Architecture

A detailed look at the architectural components and interactions within the MCP-I framework

Overview


Built on the Model Context Protocol

MCP-I is an extension of the Model Context Protocol, providing delegated identity to AI agents, enforced through verifiable credentials and a tamper-evident audit chain. This allows agents to act on behalf of users while still operating under secure, accountable identity boundaries. It retains full interoperability with existing MCP-compatible agents and services, while enabling a higher trust model for agent actions.


Core Services

MCP-I is composed of modular components that align with decentralized identity and secure delegation:

  • DID Service – Issues and resolves Decentralized Identifiers (DIDs)
  • Credential Service – Issues Verifiable Credentials (e.g. delegation)
  • Delegation Service – Verifies and chains authority credentials
  • Edge Verifier – Enforces identity + delegation checks before request passes to backend
  • Audit Service – Tracks identity, credential, and delegation events
  • Core Service – Orchestrates events, registry, crypto utilities

Component Roles

Core Components

  • Principal/User: The entity delegating authority to the agent
  • Agent: Software component acting on behalf of the principal
  • Service/Resource: System providing resources or tools via MCP
  • Edge Proxy/Verifier: Validates agent identities and delegations

Infrastructure Components

  • DID Resolver: Resolves decentralized identifiers to DID documents
  • Revocation Service: Checks credential revocation status
  • Reputation Service: Provides agent reputation information

Integration with Core MCP

MCP-I extends the Model Context Protocol with identity and delegation capabilities while maintaining full compatibility:

  • Transport Layer: Reuses MCP transports (HTTP/SSE, stdio)
  • Message Format: Extends MCP message format with identity headers
  • Tools & Resources: Compatible with existing tool and resource definitions
  • Client-Server Model: Maintains the same client-server architecture

Data Flow in MCP-I

Registration Flow

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Request Verification Flow (Level 1)

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Direct Service Authentication (Level 2+)

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Trust Boundaries

MCP-I establishes clear trust boundaries between components:

Trust Model

ComponentTrustsVerification Responsibility
AgentNoneProves identity and delegation
Edge ProxyDID infrastructureVerifies agent credentials
Service (L1)Edge ProxyAccepts proxy assertions
Service (L2+)DID infrastructureVerifies credentials directly
UserIdentity/credential providerIssues valid delegations

Security Assumptions

  • Agents are untrusted until proven otherwise through cryptographic verification
  • DID resolution infrastructure is reliable and trustworthy
  • Private keys are properly secured by their respective owners
  • Edge Proxy is a trusted component for Level 1 implementations

Orchestration & Extensibility

All services can be deployed independently or managed centrally. The Core Service:

  • Dynamically activates and deactivates services needed for identity, credential issuance, and delegation pipelines
  • Maintains a live directory of all available MCP-I service endpoints and capabilities
  • Hosts event bus for system-wide communication

You can plug in capabilities such as:

  • DID Methods — Choose how your agents and users are identified. did:key offers simplicity, did:web supports domain-based trust, and did:ion anchors identifiers to public blockchains.
  • Credential Schemas — Tailor what your credentials assert: permissions, roles, identity metadata, or custom business rules.
  • Revocation Strategies — Use privacy-preserving Bitstring Status Lists or integrate your own backend revocation system.
  • SDKs & Runtimes — Bring identity-native behaviors into frontends, mobile agents, or cloud services with supported SDKs like KYA-OS.

Next Steps