Apple Terminal + tmux: diff background blocks render as solid yellow instead of red/green
Open 💬 0 comments Opened Jul 15, 2026 by basrican1
What version of Codex CLI is running?
0.144.4
What subscription do you have?
ChatGPT Plus
Which model were you using?
gpt-5.6-sol, gpt-5.6-luna
What platform is your computer?
Darwin 24.6.0 arm64 arm
What terminal emulator and version are you using (if applicable)?
Apple Terminal.app on macOS 15.7.4 Running inside tmux 3.7b.
Codex doctor report
{
"schemaVersion": 1,
"generatedAt": "1784147884s since unix epoch",
"overallStatus": "ok",
"codexVersion": "0.144.4",
"checks": {
"app_server.status": {
"id": "app_server.status",
"category": "app-server",
"status": "ok",
"summary": "background server is not running",
"details": {
"control socket": "/Users/basrican/.codex/app-server-control/app-server-control.sock",
"daemon state dir": "/Users/basrican/.codex/app-server-daemon",
"mode": "ephemeral",
"pid file": "/Users/basrican/.codex/app-server-daemon/app-server.pid (missing)",
"settings": "/Users/basrican/.codex/app-server-daemon/settings.json (missing)",
"status": "not running",
"update-loop pid file": "/Users/basrican/.codex/app-server-daemon/app-server-updater.pid (missing)"
},
"remediation": null,
"durationMs": 0
},
"auth.credentials": {
"id": "auth.credentials",
"category": "auth",
"status": "ok",
"summary": "auth is configured",
"details": {
"auth file": "/Users/basrican/.codex/auth.json",
"auth storage mode": "File",
"stored API key": "false",
"stored ChatGPT tokens": "true",
"stored agent identity": "false",
"stored auth mode": "chatgpt"
},
"remediation": null,
"durationMs": 0
},
"config.load": {
"id": "config.load",
"category": "config",
"status": "ok",
"summary": "config loaded",
"details": {
"CODEX_HOME": "/Users/basrican/.codex",
"config.toml": "/Users/basrican/.codex/config.toml",
"config.toml parse": "ok",
"cwd": "/Users/basrican/Desktop/CalciumToAnalyze/Zeka/Opto/RGL_iBark",
"enabled feature flags": "shell_tool, unified_exec, shell_snapshot, code_mode_host, terminal_resize_reflow, sqlite, hooks, enable_request_compression, multi_agent, apps, tool_search_always_defer_mcp_tools, tool_suggest, plugins, in_app_browser, browser_use, browser_use_full_cdp_access, browser_use_external, computer_use, remote_plugin, plugin_sharing, image_generation, resize_all_images, skill_mcp_dependency_install, mentions_v2, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, auth_elicitation, personality, fast_mode, tui_app_server, remote_compaction_v2, workspace_dependencies",
"feature flag overrides": "none",
"feature flags enabled": "35",
"log dir": "/Users/basrican/.codex/log",
"mcp servers": "0",
"model": "gpt-5.6-luna",
"model provider": "openai",
"sqlite home": "/Users/basrican/.codex"
},
"remediation": null,
"durationMs": 0
},
"git.environment": {
"id": "git.environment",
"category": "git",
"status": "ok",
"summary": "git version 2.53.0",
"details": {
"PATH git #1": "/opt/homebrew/bin/git",
"PATH git #2": "/usr/bin/git",
"PATH git entries": "2",
"git build options": "git version 2.53.0; cpu: arm64; no commit associated with this build; sizeof-long: 8; sizeof-size_t: 8; shell-path: /bin/sh; rust: disabled; feature: fsmonitor--daemon; gettext: enabled; libcurl: 8.7.1; zlib: 1.2.12; SHA-1: SHA1_DC; SHA-256: SHA256_BLK; default-ref-format: files; default-hash: sha1",
"git exec path": "/opt/homebrew/opt/git/libexec/git-core",
"git version": "git version 2.53.0",
"repo detected": "false",
"selected git": "/opt/homebrew/bin/git"
},
"remediation": null,
"durationMs": 132
},
"installation": {
"id": "installation",
"category": "install",
"status": "ok",
"summary": "installation looks consistent",
"details": {
"PATH codex #1": "/opt/homebrew/bin/codex",
"current executable": "/opt/homebrew/bin/codex",
"install context": "brew",
"managed by bun": "false",
"managed by npm": "false",
