Configure OpenAI Codex CLI to use DeepSeek models

codex-deepseek-setup.md

Configure OpenAI Codex CLI for DeepSeek

Two files needed to make DeepSeek work properly with Codex CLI:

1. ~/.codex/config.toml

model = "deepseek-reasoner"
model_provider = "deepseek-reasoner"
approval_policy = "on-failure"
sandbox_mode = "workspace-write"
project_doc_max_bytes = 32768

[model_providers.deepseek-reasoner]
name = "DeepSeek Reasoner"
base_url = "https://api.deepseek.com/v1"
env_key = "DEEPSEEK_API_KEY"
wire_api = "chat"
request_max_retries = 3
stream_max_retries = 5
stream_idle_timeout_ms = 180000

[model_providers.deepseek-chat]
name = "DeepSeek Chat"
base_url = "https://api.deepseek.com/v1"
env_key = "DEEPSEEK_API_KEY"
wire_api = "chat"
request_max_retries = 4
stream_max_retries = 8
stream_idle_timeout_ms = 120000

[profiles.deepseek-reasoner]
model = "deepseek-reasoner"
model_provider = "deepseek-reasoner"
approval_policy = "on-failure"
sandbox_mode = "workspace-write"
model_supports_reasoning_summaries = false

[profiles.deepseek-chat]
model = "deepseek-chat"
model_provider = "deepseek-chat"
approval_policy = "on-failure"
sandbox_mode = "workspace-write"
model_supports_reasoning_summaries = false

[sandbox_workspace_write]
exclude_tmpdir_env_var = false
exclude_slash_tmp = false
network_access = true

[shell_environment_policy]
inherit = "all"
ignore_default_excludes = false

[history]
persistence = "save-all"

2. ~/.codex/AGENTS.md

# Agent Instructions for Codex CLI

## DeepSeek Models Critical Instructions

### IF YOU ARE A DEEPSEEK MODEL:

**CRITICAL**: DeepSeek models MUST use the shell function for ALL command execution.

#### Shell Command Execution
- **ALWAYS** use the `shell` function to execute commands
- **NEVER** call commands directly
- Syntax: `shell(cmd=["bash", "-lc", "command"], workdir="path")`

Examples:
- List files: `shell(cmd=["bash", "-lc", "ls -la"], workdir=".")`
- Read file: `shell(cmd=["bash", "-lc", "cat filename"], workdir=".")`
- Search: `shell(cmd=["bash", "-lc", "rg 'pattern'"], workdir=".")`

#### File Operations
- Use provided file operation tools when available (read_file, write_file)
- Otherwise use shell commands through the shell function

### Working Directory
- Always set the `workdir` parameter when using shell function
- Use absolute paths or specify workdir instead of `cd`

### For All Models
- Respect sandbox mode settings
- Follow approval policy
- Handle errors gracefully

Setup

1. Set API key:

export DEEPSEEK_API_KEY="your-key"

2. Place config.toml in ~/.codex/config.toml
3. Place AGENTS.md in ~/.codex/AGENTS.md