26c9502121
## Stack - **Base: #24489 [1 of 2]** - render markdown tables in app style. - **Current: #24636 [2 of 2]** - render cramped markdown tables as key/value records. Review this PR against `fcoury/app-style-markdown-tables`; it contains only the fallback behavior for cramped tables. ## Why The row-separated markdown table rendering in #24489 remains readable while columns have usable room. Once long links or multiple prose-heavy columns are compressed into narrow allocations, however, the grid can turn words and paths into tall vertical strips that are difficult to scan. In those cases the content matters more than preserving the grid shape. ## What Changed <table> <tr><td> <p align="center"><b> Normal </b></p> <img width="1722" height="619" alt="CleanShot 2026-05-27 at 14 32 57" src="https://github.com/user-attachments/assets/d04f5fbd-6064-4acd-91bd-072d19b983df" /> </td></tr> <tr><td> <p align="center"><b> Narrow </b></p> <img width="863" height="1013" alt="CleanShot 2026-05-27 at 14 33 12" src="https://github.com/user-attachments/assets/6a7d2968-0a68-48fd-ab5d-209b3dbaf03e" /> </td></tr> <tr><td> <p align="center"><b> Very narrow </b></p> <img width="435" height="746" alt="CleanShot 2026-05-27 at 14 33 47" src="https://github.com/user-attachments/assets/f6a59e30-b1d2-4063-9c05-43933abc77d6" /> </td></tr> </table> - Detect tables whose grid allocation causes systemic token fragmentation or starves multiple prose-heavy columns. - Render those tables as repeated key/value records instead of retaining an unreadable grid. - Use aligned label/value records when there is useful horizontal room, and switch to a stacked narrow-record layout where each label is followed by a full-width value when width is especially constrained. - Preserve the themed label color, rich inline formatting, links, and the existing grid presentation for tables that remain readable. - Add snapshot coverage for path-heavy narrow tables, prose-heavy issue tables, systemic compact fragmentation, and a control case that should continue to render as a grid. ## How to Test 1. Start Codex from this branch and render a normal multi-column markdown table at a comfortable terminal width. Confirm it still appears as the styled row-separated grid from #24489. 2. Render a table containing a long linked record identifier or file-like value, then narrow the terminal until the grid would split the value into vertical fragments. Confirm it switches to key/value records, with labels above values at very narrow widths. 3. Render a table with multiple prose-heavy columns, such as an issue summary table with `Issue`, `Activity`, `Complexity`, and `Why start`. Confirm a cramped width switches to records rather than wrapping several columns into hard-to-read strips. 4. Render a compact table where only one value wraps mildly. Confirm it stays in grid form rather than switching prematurely. ## Validation - Ran `just test -p codex-tui` while developing the fallback and reviewed/accepted the intended new markdown-render snapshots. The command still reports two unrelated existing guardian feature-flag test failures outside this diff. - Ran `just fix -p codex-tui` and `just fmt` after the Rust changes were complete. - `just argument-comment-lint` cannot reach source linting locally because Bazel fails while resolving LLVM sanitizer headers; touched positional literal callsites were inspected manually and annotated where needed.
Codex CLI (Rust Implementation)
We provide Codex CLI as a standalone executable to ensure a zero-dependency install.
Installing Codex
Today, the easiest way to install Codex is via npm:
npm i -g @openai/codex
codex
You can also install via Homebrew (brew install --cask codex) or download a platform-specific release directly from our GitHub Releases.
Documentation quickstart
- First run with Codex? Start with
docs/getting-started.md(links to the walkthrough for prompts, keyboard shortcuts, and session management). - Want deeper control? See
docs/config.mdanddocs/install.md.
What's new in the Rust CLI
The Rust implementation is now the maintained Codex CLI and serves as the default experience. It includes a number of features that the legacy TypeScript CLI never supported.
Config
Codex supports a rich set of configuration options. Note that the Rust CLI uses config.toml instead of config.json. See docs/config.md for details.
Model Context Protocol Support
MCP client
Codex CLI functions as an MCP client that allows the Codex CLI and IDE extension to connect to MCP servers on startup. See the configuration documentation for details.
MCP server (experimental)
Codex can be launched as an MCP server by running codex mcp-server. This allows other MCP clients to use Codex as a tool for another agent.
Use the @modelcontextprotocol/inspector to try it out:
npx @modelcontextprotocol/inspector codex mcp-server
Use codex mcp to add/list/get/remove MCP server launchers defined in config.toml, and codex mcp-server to run the MCP server directly.
Notifications
You can enable notifications by configuring a script that is run whenever the agent finishes a turn. The notify documentation includes a detailed example that explains how to get desktop notifications via terminal-notifier on macOS. When Codex detects that it is running under WSL 2 inside Windows Terminal (WT_SESSION is set), the TUI automatically falls back to native Windows toast notifications so approval prompts and completed turns surface even though Windows Terminal does not implement OSC 9.
codex exec to run Codex programmatically/non-interactively
To run Codex non-interactively, run codex exec PROMPT (you can also pass the prompt via stdin) and Codex will work on your task until it decides that it is done and exits. If you provide both a prompt argument and piped stdin, Codex appends stdin as a <stdin> block after the prompt so patterns like echo "my output" | codex exec "Summarize this concisely" work naturally. Output is printed to the terminal directly. You can set the RUST_LOG environment variable to see more about what's going on.
Use codex exec --ephemeral ... to run without persisting session rollout files to disk.
Experimenting with the Codex Sandbox
To test to see what happens when a command is run under the sandbox provided by Codex, use the sandbox subcommand in Codex CLI:
# Uses the sandbox implementation for the current host OS:
# Seatbelt on macOS, the Linux sandbox on Linux, and Windows restricted token on Windows.
codex sandbox [COMMAND]...
# macOS-only diagnostic option
codex sandbox --log-denials [COMMAND]...
codex sandbox also accepts --profile NAME (-p NAME) to layer
$CODEX_HOME/NAME.config.toml onto the base user config for the sandboxed
command.
Selecting a sandbox policy via --sandbox
The Rust CLI exposes a dedicated --sandbox (-s) flag that lets you pick the sandbox policy without having to reach for the generic -c/--config option:
# Run Codex with the default, read-only sandbox
codex --sandbox read-only
# Allow the agent to write within the current workspace while still blocking network access
codex --sandbox workspace-write
# Danger! Disable sandboxing entirely (only do this if you are already running in a container or other isolated env)
codex --sandbox danger-full-access
In workspace-write, Codex also includes ~/.codex/memories in its writable roots so memory maintenance does not require an extra approval.
Code Organization
This folder is the root of a Cargo workspace. It contains quite a bit of experimental code, but here are the key crates:
core/contains the business logic for Codex. Ultimately, we hope this becomes a library crate that is generally useful for building other Rust/native applications that use Codex.exec/"headless" CLI for use in automation.tui/CLI that launches a fullscreen TUI built with Ratatui.cli/CLI multitool that provides the aforementioned CLIs via subcommands.
If you want to contribute or inspect behavior in detail, start by reading the module-level README.md files under each crate and run the project workspace from the top-level codex-rs directory so shared config, features, and build scripts stay aligned.