diff --git a/src/linkml_map/cli/cli.py b/src/linkml_map/cli/cli.py
index 69081559..7c01c600 100644
--- a/src/linkml_map/cli/cli.py
+++ b/src/linkml_map/cli/cli.py
@@ -364,7 +364,7 @@ def compile(
     tr = ObjectTransformer()
     tr.source_schemaview = sv
     tr.load_transformer_specification(transformer_specification)
-    result = compiler.compile(tr.specification)
+    result = compiler.compile(tr.derived_specification)
     # dump as-is, no encoding
     dump_output(result.serialization, None, output)
 
diff --git a/src/linkml_map/compiler/compiler.py b/src/linkml_map/compiler/compiler.py
index a2630a98..7ad1c12a 100644
--- a/src/linkml_map/compiler/compiler.py
+++ b/src/linkml_map/compiler/compiler.py
@@ -64,11 +64,13 @@ class Compiler(ABC):
 
     def compile(self, specification: TransformationSpecification) -> CompiledSpecification:
         """
-        Transform source object into an instance of the target class.
+        Compile a resolved transformation specification into an alternative representation.
 
-        :param specification:
-        :return:
+        :param specification: A fully resolved specification (e.g. from
+            ``Transformer.derived_specification``).  Must not be ``None``.
+        :return: The compiled specification.
         """
+        assert specification is not None, "compile() requires a resolved specification"
         s = self._compile_header(specification)
         for chunk in self._compile_iterator(specification):
             s += chunk
diff --git a/src/linkml_map/compiler/python_compiler.py b/src/linkml_map/compiler/python_compiler.py
index 7fa57448..28f2c3a4 100644
--- a/src/linkml_map/compiler/python_compiler.py
+++ b/src/linkml_map/compiler/python_compiler.py
@@ -1,5 +1,4 @@
 from collections.abc import Iterator
-from copy import deepcopy
 from dataclasses import dataclass
 
 from jinja2 import Template
@@ -9,7 +8,6 @@
     ClassDerivation,
     TransformationSpecification,
 )
-from linkml_map.inference.inference import induce_missing_values
 
 CD_TEMPLATE = """
 {% macro gen_slot_derivation_value(sd, var) -%}
@@ -88,8 +86,6 @@ def _compile_header(self, specification: TransformationSpecification) -> str:
         return s
 
     def _compile_iterator(self, specification: TransformationSpecification) -> Iterator[str]:
-        specification = deepcopy(specification)
-        induce_missing_values(specification, self.source_schemaview)
         for cd in specification.class_derivations:
             yield from self._compiled_class_derivations_iter(cd)
 
diff --git a/src/linkml_map/transformer/transformer.py b/src/linkml_map/transformer/transformer.py
index 04cf07e5..310c8bd8 100644
--- a/src/linkml_map/transformer/transformer.py
+++ b/src/linkml_map/transformer/transformer.py
@@ -41,7 +41,21 @@ class Transformer(ABC):
     an instance of a source class, making use of a specification.
 
     This is an abstract class. Different implementations will
-    subclass this
+    subclass this.
+
+    Specification normalization has two phases:
+
+    1. **Load-time normalization** (``_normalize_spec_dict``): Structural fixes
+       applied to a raw dict before Pydantic instantiation — YAML quirk handling,
+       ``$ref`` expansion, dict-to-list conversion. Does not require a source schema.
+       All entry points (``load_transformer_specification``,
+       ``create_transformer_specification``, ``Session``, ``loaders``) go through
+       this single method.
+
+    2. **Schema-bind-time induction** (``derived_specification``): Semantic defaults
+       inferred from the source schema — ``populated_from``, ``range``, foreign-key
+       resolution. Runs lazily on first access to ``derived_specification`` and
+       requires ``source_schemaview`` to be set.
     """
 
     specification: TransformationSpecification = None
@@ -218,6 +232,16 @@ def _apply_source_schema_patches(self) -> None:
 
     @property
     def derived_specification(self) -> TransformationSpecification | None:
+        """Return the specification with schema-inferred defaults filled in.
+
+        Creates a deep copy of ``self.specification``, applies any source schema
+        patches, then calls ``induce_missing_values`` to fill in ``populated_from``,
+        ``range``, and other fields that require knowledge of the source schema.
+        The result is cached for subsequent access.
+
+        This is the second phase of normalization — see the class docstring for
+        the full two-phase pipeline.
+        """
         if self._derived_specification is None:
             if self.specification is None:
                 return None
diff --git a/tests/input/examples/personinfo_basic/output/personinfo_compiled.md b/tests/input/examples/personinfo_basic/output/personinfo_compiled.md
index d368f3a5..0a0b1d93 100644
--- a/tests/input/examples/personinfo_basic/output/personinfo_compiled.md
+++ b/tests/input/examples/personinfo_basic/output/personinfo_compiled.md
@@ -7,9 +7,9 @@
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
-| agents | | None |  persons  | . | . |
+| agents | | Agent |  persons  | . | . |
 
