diff --git a/agent_assembly/__init__.py b/agent_assembly/__init__.py
index b038b1a..eaf5edd 100644
--- a/agent_assembly/__init__.py
+++ b/agent_assembly/__init__.py
@@ -1,7 +1,9 @@
 """Agent Assembly Python SDK."""
 
+from agent_assembly.adapters import FrameworkAdapter, GovernanceInterceptor
 from agent_assembly.core import init_assembly
 from agent_assembly.exceptions import (
+    AdapterValidationError,
     AgentError,
     AssemblyError,
     ConfigurationError,
@@ -14,9 +16,12 @@
 __all__ = [
     "__version__",
     "init_assembly",
+    "GovernanceInterceptor",
+    "FrameworkAdapter",
     "AssemblyError",
     "AgentError",
     "PolicyError",
     "GatewayError",
     "ConfigurationError",
-]
\ No newline at end of file
+    "AdapterValidationError",
+]
diff --git a/agent_assembly/adapters/__init__.py b/agent_assembly/adapters/__init__.py
new file mode 100644
index 0000000..c16f448
--- /dev/null
+++ b/agent_assembly/adapters/__init__.py
@@ -0,0 +1,3 @@
+from agent_assembly.adapters.base import FrameworkAdapter, GovernanceInterceptor
+
+__all__ = ["GovernanceInterceptor", "FrameworkAdapter"]
diff --git a/agent_assembly/adapters/base.py b/agent_assembly/adapters/base.py
new file mode 100644
index 0000000..ca06325
--- /dev/null
+++ b/agent_assembly/adapters/base.py
@@ -0,0 +1,131 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+import importlib
+from typing import Protocol
+
+from agent_assembly.exceptions import AdapterValidationError
+
+
+class GovernanceInterceptor(Protocol):
+    """Protocol implemented by governance interceptors used by adapters."""
+
+    pass
+
+
+class FrameworkAdapter(ABC):
+    """Abstract contract implemented by every framework adapter.
+
+    Adapters should be registered through `register()` so contract validation
+    errors are raised before framework hooks are attached.
+    """
+
+    @abstractmethod
+    def get_framework_name(self) -> str:
+        """Return the canonical importable framework package name.
+
+        Error conditions:
+        - Empty or whitespace-only names trigger `AdapterValidationError`
+          during `register()`.
+        """
+
+        ...
+
+    @abstractmethod
+    def get_supported_versions(self) -> list[str]:
+        """Return supported semantic version ranges for the framework.
+
+        Error conditions:
+        - Empty lists or empty range strings trigger `AdapterValidationError`
+          during `register()`.
+        """
+
+        ...
+
+    @abstractmethod
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        """Attach framework hooks to a governance interceptor instance.
+
+        Error conditions:
+        - Framework-specific hook wiring failures should raise adapter-specific
+          exceptions for the caller to handle.
+        """
+
+        ...
+
+    @abstractmethod
+    def unregister_hooks(self) -> None:
+        """Detach all framework hooks in an idempotent way.
+
+        Error conditions:
+        - This method should avoid raising when no hooks are currently active.
+        """
+
+        ...
+
+    def validate_registration(self) -> None:
+        """Validate adapter contract values before hook registration.
+
+        Raises:
+            AdapterValidationError: If the framework name or version ranges
+                violate the base adapter contract.
+        """
+        framework_name = self.get_framework_name()
+        if not framework_name.strip():
+            raise AdapterValidationError(
+                "Adapter contract invalid: framework name must be non-empty."
+            )
+
+        supported_versions = self.get_supported_versions()
+        if not supported_versions:
+            raise AdapterValidationError(
+                "Adapter contract invalid: supported versions must not be empty."
+            )
+
+        for version_range in supported_versions:
+            if not version_range.strip():
+                raise AdapterValidationError(
+                    "Adapter contract invalid: version ranges must be non-empty strings."
+                )
+
+    def register(self, interceptor: GovernanceInterceptor) -> None:
+        """Validate contract values and then attach framework hooks.
+
+        Raises:
+            AdapterValidationError: If `validate_registration()` fails.
+        """
+        self.validate_registration()
+        self.register_hooks(interceptor)
+
+    def is_available(self) -> bool:
+        """Return True when the framework package can be imported.
+
+        Error conditions:
+        - Import failures are handled internally and return `False`.
+        """
+
+        try:
+            importlib.import_module(self.get_framework_name())
+        except ImportError:
+            return False
+
+        return True
+
+    def get_active_version(self) -> str | None:
+        """Return framework `__version__` when present, otherwise `None`.
+
+        Error conditions:
+        - Import failures and missing/non-string `__version__` values return
+          `None`.
+        """
+
+        try:
+            module = importlib.import_module(self.get_framework_name())
+        except ImportError:
+            return None
+
+        version = getattr(module, "__version__", None)
+        if isinstance(version, str):
+            return version
+
+        return None
diff --git a/agent_assembly/exceptions/__init__.py b/agent_assembly/exceptions/__init__.py
index 14886a3..b973d5d 100644
--- a/agent_assembly/exceptions/__init__.py
+++ b/agent_assembly/exceptions/__init__.py
@@ -2,6 +2,15 @@
 
