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OpenAI model

GPT 5.3 Codex

GPT 5.3 Codex in the public OpenAI catalog.

Provider
OpenAI
Availability
Available
Model ID
gpt-5.3-codex
Snapshot
2026-10-07
Evaluation Verdict

OpenAI GPT-5.3 Codex Spark provides ultra-responsive code generation (75.0% SWE-bench Verified, 1438 Coding Elo), blending speed with frontier reasoning for real-time agent pair programming.

GPT 5.3 Codex Benchmarks & Agentic Accuracy

Verified primary research & developer preference metrics

Primary Sources Verified
SWE-bench Verified
75%
Fast Autonomous ModeCodex Technical Report ↗
LiveCodeBench
78.6%
ThinkingLiveCodeBench ↗
LMSYS Coding Elo
1438Elo
Coding ArenaLMSYS Arena ↗
AIME 2024 / 2025
94.2%
ThinkingCodex Technical Report ↗
Pricing ($ / 1M tokens)
$2.5/ $10
$0.45 cached readStandard API Pricing

What This Means in Real Software Development

  • 75.0% on SWE-bench Verified with rapid execution.
  • Optimized for real-time terminal interactions, shell command generation, and fast build troubleshooting.
  • Near-zero first-token latency (<300ms TTFT) makes it feel instantaneous in the Swarm TUI.
  • Highly stable for automated test repair loops and continuous integration pipelines.

Swarm Multi-Agent Topology

Tier 1: High-Speed Frontier CoderRole: Coder Subagent

Best Paired With: Claude 3.7 Sonnet as Lead Planner

High throughput and elite coding logic make it ideal for rapid iterative development cycles.

Git Worktree Isolation Advantage:

Executes rapid code edits and commits to isolated Git worktrees without blocking the user.

What Developers & Practitioners Are Saying

Real-world field observations, production strengths, and developer consensus

Field Consensus

"Ultra-responsive Codex variant tailored for instant completions and rapid subagent triage."

Verified Real-World Strengths

  • High throughput
  • Instant start-up time for fast terminal command validation
  • Affordable token economics

Production Caveats & Gaps

  • Less suitable for deep architectural system planning
Benchmark Reality Check

What the benchmark tests: Evaluates rapid code completion and localized error patching.

Production caveat: Best assigned as a Coder or Validator subagent under a primary planner.

Primary Sources & Methodology Citations

GPT 5.3 Codex model overview

GPT 5.3 Codex is listed in the public Swarm catalog through OpenAI. This page summarizes the verified catalog fields used by Swarm without claiming real-time access for every provider account.

Provider
OpenAI
Family
Gpt 5
Context window
400K tokens
Thinking support
Not supported
Availability status
Available
Catalog ID
openai/gpt-5.3-codex
  • File input
  • Image input
  • Text input
  • Text output
  • Reasoning
  • Tools
  • Structured output
  • JSON

Run GPT 5.3 Codex in Swarm

Verified CLI workflow & multi-agent architecture

Quickstart Guide →
bash — swarm run
$swarm ctl model set --provider openai --model openai/gpt-5.3-codex

# Or switch interactively inside the terminal TUI:

>/models

Subagent Role Matrix

Assign GPT 5.3 Codex to specialized system roles in ~/.swarm/config.json:

  • Primary / Planner: Orchestrates full task DAGs and multi-stage pipelines.
  • Coder Subagent: Generates code and unit tests inside private Git worktrees.
  • Finder Subagent: Performs read-only code search, symbol discovery, and mapping.
System Agent Roles →Why Swarm Architecture →
← All OpenAI models

Public catalog snapshot. Catalog availability is not a real-time provider status or an access guarantee.