OpenAI: GPT-4o (2024-11-20)

Generates natural language text across diverse domains using a transformer-based architecture trained on diverse internet text and proprietary datasets. The 2024-11-20 version incorporates improved instruction-following and creative writing patterns through reinforcement learning from human feedback (RLHF), enabling more contextually relevant and engaging prose with better adherence to stylistic constraints and tone requirements.

Processes images and documents as input through a vision encoder that extracts spatial and semantic features, integrating them with the text transformer backbone to enable joint reasoning over visual and textual content. Supports multiple image formats and can analyze charts, diagrams, screenshots, and photographs with understanding of layout, text within images (OCR), and visual relationships.

Enables the model to request execution of external functions by generating structured JSON payloads conforming to developer-defined schemas. The model learns to map natural language requests to appropriate function calls through training on function definitions, parameter types, and usage examples, supporting parallel function calls and error recovery through multi-turn conversations.

Accepts system-level instructions that define the model's behavior, tone, constraints, and role within a conversation. The system prompt is processed separately from user messages through a specialized attention mechanism that weights system instructions more heavily during token generation, enabling consistent personality and behavioral constraints across multi-turn conversations.

Accepts multiple requests bundled into a single batch file (JSONL format) and processes them asynchronously with lower per-token pricing (50% discount vs. real-time API). Requests are queued and processed during off-peak hours, with results returned via webhook or polling, enabling cost-effective processing of non-time-sensitive workloads at scale.

Maintains a 128,000-token context window that can accommodate approximately 100,000 words of conversation history, documents, or code. The model uses sliding-window attention patterns and efficient tokenization to process long contexts without quadratic memory growth, enabling analysis of entire codebases, long documents, or extended multi-turn conversations within a single request.

Constrains model output to conform to developer-provided JSON schemas, ensuring responses are valid JSON matching specified field types, required properties, and nested structures. The model generates tokens that are guaranteed to produce valid JSON without post-processing, using constrained decoding that prunes invalid token sequences during generation.

Allocates additional computational resources to internal reasoning steps before generating final responses, using a chain-of-thought pattern that explores multiple solution paths and validates reasoning before committing to an answer. This mode trades latency for accuracy on complex reasoning tasks by enabling the model to 'think through' problems more thoroughly.