"managed by pnpm": "false",
"managed package root": "not set"
},
"remediation": null,
"durationMs": 8
},
"mcp.config": {
"id": "mcp.config",
"category": "mcp",
"status": "ok",
"summary": "no MCP servers configured",
"details": {},
"remediation": null,
"durationMs": 0
},
"network.env": {
"id": "network.env",
"category": "network",
"status": "ok",
"summary": "network-related environment looks readable",
"details": {
"proxy env vars": "none"
},
"remediation": null,
"durationMs": 0
},
"network.provider_reachability": {
"id": "network.provider_reachability",
"category": "reachability",
"status": "ok",
"summary": "active provider endpoints are reachable over HTTP",
"details": {
"ChatGPT base URL": "https://chatgpt.com/backend-api/ reachable (HTTP 404)",
"reachability mode": "ChatGPT auth"
},
"remediation": null,
"durationMs": 259
},
"network.websocket_reachability": {
"id": "network.websocket_reachability",
"category": "websocket",
"status": "ok",
"summary": "Responses WebSocket handshake succeeded",
"details": {
"DNS": "2 IPv4, 2 IPv6, first IPv4",
"auth mode": "chatgpt",
"connect timeout": "15000 ms",
"endpoint": "wss://chatgpt.com/backend-api/<redacted>",
"handshake result": "HTTP 101 Switching Protocols",
"model provider": "openai",
"models etag present": "true",
"provider name": "OpenAI",
"proxy env vars": "none",
"reasoning header": "false",
"server model present": "false",
"supports websockets": "true",
"wire API": "responses"
},
"remediation": null,
"durationMs": 822
},
"runtime.provenance": {
"id": "runtime.provenance",
"category": "runtime",
"status": "ok",
"summary": "running brew on macos-aarch64",
"details": {
"commit": "unknown",
"current executable": "/opt/homebrew/bin/codex",
"install method": "brew",
"platform": "macos-aarch64",
"version": "0.144.4"
},
"remediation": null,
"durationMs": 0
},
"runtime.search": {
"id": "runtime.search",
"category": "search",
"status": "ok",
"summary": "search is OK (system)",
"details": {
"search command": "rg",
"search command readiness": "ripgrep 15.1.0",
"search provider": "system"
},
"remediation": null,
"durationMs": 8
},
"sandbox.helpers": {
"id": "sandbox.helpers",
"category": "sandbox",
"status": "ok",
"summary": "sandbox configuration is readable",
"details": {
"approval policy": "OnRequest",
"codex-linux-sandbox helper": "none",
"execve wrapper helper": "/Users/basrican/.codex/tmp/arg0/codex-arg0I9aZ9P/codex-execve-wrapper",
"filesystem sandbox": "restricted",
"network sandbox": "restricted"
},
"remediation": null,
"durationMs": 0
},
"state.paths": {
"id": "state.paths",
"category": "state",
"status": "ok",
"summary": "state paths and databases are inspectable",
"details": {
"CODEX_HOME": "/Users/basrican/.codex (dir)",
"active rollout files": "35 files, 718260010 total bytes, 20521714 average bytes",
"archived rollout files": "0 files, 0 total bytes, 0 average bytes",
"goals DB": "/Users/basrican/.codex/goals_1.sqlite (file)",
"goals DB integrity": "ok",
"log DB": "/Users/basrican/.codex/logs_2.sqlite (file)",
"log DB integrity": "ok",
"log dir": "/Users/basrican/.codex/log (dir)",
"memories DB": "/Users/basrican/.codex/memories_1.sqlite (file)",
"memories DB integrity": "ok",
"sqlite home": "/Users/basrican/.codex (dir)",
"state DB": "/Users/basrican/.codex/state_5.sqlite (file)",
"state DB integrity": "ok"
},
"remediation": null,
"durationMs": 341
},
"state.rollout_db_parity": {
"id": "state.rollout_db_parity",
"category": "threads",
"status": "ok",
"summary": "rollout files and state DB thread inventory agree",
"details": {
"default model provider": "openai",
"rollout DB active files": "35",
"rollout DB active rows": "35",
"rollout DB archive mismatches": "0",
"rollout DB archived files": "0",
"rollout DB archived rows": "0",
"rollout DB duplicate DB paths": "0",
"rollout DB duplicate rollout thread ids": "0",
"rollout DB malformed file names": "0",
