codexR

codexR is a small R package that lets you call the local Codex CLI from an open .R file in RStudio or RStudio Server.

Install

From a local source checkout:

install.packages(".", repos = NULL, type = "source")

From GitHub via remotes:

remotes::install_github("s-geissler/codexR")

Basic use

Load the package once in your session:

library(codexR)
codex_init(quiet = TRUE)

Then place a line like this in an open .R file and source that line:

codex("Explain why this function is failing and suggest a fix.")

By default the package sends:

• your prompt
• the active document path
• the active cursor position
• the full active document contents
• a small amount of session context

When called from RStudio or RStudio Server, codex() also rewrites the active editor buffer by default:

• the invoked codex("...") line is converted into an R comment
• the Codex response is inserted directly below that commented line
• the response is inserted only if it parses as valid R code

If Codex returns non-R text or syntactically invalid R, codex() stops with an error and does not modify the editor.

Object Metadata

You can provide object names from the calling environment:

codex("Iterate over df_data", objects = "df_data")

The package sends metadata only. It does not send raw values, rows, vector contents, or list contents to Codex. For example, for a data frame it includes schema-style information such as:

• class
• type
• dimensions
• column names
• column types

For lists, matrices, arrays, and vectors it only includes structural metadata such as length, dimensions, names, and element classes.

The metadata exporter is allowlist-based. Each supported object class has an explicit set of permitted fields, and unknown classes fall back to a very small structural summary only.

Variants

Use only the current selection:

codex("Refactor this block for clarity.", scope = "selection")

Disable editor write-back and only print the response:

codex("Refactor this block for clarity.", write_back = FALSE)

Select a specific Codex binary and set session defaults:

codex_init(
  codex_bin = "/home/youruser/.local/bin/codex",
  quiet = TRUE,
  write_back = TRUE
)

With quiet = TRUE, codexR suppresses both its own console printing and normal stdout/stderr chatter from the Codex CLI during successful runs.

Write the final Codex response to a file instead of printing it:

path <- codex(
  "Summarize this script and suggest tests.",
  output = "file",
  write_back = FALSE
)
cat(readLines(path), sep = "\n")

Pass extra flags directly to the Codex CLI:

codex(
  "Review this script for bugs.",
  codex_args = c("--model", "gpt-5.4", "--full-auto")
)

Requirements

• codex must be installed and available on PATH
• rstudioapi must be installed
• for best results, run from an open file in RStudio or RStudio Server

Development

Run a local package check:

devtools::check()

The repository also includes a GitHub Actions workflow for R CMD check.