MGP vs MCP

This document explains the relationship between MGP and MCP.

The Short Version

• MCP is for tools and resources
• MGP is for governed persistent memory

They are peer protocols, not parent and child.

Side-By-Side Comparison

Dimension	MCP	MGP
Focus	Tool & resource connectivity	Governed persistent memory
Protocol surface	Tool invocation, prompt templates, resource discovery	Memory CRUD, policy context, audit, lifecycle, conflict resolution
Data model	Tools, prompts, resources	Memory objects, candidates, recall intents, audit events
Governance	Not in scope	Policy context on every request, access control hooks
Lifecycle	Not in scope	Expire, revoke, delete, purge — each with distinct semantics
Audit	Not in scope	Built-in audit trail and lineage tracking
Retention	Not in scope	TTL, retention policies, expiration enforcement
Architecture level	Runtime ↔ external capabilities	Runtime ↔ memory backends
Relationship	Peer protocol	Peer protocol

Architectural Relationship

MCP and MGP sit at the same architectural level.

graph TD
  Runtime["Runtime"]
  MCP["MCP Client"]
  MGP["MGP Client"]
  Tools["Tool / Resource Servers"]
  Memory["MGP Gateway / Memory Backends"]

  Runtime --> MCP
  Runtime --> MGP
  MCP --> Tools
  MGP --> Memory

What MCP Governs

MCP standardizes how runtimes connect to:

• tools
• prompts
• resources

Its strength is interoperability around external capabilities that the model or runtime may call during execution.

What MGP Governs

MGP standardizes how runtimes interact with:

• memory objects
• memory lifecycle
• policy context
• retention and revocation
• conflicts
• audit and lineage

Its strength is governed memory interoperability.

Practical Guidance

Use MCP when the runtime needs to:

• call tools
• read resources
• interact with external capabilities

Use MGP when the runtime needs to:

• recall memory
• write persistent memory
• apply memory governance
• honor return modes, redaction behavior, and audit behavior

Can a Runtime Use Both?

Yes. In fact, that is the expected long-term shape for advanced agent runtimes.

Example:

• use MCP to call a calendar tool
• use MGP to remember the user's long-term scheduling preferences

What MGP Is Not

MGP is not:

• an MCP extension
• an MCP transport profile
• a wrapper around MCP tools

What MCP Is Not

MCP is not:

• a memory governance protocol
• a replacement for lifecycle, retention, or audit semantics

One-Line Heuristic

Use MCP for action, use MGP for memory.