microsoft--semantic-kernel/docs/decisions/0013-memory-as-plugin.md

status, contact, date, deciders, consulted, informed

status	contact	date	deciders	consulted	informed
accepted	dmytrostruk	2023-09-21	shawncal, dmytrostruk

Move all Memory-related logic to separate Plugin

Context and Problem Statement

Memory-related logic is located across different C# projects:

• SemanticKernel.Abstractions
  • IMemoryStore
  • ISemanticTextMemory
  • MemoryRecord
  • NullMemory
• SemanticKernel.Core
  • MemoryConfiguration
  • SemanticTextMemory
  • VolatileMemoryStore
• Plugins.Core
  • TextMemoryPlugin

Property ISemanticTextMemory Memory is also part of Kernel type, but kernel itself doesn't use it. This property is needed to inject Memory capabilities in Plugins. At the moment, ISemanticTextMemory interface is main dependency of TextMemoryPlugin, and in some examples TextMemoryPlugin is initialized as new TextMemoryPlugin(kernel.Memory).

While this approach works for Memory, there is no way how to inject MathPlugin into other Plugin at the moment. Following the same approach and adding Math property to Kernel type is not scalable solution, as it's not possible to define separate properties for each available Plugin.

Decision Drivers

1. Memory should not be a property of Kernel type if it's not used by the kernel.
2. Memory should be treated in the same way as other plugins or services, that may be required by specific Plugins.
3. There should be a way how to register Memory capability with attached Vector DB and inject that capability in Plugins that require it.

Decision Outcome

Move all Memory-related logic to separate project called Plugins.Memory. This will allow to simplify Kernel logic and use Memory in places where it's needed (other Plugins).

High-level tasks:

1. Move Memory-related code to separate project.
2. Implement a way how to inject Memory in Plugins that require it.
3. Remove Memory property from Kernel type.