GPT-5.1 Codex vs Grok 4

1. Purpose-Built for Agentic Coding

• Designed specifically for environments where the model acts as an autonomous or semi-autonomous coding agent.
• Optimized for multi-step reasoning in code tasks such as planning, refactoring, debugging, file generation, and tool coordination.

2. Enhanced Coding Intelligence

• Extends GPT-5.1's advanced reasoning capabilities to handle complex software architecture decisions.
• Better accuracy in code generation across languages (JavaScript, Python, TypeScript, Go, Rust, etc.).
• Produces cleaner, more idiomatic code aligned with modern frameworks and best practices.

3. Superior Tool Use & Code Navigation

• Excels at reading, understanding, and transforming multi-file codebases.
• Works well with Codex workflows that simulate real developer tooling.
• Strong at following function signatures, constraints, and code patterns within an existing project.

4. Long-Range Context Awareness

• 400,000-token context window enables the model to ingest large repositories or multiple files simultaneously.
• Supports deep analysis of project structures, dependencies, and cross-file logic.

5. Multi-Modal Development Capabilities

• Accepts text + image input and output - suitable for tasks like:
  • Reading UI mockups or screenshots to generate code
  • Understanding architectural diagrams
  • Reviewing images of whiteboard sessions

6. Agentic Workflow Optimization

• Built to manage longer chains of thought and execution typically required in:
  • Automated code repair
  • Project bootstrapping
  • Linting and migration tasks
  • Long-running coding agents using planning + execution loops

7. Continually Updated Model Snapshot

• Codex-specific version receives regular upgrades behind the scenes.
• Ensures the latest coding improvements without requiring developers to update model names.

8. Reliable Instruction Following

• Highly consistent in honoring explicit constraints:
  • Code styles
  • Folder structures
  • API contracts
  • Framework conventions

9. Broad API Support

• Works across Chat Completions, Responses API, Realtime, Assistants, and more.
• Ideal for apps that need live, reasoning-heavy coding agents or generative dev environments.

1. Flagship-level reasoning and math performance

• Designed for world-class reasoning depth, precision, and multi-step logical chains.
• Excels at STEM, mathematics, symbolic operations, proofs, and analytical workloads.

2. Powerful multimodal understanding

• Supports text, images, and other modalities.
• Handles cross-modal reasoning tasks requiring context synthesis.

3. Extreme capability across diverse tasks

• Positioned as a top-tier 'jack of all trades' model.
• Strong in natural language, coding, knowledge retrieval, and structured generation.

4. Large 256K context window

• Enables analysis of long documents, entire codebases, multi-document packs, and extensive agent sessions.
• Supports workloads that require persistent reasoning across large inputs.

5. Advanced developer tooling support

• Function calling for tool-augmented workflows.
• Structured outputs for predictable, schema-controlled generation.
• Integrates smoothly with agents and complex automation pipelines.

6. Efficient caching for cost reduction

• Cached input tokens discounted to $0.75 / 1M tokens.
• Encourages RAG, retrieval pipelines, and multi-step conversational workflows.

7. Production-ready performance

• Stable rate limits: 480 requests per minute.
• High token throughput: 2,000,000 tokens per minute.
• Available across multiple xAI regional clusters.

8. Optional Live Search augmentation

• Add-on: $25 per 1K sources.
• Enhances factual accuracy and real-time information retrieval.