Nimbus MCP Server

Home Services MCP Server

An open-source, self-hostable Model Context Protocol server for home-service discovery, provider profiles and reviews, homeowner identity, booking requests, and booking follow-up. The server supplies the workflow and MCP interface; each operator supplies the APIs, data, credentials, branding, and deployment environment.

This repository contains no customer data, provider data, API keys, or private production endpoints. It includes one documented public hosted MCP fallback for convenience; operators can replace it with their own endpoint and credentials for a fully self-hosted deployment.

What is included

• Streamable HTTP MCP transport at /mcp (the root endpoint is also mapped for clients that require it).
• OAuth 2.0 authorization-code flow with PKCE, when OAuth credentials are configured.
• Provider search, details, reviews, homeowner profile, booking, previous-job, booking-status, and rebooking workflows.
• Optional category-specific find/book tool aliases.
• Input validation, PII-aware logging, outbound host allowlisting, rate limiting, and circuit-breaker behavior.
• Local ASGI development, a generic Docker image, and AWS SAM/Lambda deployment configuration.

The public MCP contract is intentionally stable. Operators can replace the backends without changing the client-facing tool names or workflow semantics.

Quick start

python3.10 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env
# The default setup uses the hosted MCP relay. For self-hosting, edit .env
# with your own upstream MCP endpoint, API URLs, and credentials.
uvicorn src.main:app --reload --port 8000

The server is then available at http://localhost:8000/mcp.

Before opening a release or marketplace review, run the checks in docs/RELEASE_CHECKLIST.md, including:

python3 scripts/audit_public_release.py

For a container build:

docker build -t home-services-mcp .
docker run --env-file .env -p 8000:8080 home-services-mcp

For AWS SAM, provide deployment-specific values through parameter overrides or your secret manager. Do not place secrets in template.yaml, samconfig files, container layers, or source control.

Configuration

Start with .env.example. Empty optional endpoint variables disable the related capability. The upstream MCP relay is the exception: it defaults to the documented public hosted service and can be overridden.

Core operator-owned endpoints:

Optional integrations include notification endpoints, operator persistence, monitoring webhooks, OAuth, and the OpenAI app verification challenge. All URLs and secrets must be supplied by the operator.

OAuth interoperability

When OAuth is enabled, access and refresh tokens use separate ES256 signing keys; the access-token public verification key is exposed through the metadata jwks_uri. Set OAUTH_ALLOWED_REDIRECT_URIS to the exact hosted or claimed-scheme callbacks your clients use. Native clients may register HTTP loopback callbacks on localhost, 127.0.0.1, or [::1] with any explicit port; these do not need to be enumerated because native apps commonly bind an ephemeral port. Other custom schemes (including arbitrary cursor:// or vscode:// callbacks) are rejected unless their complete URI is explicitly configured, since dynamic registration alone does not prove ownership of a private scheme. Enable OAUTH_DYNAMIC_CLIENT_REGISTRATION_ENABLED to let public PKCE clients obtain unique persisted client ids from /oauth/register; the legacy configured client id and unregistered PKCE clients remain supported.

Use at least 32 cryptographically random bytes for OAUTH_CLIENT_SECRET. The server derives domain-separated ES256 keys from that secret so stateless instances publish and verify the same access-token key without reusing it for refresh-token signatures. OAuth tokens carry an opaque homeowner session id; profile PII and upstream bearer credentials remain in the server-side state store.

Upstream MCP relay

By default, the server relays requests from /upstream/mcp to https://mcp.hirenimbus.com/mcp. Set UPSTREAM_MCP_URL to use an operator-controlled MCP service instead. If the selected upstream requires authentication, set UPSTREAM_MCP_AUTH_TOKEN; no token is bundled, and inbound client authorization is never forwarded automatically.

Review the selected upstream's data handling, retention, terms, and access policy before sending user requests to it. For a fully self-hosted deployment, replace the default upstream and configure the operator-owned business APIs.

Security and data ownership

The server is a programmable integration layer, not a data processor with a built-in tenant. Operators are responsible for:

• API authorization, tenant isolation, data retention, backups, and deletion;
• secret storage, rotation, least-privilege scopes, and production network policy;
• privacy notices, terms, support contacts, regional/legal requirements, and any third-party processing disclosures;
• confirming that configured APIs do not return more personal information than the MCP client needs.

The default development configuration leaves external business APIs empty. Production deployments should fail closed when a required capability is not configured, use durable shared state for OAuth and idempotency, and keep monitoring disabled unless its endpoint is explicitly configured. Set AUTH_STATE_TABLE_NAME to a shared DynamoDB table and REQUIRE_DURABLE_STATE=true for multi-instance OAuth or booking workloads. Without those settings, the development fallback is process-local and does not provide cross-instance replay protection.

Confirmed booking calls accept an optional client-generated idempotency_key. Clients should reuse that key after a timeout. The configured booking API should also honor the same field; the server never retries an ambiguous booking request automatically.

Testing

Install the development dependencies and run:

pytest -q
ruff check .

Tests must use mocks or local fixtures for external integrations. They must not call a live operator endpoint.

Marketplace package

The server and portable workflow skills are independent of any hosted deployment. A first-party distribution can add a separate marketplace manifest that points to its own hosted MCP URL and branded app, without putting those values in this repository.

The portable home-service workflow is available at skills/home-service-concierge/SKILL.md. Its app handoff uses the operator-configured APP_LINK value.

License

Licensed under the Apache License 2.0. Product names, trademarks, private services, and operator integrations are not included as defaults by this codebase. The documented public hosted MCP fallback is an intentional exception and does not include credentials or customer data.