feat: A tool to run R code

[gadenbuie]

Closes #118

Summary

This PR adds btw_tool_run_r(), a tool that executes R code in the global environment and returns the results to the LLM. I've marked the tool Experimental for now.

What it captures

The tool captures and returns:

• Text output from print(), cat(), etc.
• Plots as inline images
• Messages from message()
• Warnings from warning()
• Errors from stop()

When an error occurs, all output up to the error is returned.

The tool makes use of recent changes in ellmer v0.4.0 to allow tools to return lists of Content, include ContentImage types from plots. Each of the above output types are given btw-local content types which are also used to customize their display in shinychat.

Security

This tool is disabled by default. It executes arbitrary code in the global environment without sandboxing or review. We recommend:

• Only enable in trusted, non-public environments
• Avoid prompting the model to take destructive actions
• Understand the security risks before enabling

To enable the tool

The tool can be enable via an R option (in a session, an .Rprofile or in btw.md):

options(btw.run_r.enabled = TRUE)

---
options:
  run_r:
    enabled: true
---

Or equivalently via environment variable:

BTW_RUN_R_ENABLED=true

When this option is set, btw_tools() will include the btw_tool_run_r() tool, otherwise it is excluded from btw_tools().

In btw_tools(), you can also explicitly include the "run", "run_r" or "btw_tool_run_r" tool in tools:

btw_tools(tools = "run_r")

Or in btw.md:

---
tools:
  - run_r
---

Dependencies

This feature adds a few additional suggested dependencies.

• We use evaluate for running and evaluating the LLM-written code
• If fansi is available, we use it to translate ANSI colors to HTML
• If ragg is available, we use it as the plot rendering device. The plot device can be customized by providing a function via the R option btw.run_r.graphics_device.

[simonpcouch]

So sharp. Interleaving that output is so nice. This looks great!

Models' "default" Amount Of Code Written when calling this tool still feels too long to me. This leads to issues like that below, where the model hallucinates column names in data is hasn't seen yet because it didn't stop to examine the output of glimpse(forested). We've prompted PA/Databot/side::kick() in the same way in their analogous tools for this reason.

If you still disagree, okay with me that maybe this is a matter of preference best resolved in our btw.mds. :)

[simonpcouch]

Is there any way could suppress package startup messages by default in the tool UI?

[gadenbuie]

Models' "default" Amount Of Code Written when calling this tool still feels too long to me. This leads to issues like that below, where the model hallucinates column names in data is hasn't seen yet because it didn't stop to examine the output of glimpse(forested). We've prompted PA/Databot/side::kick() in the same way in their analogous tools for this reason.

@simonpcouch ah that's a great point; thanks for showing me the example. I didn't take those lines initially because there are some shinychat limitations we need to fix around how the tool UI works when you're streaming in results. So I wasn't sure if I wanted to create a situation where the model tries to run code in too small of a chunk and ends up making that problem worse. I think I'll go back and add those lines in though after seeing your example.

I'll look into suppressing package startup messages too!