"rollout DB missing active rows": "0",
"rollout DB missing archived rows": "0",
"rollout DB model providers": "openai=35",
"rollout DB rows": "35",
"rollout DB scan cap reached": "false",
"rollout DB scan errors": "0",
"rollout DB sources": "cli=35",
"rollout DB stale rows": "0"
},
"remediation": null,
"durationMs": 2176
},
"system.environment": {
"id": "system.environment",
"category": "system",
"status": "ok",
"summary": "OS language en-US",
"details": {
"EDITOR": "not set",
"LANG": "en_US.UTF-8",
"VISUAL": "not set",
"os": "Mac OS 15.7.4 [64-bit]",
"os language": "en-US",
"os type": "Mac OS",
"os version": "15.7.4"
},
"remediation": null,
"durationMs": 7
},
"terminal.env": {
"id": "terminal.env",
"category": "terminal",
"status": "ok",
"summary": "terminal metadata was detected",
"details": {
"TERM_PROGRAM": "Apple_Terminal",
"color output": "enabled",
"effective locale": "en_US.UTF-8",
"stderr is terminal": "true",
"stdin is terminal": "true",
"stdout is terminal": "true",
"terminal": "Apple Terminal",
"terminal size": "114x59",
"terminal version": "455.1"
},
"remediation": null,
"durationMs": 0
},
"terminal.title": {
"id": "terminal.title",
"category": "title",
"status": "ok",
"summary": "terminal title default",
"details": {
"terminal title activity": "true",
"terminal title items": "activity, project-name",
"terminal title project source": "cwd",
"terminal title project value": "RGL_iBark",
"terminal title source": "default"
},
"remediation": null,
"durationMs": 0
},
"updates.status": {
"id": "updates.status",
"category": "updates",
"status": "ok",
"summary": "update configuration is locally consistent",
"details": {
"cached latest version": "0.144.4",
"check for update on startup": "true",
"last checked at": "2026-07-15T20:14:18.312775Z",
"latest version": "0.144.4",
"latest version status": "current version is not older",
"update action": "brew upgrade --cask codex",
"version cache": "/Users/basrican/.codex/version.json"
},
"remediation": null,
"durationMs": 74
}
}
}What issue are you seeing?
When running Codex CLI inside tmux in Apple Terminal, diff regions that should have red or green background fills are rendered as solid mustard-yellow rectangles.
The underlying text is still present. If I select the region with the mouse, I can see the correct diff text (+/- lines, line numbers, and code). Releasing the mouse restores the yellow rectangles.
The same behavior occurs in the built-in /theme preview, so the issue is not limited to live editing.
<img width="3656" height="1692" alt="Image" src="https://github.com/user-attachments/assets/fce95907-a738-4e99-9a61-abb695181e6a" />
<img width="1604" height="794" alt="Image" src="https://github.com/user-attachments/assets/6aa1531e-bca9-4ada-8b64-58704bfd8ff5" />
What steps can reproduce the bug?
- Open Apple Terminal on macOS.
- Start tmux.
- Launch Codex.
- Open /theme.
or
- Edit an existing file so Codex displays a colored diff.
The diff backgrounds render as solid yellow rectangles instead of red and green.
What is the expected behavior?
Deleted lines should have red backgrounds.
Added lines should have green backgrounds.
The diff should remain readable while editing and in the /theme preview.
Additional information
Environment
• macOS 15.7.4 (24G517)
• Apple Terminal.app
• tmux 3.7b
• Codex CLI 0.144.4
• TERM=tmux-256color
• COLORTERM=truecolor
tmux configuration
set -g default-terminal "tmux-256color"
set -as terminal-features ",xterm-256color:RGB"
Additional testing performed
• ANSI color tests render correctly.
• 24-bit RGB tests render correctly.
• Reproduced in a completely clean tmux server started with:
tmux -L clean -f /dev/null new -s clean
• Reproduced with default tmux configuration.
• Reproduced in the /theme preview.
• Running Codex directly in Apple Terminal (without tmux) renders correctly.
• NO_COLOR=1 avoids the issue by disabling the background fills.