Model limit probe

OpenAI: GPT-5.3-Codex | max output limit

OpenAI: GPT-5.3-Codex max output limit decides whether a key can enter a production route. TestKey reads model ID openai/gpt-5.3-codex, provider OpenAI, catalog context, real-key headers, 429 errors, and region signals together.

Model

openai/gpt-5.3-codex

OpenAI: GPT-5.3-Codex

Provider

OpenAI

62 models in catalog

Limit dimension

max output limit

max-output

Visible signal

catalog visible

Context window: 400,000

Limit matrix summary

Model

openai/gpt-5.3-codex

Limit dimension

max-output

Visible signal

catalog visible

Read-only check. Detection data burns after 5 minutes.

Why this limit matters

OpenAI: GPT-5.3-Codex max output limit decides whether a key can enter a production route. TestKey reads model ID openai/gpt-5.3-codex, provider OpenAI, catalog context, real-key headers, 429 errors, and region signals together.

Model: openai/gpt-5.3-codex
Provider: OpenAI
Limit dimension: max output limit

How to prove it

Read-only check. Detection data burns after 5 minutes.

Start with the visible signal: catalog visible, then read headers and error bodies with read-only requests.
max output limit must bind model ID openai/gpt-5.3-codex; limits from another model at the same provider cannot be reused.
max output limit · catalog visible · 400,000

Operator action

OpenAI: GPT-5.3-Codex max output limit is not just a number. It should become route throttling, sale tags, headroom alerts, fallback model suggestions, and price protection.

Read-only check. Detection data burns after 5 minutes.
Visible signal: catalog visible
Context window: 400,000

Open key checker

Read-only check. Detection data burns after 5 minutes.

Open models

OpenAI: GPT-5.3-Codex

Open providers

OpenAI