Codex

Codex is OpenAI's command-line coding tool (Codex CLI). This page covers its global instructions, MCP servers, shell functions and common commands.

Configuration#

Codex keeps its config files in the ~/.codex directory.

Global instructions#

Put the following in ~/.codex/AGENTS.md:

MCP servers#

Add the following to ~/.codex/config.toml:

toml

[mcp_servers.claude-code]command = "claude"args = ["mcp", "serve"]
[mcp_servers.context7]command = "npx"args = ["-y", "@upstash/context7-mcp"]
[mcp_servers.shadcn]command = "npx"args = ["shadcn@latest", "mcp"]

[mcp_servers.claude-code]command = "claude"args = ["mcp", "serve"]
[mcp_servers.context7]command = "npx"args = ["-y", "@upstash/context7-mcp"]
[mcp_servers.shadcn]command = "npx"args = ["shadcn@latest", "mcp"]

Shell function#

Wrap codex in a shell function of the same name so every launch gets the base arguments. Add the function to ~/.zshrc or your PowerShell $PROFILE. Pick one of the two variants below.

Always start a new session#

Start a fresh session every time, with only the base arguments.

Zsh:

zsh

codex() {  local base_args="--dangerously-bypass-approvals-and-sandbox"
  command codex ${=base_args} "$@"}

codex() {  local base_args="--dangerously-bypass-approvals-and-sandbox"
  command codex ${=base_args} "$@"}

PowerShell:

powershell

function codex {    $baseArgs = @("--dangerously-bypass-approvals-and-sandbox")    $codexPath = (Get-Command codex -CommandType Application | Select-Object -First 1).Source
    & $codexPath @baseArgs @args}

function codex {    $baseArgs = @("--dangerously-bypass-approvals-and-sandbox")    $codexPath = (Get-Command codex -CommandType Application | Select-Object -First 1).Source
    & $codexPath @baseArgs @args}

Resume the current directory's session automatically#

Try to continue the latest session for the current directory first. If that fails, start a new one.

Zsh:

zsh

codex() {  local base_args="--dangerously-bypass-approvals-and-sandbox"
  command codex ${=base_args} resume --last "$@" 2>/dev/null || command codex ${=base_args} "$@"}

codex() {  local base_args="--dangerously-bypass-approvals-and-sandbox"
  command codex ${=base_args} resume --last "$@" 2>/dev/null || command codex ${=base_args} "$@"}

PowerShell:

powershell

function codex {    $baseArgs = @("--dangerously-bypass-approvals-and-sandbox")    $codexPath = (Get-Command codex -CommandType Application | Select-Object -First 1).Source
    & $codexPath @baseArgs resume --last @args 2>$null
    if ($LASTEXITCODE -ne 0) {        & $codexPath @baseArgs @args    }}

function codex {    $baseArgs = @("--dangerously-bypass-approvals-and-sandbox")    $codexPath = (Get-Command codex -CommandType Application | Select-Object -First 1).Source
    & $codexPath @baseArgs resume --last @args 2>$null
    if ($LASTEXITCODE -ne 0) {        & $codexPath @baseArgs @args    }}

Usage#

Common commands:

# Continue the most recent interactive session for the current directorycodex resume --last
# Skip approvals and sandbox entirely, extremely dangerouscodex --dangerously-bypass-approvals-and-sandbox

# Continue the most recent interactive session for the current directorycodex resume --last
# Skip approvals and sandbox entirely, extremely dangerouscodex --dangerously-bypass-approvals-and-sandbox

codex resume --last filters sessions by the current working directory by default. Run it inside a project to continue that project's latest session. Codex does not resume automatically when you cd into a directory. To resume first and fall back to a new session, use a shell function.