Open Agent Platform only supports connecting to MCP servers which support Streamable HTTP requests. As of 05/10/2025, there aren’t many MCP servers which support this, which is why we’ve released the demo application connected to Arcade’s MCP server.
Open Agent Platform was built with first class support for connecting agents to MCP servers which support Streamable HTTP requests. You can configure your MCP server in one of two ways. First, set your MCP server URL under the environment variable NEXT_PUBLIC_MCP_SERVER_URL inside the apps/web/ directory. Ensure this URL does not end in /mcp, as the OAP web app will append this to the URL when making requests to the MCP server. E.g. if your MCP server URL is: 
https://api.arcade.dev/v1/mcps/ms_0ujssxh0cECutqzMgbtXSGnjorm/mcp
You should set the environment variable as: 
NEXT_PUBLIC_MCP_SERVER_URL="https://api.arcade.dev/v1/mcps/ms_0ujssxh0cECutqzMgbtXSGnjorm" # no /mcp

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Authenticated Servers

To connect to an MCP server which requires authentication, you should set NEXT_PUBLIC_MCP_AUTH_REQUIRED=true. The way MCP authentication works is as follows: The web client makes a request to the proxy route (/api/oap_mcp). Inside this API route, we use Supabase’s JWT to authenticate with the MCP server. This means you must implement an endpoint on your MCP server which allows for exchanging a Supabase JWT (or any other JWT if you choose to use a different authentication provider) for an MCP access token. This access token is then used to authenticate requests to the MCP server. After this exchange, we use the MCP access token to make requests to the MCP server on behalf of the user, passing it through the Authorization header of the request. When sending the request response back to the client, we include the MCP access token in the x-mcp-access-token header of the response. This allows the client to use the MCP access token in future requests to the MCP server, without having to authenticate with the MCP server each time. It’s set to expire after one hour by default. The URL set to NEXT_PUBLIC_MCP_SERVER_URL must be formatted so that the proxy route can append /mcp at the end to make requests to the MCP server, and /oauth/token at the end to make requests to the MCP server’s OAuth token endpoint. Optionally, you can set the MCP_TOKENS environment variable to contain an object with an access_token field. If this environment variable is set, we will attempt to use that access token to authenticate requests to the MCP server. This is useful for testing, or if you want to use a different authentication provider than Supabase.

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Unauthenticated Servers

To connect to an MCP server which does not require authentication, you should set the NEXT_PUBLIC_MCP_SERVER_URL environment variable to the URL of your MCP server. If this URL is set, and NEXT_PUBLIC_MCP_AUTH_REQUIRED is not set/not set to true, we will not execute the OAuth request in the proxy route, and instead directly call your MCP server.

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Changing MCP Server URL

If you change the MCP server URL, you’ll need to update all of your agents to use the new URL. We’ve included a script in this repo to do just that. This script can be found in apps/web/scripts/update-agents-mcp-url.ts. To update your agent’s MCP server URL, ensure the latest MCP server URL is set under the environment variable NEXT_PUBLIC_MCP_SERVER_URL, along with your deployments under NEXT_PUBLIC_DEPLOYMENTS, and a LangSmith API key under LANGSMITH_API_KEY (this is because the script uses LangSmith auth to authenticate with your LangGraph server, bypassing any user authentication). Then, run the script: 
# Ensure you're inside the `apps/web` directory
cd apps/web

# Run the script via TSX.
npx tsx scripts/update-agents-mcp-url.ts
This will fetch every agent, from every deployment listed. It then checks to see if a given agent supports MCP servers. If it does it checks the MCP server URL is not already set to the new URL. If it is not, it updates the agent’s config to use the new URL.