-### Entity `<-` None
+### Entity `<-` Entity
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
@@ -18,23 +18,23 @@
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
-| id | | None |  None  | . | . |
+| id | | None |  id  | . | . |
 | label | | None |  name  | . | . |
 | age | | None |  [expression]  | . | . |
-| primary_email | | None |  None  | . | . |
+| primary_email | | None |  primary_email  | . | . |
 | secondary_email | | None |  [expression]  | . | . |
 | gender | | None |  [expression]  | . | . |
 | driving_since | | None |  [expression]  | . | . |
 | first_known_event | | None |  [expression]  | . | . |
 | death_date | | None |  [expression]  | . | . |
-| current_address | | None |  None  | . | . |
-| has_familial_relationships | | None |  has_familial_relationships  | . | . |
+| current_address | | Address |  current_address  | . | . |
+| has_familial_relationships | | FamilialRelationship |  has_familial_relationships  | . | . |
 
-### Job `<-` None
+### Job `<-` Job
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
-| type | | None |  None  | . | . |
+| type | | None |  type  | . | . |
 | current | | None |  [expression]  | . | . |
 
 ### Address `<-` Address
@@ -42,17 +42,17 @@
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
 | address_of | | None |  [expression]  | . | . |
-| street | | None |  None  | . | . |
-| city | | None |  None  | . | . |
+| street | | None |  street  | . | . |
+| city | | None |  city  | . | . |
 
 ### FamilialRelationship `<-` FamilialRelationship
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
-| type | | None |  None  | . | . |
-| related_to | | None |  None  | . | . |
+| type | | None |  type  | . | . |
+| related_to | | Agent |  related_to  | . | . |
 
-### SequenceFeature `<-` None
+### SequenceFeature `<-` SequenceFeature
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
@@ -62,9 +62,9 @@
 
 | Target | Target Range | Source | Source Range | Info |
 | ------ | ------ | ---- | ---- | ---- |
-| id | | None |  None  | . | . |
-| creator | | None |  None  | . | . |
-| license | | None |  None  | . | . |
+| id | | None |  id  | . | . |
+| creator | | None |  creator  | . | . |
+| license | | None |  license  | . | . |
 | subject_id | | None |  [expression]  | . | . |
 | subject_name | | None |  [expression]  | . | . |
 | object_id | | None |  [expression]  | . | . |
diff --git a/tests/test_compiler/test_python_compiler.py b/tests/test_compiler/test_python_compiler.py
index e059c644..607e672a 100644
--- a/tests/test_compiler/test_python_compiler.py
+++ b/tests/test_compiler/test_python_compiler.py
@@ -8,7 +8,7 @@
 
 import tests.input.examples.personinfo_basic.model.personinfo_model as src
 from linkml_map.compiler.python_compiler import PythonCompiler
-from linkml_map.utils.loaders import load_specification
+from linkml_map.transformer.object_transformer import ObjectTransformer
 from tests import SCHEMA1, SPECIFICATION
 
 
@@ -24,8 +24,9 @@ def compiler() -> PythonCompiler:
 
 def test_compile(compiler: PythonCompiler) -> None:
     """Basic test of Python Compiler functionality."""
-    spec = load_specification(SPECIFICATION)
-    pycode = compiler.compile(spec)
+    tr = ObjectTransformer(source_schemaview=SchemaView(SCHEMA1))
+    tr.load_transformer_specification(SPECIFICATION)
+    pycode = compiler.compile(tr.derived_specification)
     # TODO: include imports so that code compiles
     print(pycode.serialization)
     mod = compile_python(pycode.serialization)
diff --git a/tests/test_compliance/test_compliance_suite.py b/tests/test_compliance/test_compliance_suite.py
index aec0a888..a9bb1811 100644
--- a/tests/test_compliance/test_compliance_suite.py
+++ b/tests/test_compliance/test_compliance_suite.py
@@ -154,15 +154,6 @@ def map_object(
     :param raises_error: if not None, the expected error to be raised during transformation
     :return: state object including transformed object plus intermediate objects
     """
-    pc = PythonCompiler(source_schemaview=source_sv)
-    python_code = pc.compile(spec)
-    logger.debug(f"Python Code: {python_code}\n\n")
-    # TODO: enable this
-    # print("Python Code (Generated)\n\n")
-    # print("```python")
-    # print(python_code.serialization)
-    # print("```\n")
-    # mod = python_code.module
     schema_mapper = SchemaMapper(source_schemaview=source_sv)
     target_schema = schema_mapper.derive_schema(spec)
     target_sv = SchemaView(yaml_dumper.dumps(target_schema))
@@ -170,6 +161,9 @@ def map_object(
         mapper = ObjectTransformer(source_schemaview=source_sv, specification=spec)
     else:
         mapper = ObjectTransformer(specification=spec)
+    pc = PythonCompiler(source_schemaview=source_sv)
+    python_code = pc.compile(mapper.derived_specification or spec)
+    logger.debug(f"Python Code: {python_code}\n\n")
     if index:
         mapper.index(source_object, target=source_root)
     if raises_error: