Happy Platform MCP v5.1 Installation

Overview

Install Happy Platform MCP v5.1, register one or more ServiceNow instances, and connect an MCP host without exposing authentication material to the model, MCP messages, logs, shell history, or client JSON. Keep the MCP-first policy: use live SN-* tools for ServiceNow work after local setup; use raw REST only when no MCP tool can perform the operation and the caller already has a locally managed credential helper.

Prerequisites

• Node.js >= 20
• Happy Platform MCP 5.1.0 or a compatible later 5.x release
• A local interactive terminal for masked prompts
• An OS keychain available to the current user
• An MCP-capable client and appropriate ServiceNow access

Procedure

Step 1: Install the Server

Use npm for a normal installation:

npm install -g happy-platform-mcp@5.1.0
happy-platform-mcp --version

An MCP host can instead launch the package with npx -y happy-platform-mcp@5.1.0. Do not add authentication material to its arguments or environment block.

Step 2: Choose an Authentication Mode

Run happy-platform-mcp instance add locally. It gathers required values through interactive masked prompts and puts credential material in the OS keychain. The model must never ask the user to paste, echo, log, document, or send that material in an MCP call.

Mode	Choose when	Local setup behavior
Basic	A named integration user is required	Prompts locally for the user identity and its credential
OAuth client_credentials	A non-interactive service integration is required	Prompts locally for client metadata and the client credential
OAuth password	A legacy resource-owner flow is explicitly required	Prompts locally for user and client credentials; prefer a stronger flow when possible
Public authorization_code with PKCE	Per-user browser sign-in is available	Direct zero-static-secret path; the browser flow stores refresh state in the OS keychain

Use the local CLI lifecycle:

happy-platform-mcp instance add
happy-platform-mcp instance list
happy-platform-mcp instance test dev
happy-platform-mcp instance update dev
happy-platform-mcp instance remove dev
happy-platform-mcp instance migrate

instance update changes metadata only. Authentication changes require remove then re-add. Use happy-platform-mcp instance credential set dev only to rotate an already-registered instance or complete an existing metadata-only registration; it cannot bootstrap a new instance name.

Step 3: Understand Registry Storage

The default version 1 user registry is ~/.config/happy-platform-mcp/instances.json. It contains non-secret metadata and canonical credentialRef values only. Credentials remain in the OS keychain. Do not manually add plaintext values to the registry.

HAPPY_CONFIG_PATH overrides the registry location and supports absolute paths, relative paths, and ~. Set it before running the CLI and provide the same value to the MCP host. This is safe host configuration because it identifies metadata, not a credential.

{
  "mcpServers": {
    "happy-platform-mcp": {
      "command": "npx",
      "args": ["-y", "happy-platform-mcp@5.1.0"],
      "env": {
        "HAPPY_CONFIG_PATH": "~/.config/happy-platform-mcp/instances.json"
      }
    }
  }
}

The package-local config/servicenow-instances.json is a read-only legacy migration input, never the writable v5.1 registry. With the automatic package-legacy-to-user-registry path, happy-platform-mcp instance migrate moves credentials into the OS keychain and leaves the legacy source untouched. If an override points at the same plaintext source and destination, migration refuses before writing; select a distinct target or recreate each instance with instance add. Never teach manual plaintext registry editing.

Step 4: Start Normally or in Docs-Only Mode

When neither a registry/config nor legacy environment credentials exist, stdio automatically falls back to docs-only mode. To force that mode explicitly, configure:

{
  "env": {
    "HAPPY_MCP_DOCS_ONLY": "true"
  }
}

Use HAPPY_MCP_DOCS_ONLY=true; the v5.1 --docs-only flag does not reliably override an existing registry. Docs-only mode exposes the documentation and safe registration tools without creating a live ServiceNow client.

Step 5: Use Safe MCP Registration

SN-Register-Instance is metadata-only and rejects secret fields. It normally persists metadata and performs a live reload. A server that started in docs-only mode must restart before live ServiceNow tools become available.

There is a v5.1 bootstrap constraint: credential-backed registration checks for credential references before it writes new metadata, while instance credential set requires an already-registered name. Therefore:

• Use local instance add for Basic, client_credentials, and OAuth password.
• Direct SN-Register-Instance is reliable for public authorization_code, which has no static client credential.
• Credential-backed direct registration is also possible with externally preprovisioned deterministic keychain refs.
• Never pass a credential or token to SN-Register-Instance.

Example public registration:

Tool: SN-Register-Instance
Parameters:
  name: public-dev
  url: https://example.service-now.com
  authType: oauth
  grantType: authorization_code
  clientId: registered-public-client-id
  makeDefault: true

Step 6: Verify and Route

After restarting the MCP host, list instances with parameterless SN-Set-Instance, inspect the session with SN-Get-Current-Instance, and run a low-risk read:

Tool: SN-Query-Table
Parameters:
  instance: dev
  table_name: incident
  query: active=true
  fields: number,short_description,state
  limit: 1

SN-Set-Instance changes the current session's implicit target for sequential work. For concurrent work, critical operations, or any operation that could race a session switch, pass the explicit per-call instance value.

Best Practices

• Start read-only and in a non-production instance.
• Keep instance names clear and verify the current target before writes.
• Keep credentials inside masked local prompts and the OS keychain.
• Use explicit routing for destructive, production, concurrent, or critical operations.
• Run happy-platform-mcp instance test <name> before enabling write workflows.
• Preserve the MCP-first policy and use SN-Get-Table-Schema before unfamiliar table operations.

Troubleshooting

Issue	Resolution
CLI reports an old Node runtime	Install Node 20 or later and repeat the command
An instance name is missing	Run happy-platform-mcp instance list, then use instance add locally
Authentication mode must change	Run instance remove <name>, then instance add and choose the new mode
Metadata exists but authentication fails	Run instance credential set <name> locally, then instance test <name>
Only docs tools appear	Remove forced docs-only mode if present and restart after a usable registration exists
Migration refuses the path	Use the automatic legacy-to-default-user path or select a distinct metadata-only target

Related Skills

• admin/instance-management - Runtime routing and environment safety
• development/servicenow-docs-mcp - Documentation search and docs-only behavior
• development/mcp-server - Build a custom MCP-compatible integration