 from __future__ import annotations
 
+__all__ = [
+    "AssemblyError",
+    "AgentError",
+    "PolicyError",
+    "GatewayError",
+    "ConfigurationError",
+    "AdapterValidationError",
+]
+
 
 class AssemblyError(Exception):
     """Base exception for Agent Assembly SDK errors."""
@@ -26,3 +35,8 @@ class GatewayError(AssemblyError):
 class ConfigurationError(AssemblyError):
     """Exception raised for configuration errors."""
     pass
+
+
+class AdapterValidationError(AssemblyError):
+    """Exception raised when an adapter contract is invalid."""
+    pass
diff --git a/mypy.ini b/mypy.ini
index 9d88229..70c6cf5 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -20,3 +20,6 @@ warn_unused_ignores = True
 ;no_implicit_reexport = True
 strict_equality = True
 strict_concatenate = True
+
+[mypy-agent_assembly.adapters.base]
+strict = True
diff --git a/test/unit/adapters/__init__.py b/test/unit/adapters/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/test/unit/adapters/test_base.py b/test/unit/adapters/test_base.py
new file mode 100644
index 0000000..d32ce31
--- /dev/null
+++ b/test/unit/adapters/test_base.py
@@ -0,0 +1,172 @@
+import pytest
+from types import SimpleNamespace
+
+from agent_assembly.adapters import FrameworkAdapter, GovernanceInterceptor
+from agent_assembly.exceptions import AdapterValidationError
+
+
+class IncompleteAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "math"
+
+
+def test_framework_adapter_requires_all_abstract_methods() -> None:
+    with pytest.raises(TypeError):
+        IncompleteAdapter()
+
+
+class AvailableFrameworkAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "math"
+
+    def get_supported_versions(self) -> list[str]:
+        return []
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_is_available_returns_true_when_framework_exists() -> None:
+    assert AvailableFrameworkAdapter().is_available() is True
+
+
+class MissingFrameworkAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "_agent_assembly_missing_framework_"
+
+    def get_supported_versions(self) -> list[str]:
+        return []
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_is_available_returns_false_when_framework_is_missing() -> None:
+    assert MissingFrameworkAdapter().is_available() is False
+
+
+class VersionedFrameworkAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "pytest"
+
+    def get_supported_versions(self) -> list[str]:
+        return []
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_get_active_version_returns_module_version() -> None:
+    assert VersionedFrameworkAdapter().get_active_version() is not None
+
+
+class NonVersionedFrameworkAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "math"
+
+    def get_supported_versions(self) -> list[str]:
+        return []
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_get_active_version_returns_none_without_version() -> None:
+    assert NonVersionedFrameworkAdapter().get_active_version() is None
+
+
+class InvalidRegistrationAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "   "
+
+    def get_supported_versions(self) -> list[str]:
+        return []
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_register_raises_validation_error_for_invalid_contract() -> None:
+    with pytest.raises(AdapterValidationError):
+        InvalidRegistrationAdapter().register(object())
+
+
+class ValidRegistrationAdapter(FrameworkAdapter):
+    def __init__(self) -> None:
+        self.hooks_registered = False
+
+    def get_framework_name(self) -> str:
+        return "pytest"
+
+    def get_supported_versions(self) -> list[str]:
+        return [">=8.0.0,<9.0.0"]
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        self.hooks_registered = True
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_register_calls_register_hooks_when_contract_is_valid() -> None:
+    adapter = ValidRegistrationAdapter()
+    adapter.register(object())
+    assert adapter.hooks_registered is True
+
+
+class LangChainFrameworkAdapter(FrameworkAdapter):
+    def get_framework_name(self) -> str:
+        return "langchain"
+
+    def get_supported_versions(self) -> list[str]:
+        return [">=0.1.0,<0.4.0"]
+
+    def register_hooks(self, interceptor: GovernanceInterceptor) -> None:
+        return None
+
+    def unregister_hooks(self) -> None:
+        return None
+
+
+def test_is_available_returns_true_for_langchain(monkeypatch: pytest.MonkeyPatch) -> None:
+    calls: list[str] = []
+
+    def fake_import_module(module_name: str) -> object:
+        calls.append(module_name)
+        if module_name == "langchain":
+            return SimpleNamespace(__version__="0.3.0")
+        raise ImportError
+
+    monkeypatch.setattr("agent_assembly.adapters.base.importlib.import_module", fake_import_module)
+
+    adapter = LangChainFrameworkAdapter()
+    assert adapter.is_available() is True
+    assert calls == ["langchain"]
+
+
+def test_get_active_version_returns_langchain_version(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    def fake_import_module(module_name: str) -> object:
+        if module_name == "langchain":
+            return SimpleNamespace(__version__="0.3.0")
+        raise ImportError
+
+    monkeypatch.setattr("agent_assembly.adapters.base.importlib.import_module", fake_import_module)
+
+    assert LangChainFrameworkAdapter().get_active_version() == "0.3.0"