diff --git a/planetarium/__init__.py b/planetarium/__init__.py
index e69de29..0b019ee 100644
--- a/planetarium/__init__.py
+++ b/planetarium/__init__.py
@@ -0,0 +1,7 @@
+__all__ = ["builder", "downward", "graph", "metric", "oracle"]
+
+from . import builder
+from . import downward
+from . import graph
+from . import metric
+from . import oracle
diff --git a/planetarium/evaluate.py b/planetarium/evaluate.py
new file mode 100644
index 0000000..951acf1
--- /dev/null
+++ b/planetarium/evaluate.py
@@ -0,0 +1,64 @@
+import os
+
+from pddl.parser.problem import LenientProblemParser
+from pddl.formatter import problem_to_string
+
+from planetarium import *
+
+
+VALIDATE = os.getenv("VALIDATE", "Validate")
+
+
+def evaluate(
+    source_pddl_str: str,
+    target_pddl_str: str,
+    domain_str: str,
+    is_placeholder: bool = False,
+) -> tuple[bool, bool, bool]:
+    """Evaluate two PDDL problem descriptions for equivalence.
+
+    Args:
+        source_pddl_str (str):
+        target_pddl_str (str): The second problem PDDL string.
+        domain_str (str): The domain PDDL string.
+        is_placeholder (bool, optional): Whether or not to treat the ground truth
+            as a "placeholder" description. Defaults to False.
+
+    Returns:
+        tuple: A tuple containing the following boolean elements:
+            - parseable: Whether or not the PDDL string is parseable.
+            - solveable: Whether or not the PDDL string is solveable.
+            - equivalent: Whether or not the PDDL strings are equivalent.
+    """
+    parseable = False
+    solveable = False
+    equivalent = False
+
+    source_graph = builder.build(source_pddl_str)
+
+    try:
+        target_graph = builder.build(target_pddl_str)
+        parseable = True
+        clean_pddl_str = problem_to_string(LenientProblemParser(target_pddl_str))
+
+        solveable = downward.validate(
+            builder.build(domain_str),
+            clean_pddl_str,
+            oracle.plan_to_string(oracle.plan(target_graph)),
+            VALIDATE,
+        )
+
+        if source_graph == target_graph:
+            equivalent = True
+        elif source_graph.decompose()[0] != target_graph.decompose()[0]:
+            equivalent = False
+        else:
+            equivalent = metric.equals(
+                oracle.fully_specify(source_graph, return_reduced=True),
+                oracle.fully_specify(target_graph, return_reduced=True),
+                is_placeholder=is_placeholder,
+            )
+    except Exception:
+        pass
+
+    return parseable, solveable, equivalent
diff --git a/planetarium/oracle.py b/planetarium/oracle.py
index b4c6dcd..d269d9b 100644
--- a/planetarium/oracle.py
+++ b/planetarium/oracle.py
@@ -136,6 +136,10 @@ def join(init: ReducedSceneGraph, goal: ReducedSceneGraph) -> "ReducedProblemGra
         return problem
 
 
+class DomainNotSupportedError(Exception):
+    pass
+
+
 def _reduce_blocksworld(
     scene: graph.SceneGraph | graph.ProblemGraph,
     validate: bool = True,
@@ -347,7 +351,7 @@ def reduce(
         case "gripper":
             return _reduce_gripper(graph, validate=validate)
         case _:
-            raise ValueError(f"Domain {domain} not supported.")
+            raise DomainNotSupportedError(f"Domain {domain} not supported.")
 
 
 def _inflate_blocksworld(
@@ -535,7 +539,7 @@ def inflate(
         case "gripper":
             return _inflate_gripper(scene)
         case _:
-            raise ValueError(f"Domain {domain} not supported.")
+            raise DomainNotSupportedError(f"Domain {domain} not supported.")
 
 
 def _blocksworld_underspecified_blocks(
@@ -795,7 +799,7 @@ def fully_specify(
                 reduced_goal,
             )
         case _:
-            raise ValueError(f"Domain {domain} not supported.")
+            raise DomainNotSupportedError(f"Domain {domain} not supported.")
 
     if return_reduced:
         return ReducedProblemGraph.join(reduced_init, fully_specified_goal)
@@ -954,7 +958,7 @@ def plan(problem: graph.ProblemGraph, domain: str | None = None) -> list[Action]
         case "gripper":
             return _plan_gripper(problem)
         case _:
-            raise ValueError(f"Domain {domain} not supported.")
+            raise DomainNotSupportedError(f"Domain {domain} not supported.")
 
 
 def plan_to_string(actions: list[Action]) -> str: