diff --git a/buffet/commands/prop_values.h b/buffet/commands/prop_values.h
new file mode 100644
index 0000000..e03d39b
--- /dev/null
+++ b/buffet/commands/prop_values.h
@@ -0,0 +1,144 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BUFFET_COMMANDS_PROP_VALUES_H_
+#define BUFFET_COMMANDS_PROP_VALUES_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "buffet/commands/prop_constraints.h"
+#include "buffet/error.h"
+
+namespace base {
+class Value;
+class DictionaryValue;
+}  // namespace base
+
+namespace buffet {
+
+// Enumeration to indicate supported command parameter types.
+enum class ValueType {
+  Int,
+  Double,
+  String,
+  Boolean
+};
+
+// Helper methods to get the parameter type enum value for the given
+// native C++ data representation.
+// The generic GetValueType<T>() is undefined, however particular
+// type specializations return the appropriate ValueType.
+template<typename T> ValueType GetValueType();  // Undefined.
+template<> ValueType GetValueType<int>();
+template<> ValueType GetValueType<double>();
+template<> ValueType GetValueType<std::string>();
+template<> ValueType GetValueType<bool>();
+
+class ObjectSchema;
+
+class PropValue;
+class IntPropType;
+class DoublePropType;
+class StringPropType;
+class BooleanPropType;
+
+class IntValue;
+class DoubleValue;
+class StringValue;
+class BooleanValue;
+
+// The base class for parameter values.
+// Concrete value classes of various types will be derived from this base.
+class PropValue {
+ public:
+  PropValue() = default;
+  virtual ~PropValue();
+
+  // Gets the type of the value.
+  virtual ValueType GetType() const = 0;
+
+  // Type conversion methods. Used in lieu of RTTI and dynamic_cast<>.
+  virtual IntValue* GetInt() { return nullptr; }
+  virtual IntValue const* GetInt() const { return nullptr; }
+  virtual DoubleValue* GetDouble() { return nullptr; }
+  virtual DoubleValue const* GetDouble() const { return nullptr; }
+  virtual StringValue* GetString() { return nullptr; }
+  virtual StringValue const* GetString() const { return nullptr; }
+  virtual BooleanValue* GetBoolean() { return nullptr; }
+  virtual BooleanValue const* GetBoolean() const { return nullptr; }
+
+  // Makes a full copy of this value class.
+  virtual std::shared_ptr<PropValue> Clone() const = 0;
+
+  // Saves the value as a JSON object.
+  // If it fails, returns nullptr value and fills in the details for the
+  // failure in the |error| parameter.
+  virtual std::unique_ptr<base::Value> ToJson(ErrorPtr* error) const = 0;
+  // Parses a value from JSON.
+  // If it fails, it returns false and provides additional information
+  // via the |error| parameter.
+  virtual bool FromJson(const base::Value* value, ErrorPtr* error) = 0;
+};
+
+// A helper template base class for implementing simple (non-Object) value
+// classes.
+template<typename Derived, typename T>
+class TypedValueBase : public PropValue {
+ public:
+  // Overrides from PropValue base class.
+  virtual ValueType GetType() const override { return GetValueType<T>(); }
+  virtual std::shared_ptr<PropValue> Clone() const override {
+    return std::make_shared<Derived>(*static_cast<const Derived*>(this));
+  }
+
+  virtual std::unique_ptr<base::Value> ToJson(ErrorPtr* error) const override {
+    (void)error;  // unused.
+    return TypedValueToJson(value_);
+  }
+
+  virtual bool FromJson(const base::Value* value, ErrorPtr* error) override {
+    return TypedValueFromJson(value, &value_, error);
+  }
+
+  // Helper method to get and set the C++ representation of the value.
+  const T& GetValue() const { return value_; }
+  void SetValue(T value) { value_ = std::move(value); }
+
+ protected:
+  T value_{};  // The value of the parameter in C++ data representation.
+};
+
+// Value of type Integer.
+class IntValue final : public TypedValueBase<IntValue, int> {
+ public:
+  virtual IntValue* GetInt() override { return this; }
+  virtual IntValue const* GetInt() const override { return this; }
+};
+
+// Value of type Number.
+class DoubleValue final : public TypedValueBase<DoubleValue, double> {
+ public:
+  virtual DoubleValue* GetDouble() override { return this; }
+  virtual DoubleValue const* GetDouble() const override { return this; }
+};
+
+// Value of type String.
+class StringValue final : public TypedValueBase<StringValue, std::string> {
+ public:
+  virtual StringValue* GetString() override { return this; }
+  virtual StringValue const* GetString() const override { return this; }
+};
+
+// Value of type Boolean.
+class BooleanValue final : public TypedValueBase<BooleanValue, bool> {
+ public:
+  virtual BooleanValue* GetBoolean() override { return this; }
+  virtual BooleanValue const* GetBoolean() const override { return this; }
+};
+
+}  // namespace buffet
+
+#endif  // BUFFET_COMMANDS_PROP_VALUES_H_