Unable to use Vercel AI Gateway with Codex CLI (429 too many requests)

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1

Problem Description

When using AI Gateway with OpenAI’s Codex CLI, I am unable to get the requests to consistently succeed. The config looks like it started to work, but then I immediately get hit by 429s. I can see my credits go down slightly, so I know that a few requests definitely worked.

See below what the output of codex looks like

╭────────────────────────────────────────────────────────╮
│ >_ OpenAI Codex (v0.39.0)                              │
│                                                        │
│ model:     openai/gpt-5   /model to change             │
│ directory: ~/personal/arishi-monorepo                  │
╰────────────────────────────────────────────────────────╯

  To get started, describe a task or try one of these commands:

  /init - create an AGENTS.md file with instructions for Codex
  /status - show current session configuration
  /approvals - choose what Codex can do without approval
  /model - choose what model and reasoning effort to use

▌ Explain what this repo does?

> I’ll scan the repo structure and README to summarize its purpose.

• Explored
  └ List ls -la
    Read README.md

⚠️ stream error: exceeded retry limit, last status: 429 Too Many Requests; retrying 1/5 in 180ms…

⚠️ stream error: exceeded retry limit, last status: 429 Too Many Requests; retrying 2/5 in 425ms

Steps to reproduce

Create the following config in ~/.codex/config.toml

model = "openai/gpt-5"
model_provider = "vercel-ai-gateway"

[model_providers.openai] # this works just fine
name = "OpenAI"
base_url = "https://api.openai.com/v1"
env_key = "OPENAI_CODEX_API_KEY"
wire_api = "responses"

[model_providers.cloudflare-ai-gateway] # This ALSO works just fine
name = "Cloudflare AI Gateway"
base_url = "CF_AI_GATEWAY_URL (obfuscated for safety)"
env_key = "OPENAI_CODEX_API_KEY"
wire_api = "responses"

[model_providers.vercel-ai-gateway] # this does not work
name = "Vercel AI Gateway"
base_url = "https://ai-gateway.vercel.sh/v1"
env_key = "VERCEL_AI_GATEWAY_API_KEY"
wire_api = "chat"

Then use OpenAIs Codex CLI on any project, and watch the 429s roll in.

3

It looks like it’s retrying repeatedly and then gets rate limited with that 429 response. First thing I’d check is that you have VERCEL_AI_GATEWAY_API_KEY configured correctly. You could also try changing wire_api = "chat" to wire_api = "responses" in your AI Gateway config, since that’s what works for your other providers.

Please give that a try and let me know how it goes

4

Hey @amyegan .

  1. For the wire_api config, Vercel AI Gateway doesn’t actually support the responses API, so I can’t use that config
  2. Yes the API key variable is definitely defined

Again, Vercel gateway is not completely dead, it does respond, but it also returns a lot of 429s, which is very weird.

See this example below, some responses are coming back, but you can see a lot of 429s too.

image
image2932×1602 389 KB

5

I found these issues related to the 429 status code you’re seeing with Codex:

6

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