GPT 5.3 Codex
GitHub Copilot responsesGPT 5.3 Codex is a GitHub Copilot responses-API model.It supports a 128,000-token context windowwith up to 128,000 output tokens. Capabilities include function calling, vision. Route GPT 5.3 Codex via Future AGI's Agent Command Center for unified observability, caching, and 15 routing strategies including cost-optimized fallback.
We don't have verified per-token pricing for GPT 5.3 Codex yet. If you have a source from GitHub Copilot's documentation, help us add it — your submission gets reviewed within 48 hours.
Pricing
Per-token rates, expressed in USD per 1M tokens. Verified May 12, 2026.
| Input | — | |
| Output | — |
Limits
- Context window
- 128,000 tokens
- Max input
- 128,000 tokens
- Max output
- 128,000 tokens
- Modalities
- vision, text
Capabilities
- Function calling ✓ supported
- Parallel tool calls ✓ supported
- Vision input ✓ supported
- Audio input — not advertised
- Audio output — not advertised
- PDF input — not advertised
- Streaming ✓ supported
- Structured output ✓ supported
- Prompt caching — not advertised
- Reasoning — not advertised
Where it's strong
- +long-form generation — 128,000-token max output, top-4% of peers
Watch out for
- !limited context — 128,000-token window is in the bottom quartile; not ideal for long documents or large RAG
Benchmarks pending
We haven't logged public benchmark scores for GPT 5.3 Codex yet. Have one to contribute? Submit a source — citations help us prioritise.
Call GPT 5.3 Codex via Agent Command Center
One OpenAI-compatible endpoint. Routing, fallback, semantic caching, guardrails, and cost tracking come along for the ride. First 100K requests + 100K cache hits free every month.
agentcc / @agentcc/client). Per-call metadata — provider, cost, latency, cache hit, request id — is returned on x-agentcc-* response headers, so any HTTP client can read it.# GPT 5.3 Codex via the Agent Command Center Python SDK
# pip install agentcc
import os
from agentcc import AgentCC
client = AgentCC(
api_key=os.environ["AGENTCC_API_KEY"], # from app.futureagi.com → Settings → API Keys
base_url="https://gateway.futureagi.com/v1",
)
resp = client.chat.completions.create(
model="github-copilot/gpt-5-3-codex",
messages=[{"role": "user", "content": "Hello, GPT 5.3 Codex!"}],
)
print(resp.choices[0].message.content)
print(f"Tokens: {resp.usage.total_tokens}")
# Per-call gateway metadata is returned on x-agentcc-* response headers.
# When you need it programmatically, use .with_raw_response to get them:
raw = client.chat.completions.with_raw_response.create(
model="github-copilot/gpt-5-3-codex",
messages=[{"role": "user", "content": "Same call, but I want the headers."}],
)
print("Provider:", raw.headers.get("x-agentcc-provider"))
print("Latency:", raw.headers.get("x-agentcc-latency-ms"), "ms")
print("Cost: ", raw.headers.get("x-agentcc-cost"), "USD")
print("Cache: ", raw.headers.get("x-agentcc-cache"))AGENTCC_API_KEY with a key fromapp.futureagi.com.Gateway docs ↗Same model on other providers
gpt-5-3-codex is also available via 2 other routes. Pricing, regions, and capabilities can differ — compare before routing production traffic.
| Provider | Input / 1M | Output / 1M | Verified |
|---|---|---|---|
| Azure OpenAI | $1.75/M | $14.00/M | May 12, 2026 |
| OpenAI | $1.75/M | $14.00/M | May 12, 2026 |
Compare with similar models
GPT 5.3 Codex doesn't have a public Arena ELO score yet, so we group by provider only — quality-tier comparisons need a benchmark.
FAQ
How much does GPT 5.3 Codex cost?
Public per-token pricing for GPT 5.3 Codex is not yet published. Submit a source on this page to help us add it.
What is the context window of GPT 5.3 Codex?
GPT 5.3 Codex supports a 128,000-token context window with up to 128,000 output tokens.
Does GPT 5.3 Codex support function calling?
Yes — GPT 5.3 Codex supports function (tool) calling, including parallel tool calls.
Is GPT 5.3 Codex good for production?
GPT 5.3 Codex is well-suited for long-form generation — 128,000-token max output, top-4% of peers. Consider alternatives if you need limited context — 128,000-token window is in the bottom quartile; not ideal for long documents or large RAG.
How can I route to GPT 5.3 Codex with fallback?
Use Agent Command Center: a single OpenAI-compatible endpoint that supports cost-optimized routing, latency-aware retries, model fallback, and shadow traffic. Configure once, swap models without app changes.
Useful links for GPT 5.3 Codex
Official sources, independent benchmarks, and pricing aggregators — no random search-engine guesses.
Third-party evals — verify the marketing.
Cross-check our number against the rest of the ecosystem.