ai-enabled-hr-talent-automation

MCP Architecture

Title: MCP Architecture

Version: 1.0

Owner: [TENANT_CONFIGURATION_REQUIRED — Integration Architecture]

Status: Draft

Last reviewed: 2026-09-07

Next review: [TENANT_CONFIGURATION_REQUIRED]

Reviewers: Architecture, Security

Purpose and scope

Details the MCP (Model Context Protocol) server topology implementing ADR-004: one isolated, authenticated MCP server per external system domain.

Topology

flowchart TB
    subgraph AgentPlane [Agent Plane]
        TG[Tool Gateway]
    end
    subgraph MCPServers [MCP Servers - each isolated, independently deployed]
        M1[mcp-calendar]
        M2[mcp-email]
        M3[mcp-hrms]
        M4[mcp-esignature]
        M5[mcp-document-management]
        M6[mcp-background-verification]
        M7[mcp-payroll]
        M8[mcp-it-provisioning]
    end
    subgraph External [External Systems]
        E1[Calendar Provider]
        E2[Email Provider]
        E3[HRMS]
        E4[E-signature Vendor]
        E5[Document Management System]
        E6[Background Verification Vendor]
        E7[Payroll System]
        E8[IT Provisioning System]
    end

    TG --> M1 --> E1
    TG --> M2 --> E2
    TG --> M3 --> E3
    TG --> M4 --> E4
    TG --> M5 --> E5
    TG --> M6 --> E6
    TG --> M7 --> E7
    TG --> M8 --> E8

Server catalog

MCP server	Domain	Tool tiers offered	Vendor (configurable)
mcp-calendar	Interview scheduling	Read-only (availability), propose-only (draft invite)	[TENANT_CONFIGURATION_REQUIRED — M365/Google Workspace]
mcp-email	Notifications	Propose-only (draft), approval-required write (send) for candidate-facing sensitive emails	[TENANT_CONFIGURATION_REQUIRED]
mcp-hrms	Org reference data, employee creation	Read-only (reference data), approval-required write (employee record creation)	[TENANT_CONFIGURATION_REQUIRED]
mcp-esignature	Offer execution	Approval-required write (send for signature)	[TENANT_CONFIGURATION_REQUIRED]
mcp-document-management	External DMS (if used)	Read-only, propose-only	[TENANT_CONFIGURATION_REQUIRED]
mcp-background-verification	BGV initiation/results	Approval-required write (initiate check), read-only (results)	[TENANT_CONFIGURATION_REQUIRED]
mcp-payroll	New-hire feed	Approval-required write	[TENANT_CONFIGURATION_REQUIRED]
mcp-it-provisioning	Account/access requests	Approval-required write	[TENANT_CONFIGURATION_REQUIRED]

Isolation properties

Each server: its own deployment unit, its own credentials (scoped to only that external system), its own network egress allowlist, independent versioning/rollback, and independent circuit breaker. A compromise of one MCP server does not grant access to another (see ADR-004).

Cross-references

mcp-security-and-authorization.md · mcp-tool-governance.md · integration-adapter-catalog.md · mcp/servers/README.md · mcp/tool-schemas/hr-tools.schema.json

Change control

Version	Date	Author	Change
1.0	2026-09-07	Documentation package generation	Initial creation

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