mcp-saas-connector

One MCP server for the SaaS back office. Stripe, HubSpot, and Google Sheets exposed as typed, read-only-by-default tools for Claude and any MCP client.

Most teams that connect an agent to their business systems end up running three separate servers with three different auth stories and three different ideas of what a safe default looks like. This server takes the opposite approach: one process, one configuration surface, one security model, and a tool catalog designed for how agents actually consume data.

Design principles

• Read-only by default. Tools that create or modify data exist, but they register only when you set CONNECTOR_ALLOW_WRITES=true. There are no destructive tools at all: nothing deletes, refunds, or overwrites.
• Token-disciplined responses. Provider APIs return large payloads. Every tool maps them to the compact set of fields an agent acts on, so a customer lookup costs a few hundred tokens instead of a few thousand.
• Secrets never reach the model. Error messages pass through a redaction layer that strips API keys, bearer tokens, and private key material before anything is surfaced.
• Two dependencies. The MCP SDK and zod. Google auth is a hand-built RS256 service-account JWT, not the full googleapis client.

Quickstart

Requires Node 18 or newer.

Claude Code

claude mcp add saas \
  --env STRIPE_API_KEY=rk_live_... \
  --env HUBSPOT_ACCESS_TOKEN=pat-... \
  -- npx -y @juliatechnologies/mcp-saas-connector

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "saas": {
      "command": "npx",
      "args": ["-y", "@juliatechnologies/mcp-saas-connector"],
      "env": {
        "STRIPE_API_KEY": "rk_live_...",
        "HUBSPOT_ACCESS_TOKEN": "pat-..."
      }
    }
  }
}

From source

git clone https://github.com/JuliaTechnologies/mcp-saas-connector.git
cd mcp-saas-connector
npm install
npm test
node dist/index.js

Providers turn on individually: set a credential and its tools register, leave it unset and they stay off. With no credentials at all the server still starts and exposes connector_status, which explains its own setup state.

Configuration

Variable	Enables	Notes
STRIPE_API_KEY	Stripe tools	Use a restricted key (rk_...) with read permissions
HUBSPOT_ACCESS_TOKEN	HubSpot tools	Private app token scoped to contacts and deals
GOOGLE_SERVICE_ACCOUNT_JSON	Google Sheets tools	Inline JSON or a path to the key file. Share target sheets with the service account email
CONNECTOR_ALLOW_WRITES	Write tools	true registers the three write tools below. Anything else keeps them off

Tool catalog

Tool	Provider	Mode	What it does
connector_status	core	read	Reports enabled providers and write state
stripe_list_customers	Stripe	read	List customers, optional exact-email filter
stripe_get_customer	Stripe	read	One customer with balance and metadata
stripe_list_subscriptions	Stripe	read	Subscriptions by customer and status
stripe_list_invoices	Stripe	read	Invoices with totals and hosted links
stripe_list_payment_intents	Stripe	read	Recent payments with status
hubspot_search_contacts	HubSpot	read	Full-text contact search
hubspot_get_contact	HubSpot	read	One contact with associated deal ids
hubspot_list_deals	HubSpot	read	Deals with stage, amount, cursor paging
hubspot_get_deal	HubSpot	read	One deal by id
sheets_list_tabs	Sheets	read	Tabs and grid sizes of a spreadsheet
sheets_read_range	Sheets	read	Cell values from an A1 range
hubspot_create_contact	HubSpot	write	Create a contact
hubspot_create_note	HubSpot	write	Attach a timestamped note to a contact
sheets_append_row	Sheets	write	Append one row to a tab

Security model

The full policy lives in SECURITY.md. The short version: least-privilege credentials are assumed, write tools are an explicit opt-in, secrets are redacted from all output, stdout is reserved for the MCP protocol, and the server sends nothing anywhere except the provider APIs you configure. No telemetry.

Roadmap

• Streamable HTTP transport for remote deployment behind OAuth
• Per-tool allowlists so operators can expose a subset of a provider
• More providers: Salesforce, Notion, Slack
• An eval harness for tool-call correctness

Issues and pull requests are welcome.

Who maintains this

Julia Technologies is a one-architect consultancy that designs and builds production MCP servers for B2B SaaS products. This connector is the open-source expression of how those servers should be built: narrow tools, safe defaults, disciplined responses. If your product needs to be usable by Claude and other AI agents, that is the work Julia Technologies does.

License

MIT. See LICENSE.