How to get database/Redis connection URLs via MCP? (or feature request if not currently possible)

[earino]

Hey Render team!

I'm working on deploying a Rails 8 application using the Render MCP, and I've hit a snag that I'm hoping you can help with.

What I'm trying to do

I'm automating the deployment of a Rails app that needs to connect to both a Postgres database and a Redis instance. I can successfully create all three services using the MCP:

• Postgres database via create_postgres
• Redis instance via create_key_value
• Web service via create_web_service

But now I need to connect the web service to the database and Redis by setting DATABASE_URL and REDIS_URL environment variables.

The problem

When I use get_postgres and get_key_value, I get back useful metadata (id, name, region, status, etc.), but I don't see the actual connection URLs (internal or external connection strings) that I need to set as environment variables.

What I've learned

I can see from your Blueprint documentation that connection strings are available via the connectionString property:

  envVars:
    - key: DATABASE_URL
      fromDatabase:
        name: mysite-db
        property: connectionString

And I know from your docs that both internal and external URLs exist:

• Internal: postgresql://USER:PASSWORD@INTERNAL_HOST:PORT/DATABASE
• External: postgresql://USER:PASSWORD@EXTERNAL_HOST:PORT/DATABASE

My questions

1. Am I approaching this wrong? Is there a better way to programmatically link services via the MCP that I'm missing?
2. If not, would it be possible to include connection URLs in the responses from get_postgres and get_key_value? This would enable fully automated deployments without requiring manual dashboard configuration.

I really appreciate all the work you've put into the MCP - it's been super helpful so far! Just want to make sure I'm using it the right way before requesting a feature that might not be needed.

Thanks for any guidance you can provide!

[aaijazi]

Hi,

Thanks for raising this!

This behavior is actually intentional: we removed the connection URLs from the MCP server responses because they contain sensitive information like passwords that users may not want to put in their LLM context.

I have a workaround in mind that I haven't gotten around to implementing yet. My idea is to implement a tool link_service_to_datastore which would take in the serviceID that you want to update, the datastore name that you want to link it to, and the env var name you want to use to link it. Then, the tool could make the appropriate REST calls to update the env var of the service with the datastore's connection string, without that information going into the LLM context.

Do you think that would work for you?