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Overview

Codex CLI Interface Codex CLI is OpenAI’s official command-line tool for code-related tasks in the terminal. Compared to general chat tools, it emphasizes engineering-ready output with clearer, actionable code changes. By integrating Codex CLI with EvoLink API, you can access EvoLink’s models (such as GPT series) through a unified OpenAI-compatible interface with one key and one base URL.

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Prerequisites

Before configuring, make sure you have:

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1. Install Node.js and npm

Why needed? Node.js is the runtime environment for CLI tools (like installing WeChat on your phone to chat, you need to install Node.js on your computer to run CLI tools). If already installed: Run node -v and npm -v to check version. If v20+, skip this step. First-time installation: 
node -v
npm -v
Node.js and npm version verification
  • Log in to EvoLink Dashboard
  • Find API Keys in the dashboard, click ‘Create New Key’ button, then copy the generated Key
  • API Key usually starts with sk-

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How to Open Terminal

  • Method 1: Press Win + R, type cmd or powershell, then press Enter
  • Method 2: Search for “Command Prompt” or “PowerShell” in the Start menu
  • Method 3: Hold Shift and right-click in a folder, select “Open PowerShell window here”

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Step 1: Install Codex CLI

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1. Global Installation

npm install -g @openai/codex
Expected result: Download info scrolling, ending with added XX packages (takes 1-3 minutes). If error occurs: permission denied means Windows needs “Run as administrator” PowerShell, macOS/Linux add sudo before command.

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2. Verify Installation

codex --version
Success indicator: Shows version number (e.g., 1.x.x). Codex CLI Version Codex CLI supports a custom Provider via config file, no source code modification needed.

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1. Open Config Directory

Press Win + R, paste the following, then press Enter to open the Codex config directory:
%userprofile%\.codex
Windows Win+R open config directory
Codex CLI config environment

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2. Edit config.toml

Find the config.toml file in the config directory and edit it with the following content:
model = "gpt-5.2"
model_reasoning_effort = "medium"
model_provider = "evolink"

[model_providers.evolink]
name = "EvoLink API"
base_url = "https://code.evolink.ai/v1"
env_key = "OPENAI_API_KEY"
wire_api = "responses"
⚠️ Important:
  • Copy completely without missing any symbols
  • Replace "your-evolink-api-key" with actual API Key
  • TOML format is sensitive to indentation and symbols
model = "gpt-5.2"
model_reasoning_effort = "medium"
model_provider = "evolink"

[model_providers.evolink]
name = "EvoLink API"
base_url = "https://code.evolink.ai/v1"
env_key = "OPENAI_API_KEY"
wire_api = "responses"
Config fields:
  • model: default model name
  • model_reasoning_effort: reasoning depth (adjust as needed)
  • model_provider: provider name that matches the section below
  • base_url: EvoLink API endpoint
  • env_key: environment variable name for the API key
  • wire_api: must be responses

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2. Configure API Key

Temporary (current session only)
$env:OPENAI_API_KEY = "your-evolink-api-key"
Permanent
[Environment]::SetEnvironmentVariable("OPENAI_API_KEY", "your-evolink-api-key", "User")
Restart the terminal for changes to take effect.Verify Configuration
echo $env:OPENAI_API_KEY
Check if environment variable is added successfullyIf it outputs your API Key, the configuration is successful.

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Step 3: Start Using Codex CLI

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1. Enter working directory

cd <your-working-directory>
Note: Replace <your-working-directory> with actual path

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2. Interactive mode

codex
Codex CLI Interface

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3. Verify configuration

codex "Who are you"
Success indicators:
  • See AI response text (several lines)
  • No errors like 401, 403, API Key invalid
If you see errors:
  • 401 Unauthorized: API Key not set or invalid → Check environment variable
  • 403 Forbidden: Insufficient API Key permissions → Verify API Key
  • Network error: Network issue → Check connection

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FAQ

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1. What is Codex CLI and what is it used for?

Codex CLI is OpenAI’s official command-line tool focused on code-related tasks. It emphasizes engineering-ready output with clearer, actionable code changes.

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2. How do I verify installation and configuration on first use?

Run these commands in sequence:
  • node -v and npm -v: Confirm Node.js and npm are installed
  • codex --version: Confirm Codex CLI is installed
  • codex "Who are you": Confirm API configuration is correct

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3. What’s the difference between interactive mode and single command mode?

  • Interactive mode: Run codex to enter continuous conversation for multi-turn interactions
  • Single command mode: Run codex "question" to get a single response and exit

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4. Will Codex CLI automatically read or upload my local files and code?

No. Codex CLI only reads file content when you explicitly reference or authorize it. It’s recommended to use it in a dedicated project folder.

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5. How do I use Codex CLI to analyze local file content?

In interactive mode, you can reference files by:
  • Typing the file path for Codex to read
  • Dragging files into the terminal window
  • Copy and pasting file content

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6. Does Codex CLI support Chinese input and output?

Yes, fully supported.

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7. No output after execution—what could be the cause?

Common causes include:
  • Network connection issues
  • Invalid API Key or insufficient balance
  • Incorrect base_url configuration
  • Firewall or proxy blocking requests

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8. Why don’t my config changes take effect?

  • Restart your terminal
  • Check config.toml syntax (TOML format)
  • Verify config file path:
    • Windows: C:\Users\{username}\.codex\config.toml
    • macOS / Linux: ~/.codex/config.toml

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9. What causes 401/403 errors?

  • 401 error: OPENAI_API_KEY not set or invalid
  • 403 error: Insufficient permissions or expired key
  • Check that env_key matches your environment variable name

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10. What scenarios is Codex CLI suited for?

Suited for:
  • Code writing, debugging, and refactoring
  • Quick Q&A in command-line environments
  • File content analysis
Not suited for:
  • Complex GUI interactions
  • Real-time collaborative editing

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11. How do I switch models?

Open the configuration file config.toml (located at ~/.codex/config.toml or C:\Users\{username}\.codex\config.toml), and modify the model field: 
model = "gpt-5.2"  # Change to your desired model name
Save the file and restart Codex CLI for changes to take effect.

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12. How do I upload images?

  • Option 1: Reference the image path
  • Option 2: Drag and drop an image into the terminal
  • Option 3: Paste an image directly
All methods require user action—Codex CLI will not automatically read or upload local images.

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Notes

Run Codex CLI in a dedicated project folder. Avoid running it in sensitive directories (such as system folders or directories containing credentials). Codex CLI operates starting from the current working directory.
The wire_api in config must be set to "responses". "chat" is deprecated.