in values:
+            # default format
+            return values
 
-        elif isinstance(values, str):
-            return {"name": values}
+        elif len(values) == 1:
+            # short format:
+            # - <name>: <enabled>
+
+            name, enabled = list(values.items())[0]
+            return {
+                "name": name,
+                "enabled": True if enabled is None else enabled
+            }
+
+        else:
+            # undefined format
+            raise ValueError
 
 
 class _Network(pydantic.BaseModel):
     """a network subsection"""
 
-    name: str
-    cidr: str
+    name: pydantic.constr(
+        to_lower=True,
+        regex=RE_VARNAME
+    )
+    cidr: IPv4Network
 
 
 class Config(pydantic.BaseModel):
     """represents a kiwi.yml"""
 
-    version: str
+    version: pydantic.constr(
+        regex=RE_SEMVER
+    )
     shells: Optional[List[str]]
     environment: Optional[Dict[str, Optional[str]]]
 
@@ -50,30 +69,51 @@ class Config(pydantic.BaseModel):
     storage: _Storage
     network: _Network
 
-    @pydantic.validator("version")
-    @classmethod
-    def check_version(cls, value: str) -> str:
-        if not re.match(r"^[0-9]+(\.[0-9]+(\.[0-9]+)?)?$", value):
-            raise ValueError
-
-        return value
-
     @pydantic.validator("environment", pre=True)
     @classmethod
-    def unify_env(cls, value) -> Optional[Dict[str, Optional[str]]]:
-        if isinstance(value, dict):
+    def unify_environment(cls, value) -> Optional[Dict[str, Optional[str]]]:
+        """parse different environment notations"""
+
+        def parse_str(var_val: str) -> (str, Optional[str]):
+            """parse a "<variable>=<value>" string"""
+
+            idx = var_val.find("=")
+            if idx == -1:
+                # don't split, just define the variable
+                return var_val, None
+            else:
+                # split string, set variable to value
+                return var_val[:idx], var_val[idx + 1:]
+
+        if value is None:
+            # empty environment
+            return None
+
+        elif isinstance(value, dict):
+            # native dict format
             return value
+
         elif isinstance(value, list):
+            # list format (multiple strings)
+
             result: Dict[str, Optional[str]] = {}
             for item in value:
-                idx = item.find("=")
-                if idx == -1:
-                    key, value = item, None
-                else:
-                    key, value = item[:idx], item[idx + 1:]
-
+                key, value = parse_str(item)
                 result[key] = value
 
             return result
+
+        elif isinstance(value, str):
+            # string format (single variable):
+            # "<var>=<value>"
+
+            key, value = parse_str(value)
+            return {key: value}
+
+        elif isinstance(value, int):
+            # integer format (just define single oddly named variable)
+            return {str(value): None}
+
         else:
-            return None
+            # undefined format
+            raise ValueError
diff --git a/kiwi_scp/data/etc/kiwi_default.yml b/kiwi_scp/data/etc/kiwi_default.yml
index 44766a7..bb8335f 100644
--- a/kiwi_scp/data/etc/kiwi_default.yml
+++ b/kiwi_scp/data/etc/kiwi_default.yml
@@ -4,7 +4,7 @@ shells:
 projects:
   - name: admin
     enabled: true
-  - test:
+  - Test:
   - test2: false
 storage:
   directory: /var/local/kiwi