Salesforce SAP MCP Integration

Claude connects directly to Salesforce via a custom MCP Server, invoking Apex to fetch live SAP inventory data. No middleware. No Flow. Direct agent-to-backend integration.

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Business Problem

AI agents need a secure, structured way to call enterprise backend systems — not screen scraping, not unstructured API calls. MCP (Model Context Protocol) solves this by exposing typed, governed tools that an LLM can call directly.

This project proves Claude can securely query live SAP inventory data through Salesforce, using Apex as the typed execution layer.

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Architecture

How It Works

1. Claude calls the registered MCP tool SAPInventoryService with a SKU
2. Request authenticated via OAuth 2.0 JWT Bearer flow through the External Client App
3. Salesforce MCP Server routes the call to the Apex InvocableMethod
4. Apex makes an HTTP callout via Named Credential to the SAP endpoint
5. Response parsed and returned as typed output
6. Claude composes a natural language answer from the structured data

Live Verified Response

Field	Value
SKU	IPX-200
Product	Industrial Pump X200
Available Qty	850 units
Status	In Stock
Warehouse	Mumbai WH-1
Lead Time	3 days

Components

Component	Type	Purpose
SalesforceSAPMCP	MCP Server Definition	Exposes Apex as MCP tool
Claude_Connect_Salesforce_MCP	External Client App	OAuth/JWT auth for Claude
SAPInventoryService	Apex Class (Invocable)	Calls SAP, returns typed result
SAPInventoryServiceTest	Apex Test Class	Test coverage
SAP_Mock_API	Named Credential	Secure SAP endpoint URL
SAP_Mock_External	External Credential	Auth configuration
SAP_Agent_Access	Permission Set	Apex + object access

Security — JWT Bearer Flow

Step	What Happens
1	Claude authenticates using a signed JWT, not username/password
2	Salesforce validates the JWT signature against the registered certificate
3	Salesforce issues a session token scoped to the MCP server's permitted tools
4	No long-lived credentials exposed — every session is token-based and short-lived

Same auth pattern enterprises use for server-to-server integrations, applied here to agent-to-backend communication.

Apex Implementation

@InvocableMethod(
    label='Get SAP Inventory'
    description='Fetches live inventory data from SAP for a given product SKU'
)
global static List<InventoryResult> getInventory(List<InventoryRequest> requests) {
    // Calls SAP_Mock_API named credential
    // Returns typed InventoryResult: productName, availableQty, 
    // warehouse, leadTimeDays, status
}

Typed request/response wrapper classes mean the MCP tool schema is strongly typed — Claude knows exactly what input is required and what shape the response takes.

Problems Faced & How They Were Solved

Problem	Root Cause	Fix
External Credential access error on Apex callout	MCP server's execution user lacked the External Credential principal mapping	Added principal mapping to SAP_Agent_Access permission set, assigned to integration user
MCP tool not appearing for Claude	Apex method not registered in McpServerDefinition metadata	Added tool registration block mapping SAPInventoryService as a callable tool

Prerequisites

Requirement	Detail
Salesforce org	MCP Server support enabled
External Client App	JWT Bearer Flow configured
Salesforce CLI	npm install -g @salesforce/cli

Deployment

sf org login web
sf project deploy start --manifest package.xml
sf org assign permset --name SAP_Agent_Access
sf org assign permset --name SAP_Mock_API_Access

Admin Configuration

Step	Action
1	External Client App — enable "Issue JWT-based access tokens" under OAuth settings
2	Upload certificate — generate self-signed cert, upload public key to External Client App
3	Permission Set Mapping — map External Credential principal to integration user's permission set
4	MCP Server Definition — verify SAPInventoryService tool is listed and active
5	Connect from claude.ai — add Salesforce MCP connector using the org's My Domain URL, not api.salesforce.com

Demo

Production Considerations

Area	Current State	Production Fix
SAP endpoint	Mock via Beeceptor	Update Named Credential URL to real S/4HANA endpoint — no Apex changes needed
Error handling	Apex returns success:false with errorMessage on failure	Already production-ready — Claude surfaces errors gracefully
Rate limiting	Single SKU per call	Add governor limit checks for bulk SKU lookups

Key Insight

The agent is a trigger, not an executor. Claude extracts the SKU from natural language and calls a typed Apex method — validation rules, sharing rules, and business logic all still apply. MCP is the contract layer that makes this connection type-safe and secure.

Tech Stack

Layer	Technology
AI Connector	Claude (claude.ai MCP connector)
Auth	OAuth 2.0 JWT Bearer Flow
Backend Logic	Apex (@InvocableMethod)
Credential Management	Named Credentials + External Credentials
MCP Layer	Salesforce MCP Server Definition