Positron not loading Anthropic API keys from R environment vars

[codeswitching]

In the Configure Language Model Providers dialog, it says:
"You can also assign the ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL environment variables and restart Positron."

I have both of these defined in my .Renviron file, and can confirm that they are loaded into the environment.

Yet even after restarting Positron, I cannot authenticate with Anthropic. (If I enter the key directly into the dialog, it works fine).

[juliasilge]

Ah, I can see how this might be confusing. .Renviron is read by R itself, not by Positron.

When R starts up it reads .Renviron and sets those variables in its own process environment. So Sys.getenv("ANTHROPIC_API_KEY") in the R console shows the value, and everything looks correct from inside R. But the R session is a child process that lives inside Positron, and the variables only exist there. The assistant looks for ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL in Positron's own environment, which never sees .Renviron:

flowchart TB
    shell["Shell config<br/>(~/.zshenv, ~/.zprofile, ...)"]
    renviron["~/.Renviron"]

    subgraph positron["Positron"]
        assistant["Assistant<br/>looks for ANTHROPIC_API_KEY<br/>in Positron's environment"]
        rsession["R session<br/>(child process)<br/>Sys.getenv() sees the key"]

        assistant -- "sends code, asks for variables" --> rsession
        rsession -- "returns output and results" --> assistant
    end

    shell == "environment inherited when Positron starts" ==> positron
    renviron -. "read by R alone, when the R session starts" .-> rsession

Loading

Notice the dotted arrow and how it stops at the R session and never reaches the assistant.

To make the variables visible to Positron itself, set them in your shell environment rather than in .Renviron:

• macOS / Linux: add export ANTHROPIC_API_KEY=... and export ANTHROPIC_BASE_URL=... to your login shell config (~/.zshenv, ~/.zprofile, or ~/.bash_profile), then fully quit and reopen Positron. Positron resolves your login shell environment at startup, so this works even when you launch from the Dock or Applications folder rather than from a terminal.
• Windows: set them as user environment variables (System Properties > Environment Variables), then restart Positron.

You can leave them in .Renviron too if R packages like ellmer need them there; the two are independent.

That said, entering the key directly in the dialog is a perfectly good option too. It gets stored in your OS keychain rather than sitting in a dotfile, so there is no need to switch if that is working for you.

[codeswitching]

Thank you for the detailed explanation @juliasilge ! As I windows user I rarely add things to the shell environment, but in retrospect it makes sense that that's where Positron would look.