Codex CLI Specifics

What's the Codex CLI Base URL format?

The Codex Base URL needs the /v1 suffix, unlike Claude Code:

Claude Code: https://your-request-address      (without /v1)
Codex CLI  : https://your-request-address/v1   (with /v1)

Where are Codex CLI config files? How to configure manually?

Two config files:

• ~/.codex/config.toml (Windows: C:\Users\<name>\.codex\config.toml)
• ~/.codex/auth.json (Windows: C:\Users\<name>\.codex\auth.json)

config.toml example:

model_provider = "custom"
model = "gpt-5.4"
model_reasoning_effort = "high"
disable_response_storage = true

[model_providers.custom]
name = "custom"
base_url = "https://your-request-address/v1"
wire_api = "responses"
requires_openai_auth = true
model_context_window = 1000000
model_auto_compact_token_limit = 900000

auth.json example:

{
  "OPENAI_API_KEY": "sk-***"
}

How to enable 1M context in Codex CLI?

Confirm these two in ~/.codex/config.toml:

model_context_window = 1000000
model_auto_compact_token_limit = 900000

• model_context_window: set the usable context window to 1,000,000
• model_auto_compact_token_limit: trigger compaction before the limit to avoid hitting the ceiling

Codex CLI reasoning is slow — what to do?

Change model_reasoning_effort in config.toml from high to medium or low:

• low: fast, for simple code generation and quick Q&A
• medium: medium, for daily development (recommended)
• high: slow, for complex algorithms and architecture design

Codex CLI API Key invalid?

1. Check the Key in ~/.codex/auth.json
2. Confirm the proxy site has sufficient balance and the token hasn't expired

Codex error — 401 Unauthorized: Invalid token

Symptom: Codex CLI errors with unexpected status 401 Unauthorized: Invalid token.

Cause: a previous login overwrote ~/.codex/auth.json, so the Key inside is no longer your proxy API Key.

Fix: manually open ~/.codex/auth.json (Windows: C:\Users\<name>\.codex\auth.json) and set its content to your proxy API Key:

{
  "OPENAI_API_KEY": "sk-***"
}

Save and restart Codex.

Will using Claude Code and Codex CLI together conflict?

No. Their config files are independent and don't conflict. CC Switch can manage both:

• Claude Code → ~/.claude/settings.json
• Codex CLI → ~/.codex/config.toml + ~/.codex/auth.json

Codex error — Image generation is not enabled for this group

Symptom: Codex CLI errors with Image generation is not enabled for this group.

Cause: the current group doesn't have image generation enabled, but Codex tries to carry the image-generation feature by default, so the request is rejected.

Fix: open ~/.codex/config.toml (Windows: C:\Users\<name>\.codex\config.toml) and add under [features]:

[features]
image_generation = false

If there's no [features] section, add it first. Note: Codex has no hot reload — after saving, fully quit and restart Codex for it to take effect.