Grossmargin Connect

Team secrets vault and MCP gateway: stores credentials, connects to third-party MCP servers, and serves its own MCP endpoint. Next.js + Prisma + Postgres.

Model

• Team — owns everything. Team↔User is many-to-many. Any member has full read+write on all the team's vaults.

• Vault — a group of credentials in a team.

• Credential — name, description, type (SINGLELINE | MULTILINE | NANGO), and content. Content is encrypted at rest (AES-256-GCM) and decrypts to JSON { "value": "..." }. Name/description/type stay in plaintext.

  • NANGO credentials store no secret. content is null; a credentialRef JSONB ({ connectionId, providerConfigKey }) points at a Nango connection. On reveal, the server fetches a live, auto-refreshed OAuth access token from Nango. To an MCP client this is transparent: the credential lists like any other, and view_credential returns the current token in content (plus realmId and expiresAt for QuickBooks). Needs NANGO_SECRET_KEY in the environment; NANGO_HOST overrides the default https://api.nango.dev.

• ServiceAccount — team-scoped, read-only. Holds one or more keys (sa_...). Keys are shown once at creation, then only as a prefix. Any key works (rotation).

Related MCP server: thales-cdsp-csm-mcp-server

Access

Users sign in with Google. Set AUTH_ALLOWED_DOMAIN to restrict sign-in to one Workspace domain; leave it unset to allow any Google account. A first login creates a User with no team. Add people to teams by editing the database — there are no invitations yet.

Encryption

ENCRYPTION_KEY is a comma-separated list of 32-byte base64 keys, newest first. New content is encrypted with the first key; each record tags which key it used, so old keys still decrypt after rotation.

openssl rand -base64 32   # make a key

MCP

The MCP server is mounted at /mcp (stateless Streamable HTTP). Tools:

• get_vaults — vaults you can access.

• get_credentials(vaultId?) — credential metadata (never content).

• view_credential(credentialId) — decrypted content, or a live Nango token for NANGO creds. Audited.

Two auth paths:

• Service account — Authorization: Bearer sa_.... Scoped to the SA's team, read-only.

• OAuth — standard MCP flow (Dynamic Client Registration + PKCE). The human logs in with Google; the token is scoped to all their teams. Endpoints: /.well-known/oauth-authorization-server, /oauth/register, /oauth/authorize, /oauth/token.

Audit

Every content reveal (view_credential, UI or MCP) and credential create/update is written to AuditLog.

Develop

bun install
cp apps/web/.env.example apps/web/.env   # fill in values
docker compose up -d db
bun run db:push
bun run dev

Deploy

docker compose up --build
bun run db:migrate   # or db:push, against the compose Postgres