sap-support-mcp

An MCP server over Streamable HTTP that exposes two SAP help-desk operations to an AI agent:

Tool	What it does
sap_reset_password	Sets a user's password to a generated temporary value via BAPI_USER_CHANGE. The password is stored as initial, so SAP forces the user to choose a new one at next logon.
sap_unlock_users	Clears the administrator lock and resets the failed-logon counter for 1–25 users via BAPI_USER_UNLOCK.

The two are deliberately separate, because SAP treats them separately: unlocking does not change a password, and resetting a password does not clear a lock. A user who is locked and has forgotten their password needs both. sap_reset_password detects this case and says so in its response.

How it talks to SAP

Calls go over plain HTTP to the ABAP system's SOAP RFC service (/sap/bc/soap/rfc) with basic authentication — no SAP NetWeaver RFC SDK, no native binaries, so the server runs anywhere Node does.

MCP client ──Streamable HTTP──▶ sap-support-mcp ──SOAP/HTTPS──▶ /sap/bc/soap/rfc ──▶ BAPI_USER_*

Three function modules are used: BAPI_USER_GET_DETAIL (existence + lock state), BAPI_USER_CHANGE (password), BAPI_USER_UNLOCK (locks).

Each SOAP RFC call is its own stateless session, so a follow-up BAPI_TRANSACTION_COMMIT would land in a different LUW and do nothing. That is fine here: the BAPI_USER_* modules commit internally. Do not extend this server with BAPIs that require an explicit commit without first moving to a stateful transport.

Setup

npm install
cp .env.example .env

Generate the bearer token clients will use:

node -e "console.log(require('crypto').randomBytes(32).toString('base64url'))"

Fill in .env, then:

npm run dev

For production:

npm run build && npm start

SAP-side prerequisites

1. The SOAP RFC service must be active in SICF at /sap/bc/soap/rfc.
2. Create a dedicated technical user (type Communications) for SAP_USER. It needs:
   • S_RFC — activity 16, function groups SUSR and SU_USER (or the specific modules BAPI_USER_GET_DETAIL, BAPI_USER_CHANGE, BAPI_USER_UNLOCK).
   • S_USER_GRP — ACTVT 02 (change) and 05 (lock/unlock), with CLASS restricted to the user groups the help desk is allowed to serve. This is the strongest control available — the allow/deny lists in this server are defence in depth on top of it, not a replacement for it.
3. Do not give the technical user S_USER_GRP over the SUPER group.

Configuration

Every setting is an environment variable; see .env.example for the full list with comments. The ones that matter most:

Variable	Purpose
MCP_AUTH_TOKEN	Bearer token required on every MCP request. No unauthenticated mode exists. Minimum 16 characters.
SAP_BASE_URL, SAP_CLIENT, SAP_USER, SAP_PASSWORD	The target system and the technical user.
USER_ALLOW_LIST	If set, only matching users can be targeted. Supports *, e.g. SUPPORT_*,BUSINESS_*.
USER_DENY_LIST	Merged on top of the built-in deny list. Deny always beats allow.
AUDIT_LOG_FILE	JSONL audit trail. Defaults to audit/sap-support-mcp.audit.jsonl.
SAP_REJECT_UNAUTHORIZED	Leave true. Set false only for a sandbox with a self-signed certificate.

Guardrails

Bearer auth. Every request to MCP_PATH needs Authorization: Bearer <token>, compared with a timing-safe equality check. /healthz is the only unauthenticated route and reveals nothing about SAP.

Allow / deny lists. SAP*, DDIC, SAPCPIC, EARLYWATCH, TMSADM, SAPSUPPORT, ADS_AGENT and ADSUSER are denied unconditionally — adding * to the allow list cannot expose them. Patterns are anchored, so SUPPORT_* does not match XSUPPORT_1. A denied user is rejected before any call reaches SAP.

Dry run. Both tools take dryRun: true, which checks the policy and confirms the user exists and reports its current lock state, without changing anything.

Audit trail. Append-only JSONL. Each operation writes an attempt record before touching SAP and a terminal record (success / failed / denied / dry_run) afterwards, sharing one correlationId, so a crash mid-call still leaves evidence:

{"ts":"2026-07-31T08:18:49.261Z","correlationId":"ed66d93a…","operation":"unlock_user","outcome":"attempt","targetUser":"JDOE","sapClient":"100","reason":"INC-SMOKE-1","sessionId":"9b85a10a…","clientIp":"127.0.0.1"}

Every tool call requires a reason (ticket number or justification) which is recorded. Generated passwords are never written to the audit trail — AuditLog has no field that could carry one, and a test asserts the password does not appear in the file.

Connecting a client

{
  "mcpServers": {
    "sap-support": {
      "type": "http",
      "url": "http://127.0.0.1:3000/mcp",
      "headers": { "Authorization": "Bearer YOUR_TOKEN_HERE" }
    }
  }
}

Sessions are stateful: the server issues an Mcp-Session-Id on initialize, and each session gets its own McpServer instance so caller identity stays isolated in the audit trail.

Security notes worth reading before you deploy this

• The temporary password passes through the model's context. sap_reset_password returns it in the tool result, so it is visible to the LLM and to whatever transcript store sits behind it. That is inherent to handing a password back through MCP. If your threat model cannot accept it, change resetPassword.ts to deliver the password out of band (email the user, push to a vault) and return only a confirmation.
• HOST defaults to 127.0.0.1. Binding to 0.0.0.0 puts SAP password resets on your network; put it behind TLS and a reverse proxy if you do.
• Everything the caller supplies is XML-escaped before it enters the SOAP envelope, and usernames are additionally validated against SAP's character rules, so a crafted username cannot inject extra RFC parameters.
• The deny list protects against a confused agent, not a hostile one holding the bearer token. S_USER_GRP on the SAP side is the real boundary.

Tests

npm test

43 tests, no SAP system required. test/mockSap.ts is a stand-in for /sap/bc/soap/rfc that reproduces SAP's real response shapes — including message class 01/124 for an unknown user, HTTP 401 for bad credentials, SOAP faults, and the fact that BAPI_USER_UNLOCK clears an administrator lock but not a CUA global lock. The end-to-end tests drive the real Express app through a real MCP client over Streamable HTTP.

Layout

src/
  index.ts              entry point: config, wiring, graceful shutdown
  config.ts             env schema + built-in deny list
  http/
    server.ts           Express app, Streamable HTTP transport, session registry
    auth.ts             bearer token middleware
  mcp/
    server.ts           McpServer construction + instructions
    tools/
      resetPassword.ts  sap_reset_password
      unlockUsers.ts    sap_unlock_users
  sap/
    soap.ts             SOAP envelope building, XML escaping, fault handling
    userService.ts      the three BAPIs + RETURN-table interpretation
  security/
    policy.ts           allow/deny evaluation
    audit.ts            append-only JSONL audit trail
  util/
    password.ts         temporary password generation