GPT-5

GPT-5 is OpenAI’s latest flagship language model, presented as a unified, multimodal reasoning system that improves on prior generations in reasoning, coding, long-context understanding, and safety-aware outputs. It combines fast non-reasoning components with a deeper reasoning model and a real-time router that selects the best submodel for a task, enabling the system to “know when to think.”

Basic Features

• *Multimodality & tooling:*: GPT-5 accepts text and images (and is designed to work with external tools and browsing/agents where allowed), and OpenAI highlights improved voice, UI, integrated connectors (e.g., Gmail/Calendar) and agentic workflows.
• Expanded Context Window: Supports up to 1,000,000 tokens, allowing for far longer documents, codebases, or conversation histories .
• Context & limits: 400K token total context window (split implicitly between input and output, with typical splits such as ~272K input + 128K output )

Technical Architecture

GPT-5 is a unified system composed of:

1. A fast non-reasoning model for routine queries.
2. A deep reasoning variant (“GPT-5 Thinking”) for complex problems.
3. A real-time router that dynamically selects the optimal pathway based on prompt complexity, tool requirements, and user intent .

This design leverages parallel test-time compute for GPT-5 Pro, ensuring high-stakes tasks receive the most comprehensive processing available.

Benchmark Performance

• Coding: Achieves 74.9% on SWE-Bench Verified, surpassing prior models by over 5 percentage points and using 22% fewer tokens and 45% fewer tool calls than its predecessor.
• Health: Scores 46.2% on HealthBench Hard, demonstrating significant gains in medical reasoning and patient-focused guidance.
• Factuality: Approximately 80% fewer hallucinations in “thinking” mode compared to OpenAI o3, and 45% fewer factual errors in standard chat mode relative to GPT-4o .
• Multimodal: Excels at analyzing text, images, and video inputs, enhancing visual reasoning and perception.
• Writing: Captures literary rhythm and nuanced structures like free verse or iambic lines more reliably

---

Model Versions

---

Limitations

• Not AGI: While a leap forward, GPT-5 still lacks continuous learning and self-improvement outside of retraining cycles .
• Remaining Hallucinations: Despite reduction, verified sources are recommended for critical decisions.
• Compute & Cost: High-performance modes (Pro, Thinking) incur significant token fees and require careful budget management.

How do I start using the gpt-5 API?

Required Steps

• Log in to cometapi.com. If you are not our user yet, please register first
• Get the access credential API key of the interface. Click “Add Token” at the API token in the personal center, get the token key: sk-xxxxx and submit.
• Get the url of this site: https://api.cometapi.com/

Use Method

1. Select the “gpt-5”endpoint to send the API request and set the request body. The request method and request body are obtained from our website API doc. Our website also provides Apifox test for your convenience.
2. Replace <YOUR_API_KEY> with your actual CometAPI key from your account.
3. Insert your question or request into the content field—this is what the model will respond to.
4. . Process the API response to get the generated answer.

CometAPI provides a fully compatible REST API—for seamless migration. Key details to API doc:

• Core Parameters: prompt, max_tokens_to_sample, temperature, stop_sequences
• Endpoint: https://api.cometapi.com/v1/responses
• Model Parameter: “gpt-5”
• Authentication: Bearer YOUR_CometAPI_API_KEY
• Content-Type: application/json .

API Call Instructions: gpt-5-chat-latest should be called using the standard /v1/chat/completions format. For other models (gpt-5, gpt-5-mini, gpt-5-nano, and their dated versions), using the /v1/responses format is recommended. Currently two modes are available.