diff --git a/gen/gen.py b/gen/gen.py
index 50c9c9d..9ea59ee 100644
--- a/gen/gen.py
+++ b/gen/gen.py
@@ -1,3 +1,9 @@
+"""
+Helper script to generate AST nodes for Midas and Python.
+
+Takes in simple templates and generates full dataclasses and a visitor interface
+"""
+
 import re
 from pathlib import Path
 
diff --git a/midas/ast/location.py b/midas/ast/location.py
index 47fe360..4d1d7bf 100644
--- a/midas/ast/location.py
+++ b/midas/ast/location.py
@@ -13,6 +13,8 @@ class HasLocation(Protocol):
 
 @dataclass(frozen=True, kw_only=True)
 class Location:
+    """Information about the location of an AST node"""
+
     lineno: int
     col_offset: int
     end_lineno: Optional[int]
@@ -29,6 +31,16 @@ class Location:
 
     @staticmethod
     def span(start: Location, end: Location) -> Location:
+        """Create a new location spanning from one location to another
+
+        Args:
+            start (Location): the starting location
+            end (Location): the end location
+
+        Returns:
+            Location: a new location spanning from the start of `start`
+                to the end of `end`
+        """
         return Location(
             lineno=start.lineno,
             col_offset=start.col_offset,
diff --git a/midas/checker/builtins.py b/midas/checker/builtins.py
index be6a781..427d414 100644
--- a/midas/checker/builtins.py
+++ b/midas/checker/builtins.py
@@ -14,12 +14,15 @@ if TYPE_CHECKING:
     from midas.checker.registry import TypesRegistry
 
 
-# Hard-coded subtype relationships between builtin types
-# Circular dependencies and diamond inheritance MUST be avoided
 BUILTIN_SUBTYPES: dict[str, set[str]] = {
     "object": {"float", "list", "dict", "str", "bytes", "tuple"},
     "float": {"int"},
 }
+"""
+Hard-coded subtype relationships between builtin types
+
+Circular dependencies and diamond inheritance MUST be avoided
+"""
 
 
 def define_builtins(reg: TypesRegistry):
diff --git a/midas/checker/checker.py b/midas/checker/checker.py
index c64a282..a305ad1 100644
--- a/midas/checker/checker.py
+++ b/midas/checker/checker.py
@@ -10,6 +10,11 @@ from midas.utils import TypedAST
 
 
 class TypeChecker:
+    """Type checking dispatcher
+
+    Contains a typer for Midas and one for Python, as well as the types registry
+    """
+
     def __init__(self):
         self.types: TypesRegistry = TypesRegistry()
         self.reporter: Reporter = Reporter()
diff --git a/midas/checker/diagnostic.py b/midas/checker/diagnostic.py
index 233dd74..04a5ce2 100644
--- a/midas/checker/diagnostic.py
+++ b/midas/checker/diagnostic.py
@@ -14,6 +14,15 @@ class DiagnosticType(StrEnum):
 
 @dataclass(frozen=True)
 class Diagnostic:
+    """Information about a diagnostic (warning, errors, etc.)
+
+    Holds a location, a diagnostic type and a message.
+    Optionally bound to a file path
+
+    Returns:
+        _type_: _description_
+    """
+
     file_path: Optional[str]
     location: Location
     type: DiagnosticType
@@ -21,6 +30,18 @@ class Diagnostic:
 
     @property
     def location_str(self) -> str:
+        """The diagnostic type and location as a human readable string
+
+        The location is formatted as "<Type> in <file> from L<start_line>:<start_col> to <end_line>:<end_col>",
+        for example: "Error in /home/user/Desktop/script.py from L12:5 to L12:8"
+
+        If the file is `None`, the "in ..." section is excluded from the result.<br>
+        If the location's end is not specified, the formulation "at L<start_line>:<start_col>" is used.
+
+        Returns:
+            str: _description_
+        """
+
         start_loc: str = f"L{self.location.lineno}:{self.location.col_offset+1}"
         end_loc: Optional[str] = ""
         if (