diff --git a/icepyx/core/APIformatting.py b/icepyx/core/APIformatting.py
index 6d6c6edc6..a70b66e0a 100644
--- a/icepyx/core/APIformatting.py
+++ b/icepyx/core/APIformatting.py
@@ -3,6 +3,7 @@
 import datetime as dt
 from typing import Any, Generic, Literal, Optional, TypeVar, Union, overload
 
+from icepyx.core.exceptions import ExhaustiveTypeGuardException, TypeGuardException
 from icepyx.core.types import (
     CMRParams,
     EGIParamsSubset,
@@ -326,7 +327,7 @@ def poss_keys(self) -> dict[str, list[str]]:
                 ],
             }
         else:
-            raise RuntimeError("Programmer error!")
+            raise ExhaustiveTypeGuardException
 
     # @property
     # def wanted_keys(self):
@@ -362,7 +363,7 @@ def check_req_values(self) -> bool:
         ), "You cannot call this function for your parameter type"
 
         if not self._reqtype:
-            raise RuntimeError("Programmer error!")
+            raise TypeGuardException
 
         reqkeys = self.poss_keys[self._reqtype]
 
@@ -427,7 +428,7 @@ def build_params(self, **kwargs) -> None:
 
         if self.partype == "required":
             if not self._reqtype:
-                raise RuntimeError("Programmer error!")
+                raise TypeGuardException
 
             if self.check_req_values() and kwargs == {}:
                 pass
@@ -496,7 +497,7 @@ def build_params(self, **kwargs) -> None:
                             k = "Boundingshape"
 
                     if not k:
-                        raise RuntimeError("Programmer error!")
+                        raise TypeGuardException
 
                     self._fmted_keys.update({k: kwargs["spatial_extent"]})
 
diff --git a/icepyx/core/exceptions.py b/icepyx/core/exceptions.py
index 94bbea768..085fed8c9 100644
--- a/icepyx/core/exceptions.py
+++ b/icepyx/core/exceptions.py
@@ -1,3 +1,10 @@
+ISSUE_REPORTING_INSTRUCTIONS = (
+    "If you are a user seeing this message, the developers of this software have made a"
+    " mistake! Please report the full error traceback in the icepyx GitHub repository:"
+    " <https://github.com/icesat2py/icepyx/issues/new>"
+)
+
+
 class DeprecationError(Exception):
     """
     Class raised for use of functionality that is no longer supported by icepyx.
@@ -24,3 +31,25 @@ def __init__(
 
     def __str__(self):
         return f"{self.msgtxt}: {self.errmsg}"
+
+
+class TypeGuardException(Exception):
+    """
+    Should never be raised at runtime.
+
+    Used in cases where a runtime check is not desired, but we want to add a "type guard"
+    (https://github.com/microsoft/pyright/blob/main/docs/type-concepts-advanced.md#type-guards)
+    to give the type checker more information.
+    """
+
+    def __str__(self):
+        return ISSUE_REPORTING_INSTRUCTIONS
+
+
+class ExhaustiveTypeGuardException(TypeGuardException):
+    """
+    Should never be raised at runtime.
+
+    Used exclusively in cases where the typechecker needs a typeguard to tell it that a
+    check is exhaustive.
+    """