Shanghai AI Lab / internlm/intern-s2-free
Intern-S2 - access through LLMTR
Intern-S2 (书生-S2) is Shanghai AI Lab's multimodal foundation model for scientific reasoning and long-horizon agent tasks. It was trained by reading scientific papers together with their figures and refined with reinforcement learning across more than twenty scientific domains, so it can answer questions that depend on figures, charts and tables in an image. Its context window is 262,144 tokens and it accepts text and images (URL or base64). Tool calling is supported; use auto for tool_choice. response_format (JSON mode) is not supported, so ask for JSON in the prompt when you need it. The model reasons before answering by default and the reasoning text arrives in reasoning_content; to turn reasoning off, send "reasoning": false or add :fast to the model id. Reasoning tokens count toward max_tokens, so a short max_tokens can cut the answer off before reasoning ends. It is free until 31 October 2026, 23:59 (TRT), with 500,000 tokens per person per day (input and output together).
Technical specifications
| Canonical ID | internlm/intern-s2-free |
|---|---|
| Provider | Shanghai AI Lab |
| Context window | 262,144 tokens |
| Operations | CHAT_COMPLETIONS |
| Modalities | text, image |
Pricing
An 8% platform margin applies to credit top-ups; model usage prices are not separately marked up.
| Operation | Metric | Unit | Price |
|---|---|---|---|
| CHAT_COMPLETIONS | INPUT_TEXT | PER_1M_TOKENS | Not available |
| CHAT_COMPLETIONS | OUTPUT_TEXT | PER_1M_TOKENS | Not available |
Example usage
With existing OpenAI SDK flows, change only the base URL and model identifier.
curl https://llmtr.com/v1/chat/completions -H "Authorization: Bearer llmtr-your_key" -H "Content-Type: application/json" -d '{"model":"internlm/intern-s2-free","messages":[{"role":"user","content":"Hello"}]}'Guides about this model
- Shanghai AI Lab models: Intern-S2 to Sage-A1.5 compared - Shanghai AI Lab's five models are called on LLMTR with the same API key through /v1/chat/completions and are free until 31 October 2026, 23:59 (TRT). Intern-S2 is for scientific questions with images, Atria-Dawn for long text-based agent work, Atria-Dawn Preview for trying the open release, Agents-A1 for tool agents that read images, and Sage-A1.5 for flows with subagents. From 1 November 2026 all five return 410.
- Reading scientific charts and tables with the Intern-S2 API - On LLMTR, Intern-S2 is called with the model id internlm/intern-s2-free at https://llmtr.com/v1/chat/completions with the OpenAI SDK, accepts images alongside text and is free until 31 October 2026, 23:59 (TRT). Send the image of a scientific figure or table as a base64 data URL and ask for the rows as JSON in the prompt; response_format is not supported on this row. The allowance is 500,000 tokens a day per model; new accounts start with a smaller allowance on their first day.
- Atria-Dawn vs Atria-Dawn Preview: stable release or open preview - Both rows are called on LLMTR with the same API key through /v1/chat/completions; they offer a 524,288-token context, text-only input, json_schema and tool calling, and they are free until 31 October 2026, 23:59 (TRT). Atria-Dawn is the stable release; Atria-Dawn Preview is the preview whose weights are open under the MIT license.
- Reasoning and the daily token allowance on Shanghai AI Lab models - All five rows reason before answering by default, and reasoning tokens count toward both max_tokens and the daily token allowance. To turn reasoning off, send "reasoning": false or add :fast to the model id; reasoning_effort returns 400. The rows are free until 31 October 2026, 23:59 (TRT).
- Long-document extraction with Atria-Dawn and JSON Schema - Atria-Dawn can read a long document in one request and return fields that follow a strict JSON Schema, and it is free until 31 October 2026, 23:59 (TRT). Input, output and reasoning share the same context window and the same daily allowance; turning reasoning off for extraction saves tokens.
- Intern-S2 vs Qwen3.8 27B, Nemotron 3.5 Super VL, Agnes 2.5 Flash - All four models read images on LLMTR with the same API key through /v1/chat/completions. Intern-S2 is free until 31 October 2026, 23:59 (TRT) and returns 410 from 1 November 2026; Qwen3.8 27B, Nemotron 3.5 Super VL and Agnes 2.5 Flash run on quotas with no end date set and can be used free of charge after 31 October 2026 as well. Video is open only on Nemotron 3.5 Super VL and Agnes 2.5 Flash; Agnes takes images only as base64 data URLs.
- Shanghai AI Lab models after 1 November 2026: migration guide - The five Shanghai AI Lab models are free until 31 October 2026, 23:59 (TRT); from 1 November 2026, 00:00, they return 410 model_retired and are not redirected. Scientific questions with images and image-reading agents move to Nemotron 3.5 Super VL or Qwen3.6 35B-A3B; long text-based agent work moves to Nemotron 3 Ultra, Agnes 2.5 Flash, DeepSeek V4.1 Flash or MiniMax M3.1 Flash.
Related models
- Atria-Dawn internlm/atria-dawn-free
- Atria-Dawn Preview internlm/atria-dawn-preview-free
- Agents-A1 internlm/agents-a1-free
- Sage-A1.5 internlm/sage-a1.5-free
- Gemma 4 llmtr/gemma-4
- Qwen 3.6 35B-A3B llmtr/qwen3-6-35b
- Qwen 3.8 27B llmtr/qwen3-8-27b
- Trendyol Asure 12B llmtr/trendyol-asure-12b