CDT Express MCP Server

Interact with climate metrics through Riskthinking.AI's CDT Express API in supported AI chat experiences.

This project contains:

• The core MCP server for the Riskthinking.AI CDT Express API.
• A remote Streamable HTTP server that users can connect to by URL and

authorize with their VELO account.

• A distributable MCPB extension for Claude Desktop, published through

GitHub releases.

Remote MCP

Add this URL as a custom MCP server in a compatible AI app:

https://mcp.riskthinking.ai/mcp

The app opens VELO for sign-in or sign-up. After consent, authorization completes automatically: the CDT API key is provided to the MCP server through a server-to-server backchannel and is never shown to the AI app, browser URL, or MCP logs.

• ChatGPT: enable Developer mode, create a custom app, and enter the URL.
• Claude web/desktop: add a custom connector using the URL.
• Gemini: eligible Gemini Spark users can add a custom app using the URL.

Gemini CLI can also connect to it as a Streamable HTTP MCP server.

See the remote MCP live-testing guide for current platform requirements, setup steps, and acceptance checks.

The existing MCPB/stdio package remains available for local-only use.

Run the remote server

cp .env.example .env
# Set MCP_OAUTH_SECRET in .env to the output of: openssl rand -base64 48
npm ci
npm run build
npm run start:http

Alternatively, build and run the included Dockerfile. Production requires HTTPS at MCP_PUBLIC_BASE_URL. The Cloud Run disaster-recovery guide covers WIF/IAM provisioning, GitHub configuration, and Cloudflare DNS. Configure the visual-eyes deployment with CDT_MCP_URL=https://mcp.riskthinking.ai/mcp so its /mcp/authorize route can complete the authenticated hand-off.

The HTTP server provides:

• Streamable HTTP at /mcp, with JSON responses for broad client

compatibility.

• OAuth protected-resource and authorization-server discovery.
• OAuth 2.1 authorization code flow with S256 PKCE and RFC 8707 resource

binding.

• Client ID Metadata Documents (CIMD) for any standards-compliant HTTPS client,

with public-IP-pinned fetching, redirect rejection, strict size/time limits, and dynamic client registration for backward compatibility.

• One-hour encrypted access tokens and 30-day encrypted refresh tokens, with

no credential database required.

• Exact callback validation against each client's registered or fetched

metadata, bearer checks on every MCP request, per-authorization session binding, host/origin validation, and bounded request bodies.

MCP_OAUTH_SECRET is the only durable secret and must be shared by all remote MCP instances. Rotating it invalidates existing client registrations and tokens. The current TypeScript SDK negotiates MCP through 2025-11-25, which the major hosted clients currently use. The endpoint is structured for the stateless 2026-07-28 transport and can switch when the stable TypeScript SDK exposes that protocol revision.

MCPB Extension Installation

1. Download and install

Claude Desktop.

1. Download cdt-express.mcpb from the

GitHub releases page.

1. In Claude Desktop, open Settings > Extensions > Advanced settings.
2. Select Install Extension and choose the downloaded MCPB file.
3. When prompted, enter the CDT Express API key from

VELO.

1. Review and enable the extension, then close the preview.
2. On its first tool call, select Allow once or Always allow. Tool

permissions can also be configured under Settings > Extensions.

To update the extension, install the newer MCPB file and select Update.

Roadmap

CDT Express Climate API:

• [x] Since v0.1.0:

Climate exposure metrics

• [x] Since v0.2.0:

Climate impact metrics

• [x] Since v0.2.0:

Probability-adjusted impact

• [x] Since v0.2.0:

Climate exposure distribution

• [x] Since v0.2.0:

Climate impact distribution

Other CDT Express APIs:

• [x] Since v0.3.0:

Physical Assets API

• [x] Since v0.3.0:

Companies API

• [x] Since v0.3.0:

Markets API

Integration:

• [x] Since v0.1.0: stdio transport for local MCP connectivity, including

the Claude Desktop extension and IDEs such as Cursor.

• [x] Since v0.6.0: authenticated Streamable HTTP transport for remote MCP

connectivity to web AI chat experiences.

Development

• Optionally use nvm with nvm use to select

the Node.js version in .nvmrc.

• Install dependencies with npm install.
• Build and package the extension with npm run pack. The resulting

cdt-express.mcpb file is written to the repository root. The command bundles only the local stdio server into an isolated staging directory, leaving the remote HTTP/OAuth server and its dependencies out of the extension.

• Run the remote OAuth and MCP integration tests with npm test.

Release

1. Run npm run bump:version -- <version>. The command treats package.json

as the source of truth and synchronizes the lockfile, server.json, manifest.json, and the runtime SERVER_VERSION constant. It does not create a Git tag; the GitHub release does that after the change is merged.

1. Create a GitHub release and tag using the version with a v prefix, such as

v0.5.2, from the new release page.

1. The release workflow validates the versions, builds the MCPB extension, and

publishes it to the MCP Registry.

MCP Registry server.json

The checked-in file is a valid remote-only server definition. The release workflow calculates the MCPB hash and download URL, adds the complete packages[0] record, validates the result, and publishes both installation options together. See the MCP Registry documentation for the current publishing process.

MCPB manifest.json

npm run pack synchronizes the staged manifest version from package.json without modifying the checked-in manifest.json. See the MCPB manifest specification for current requirements.