Jais 3 vs Mistral AI API

Jais 3

Jais 3 runs on the owner's hardware through OpenAI-compatible servers in vLLM and SGLang, with tool calls, three reasoning levels and a 512K context, from a 2.2 GB 0.9B model to a 758 GB 375B one. The weights download without sign-up under Apache-2.0, but every launch command trusts remote code, and no technical report or security contact is published.

Mistral AI API

Public OpenAPI document at docs.mistral.ai/openapi.yaml and an llms.txt with Markdown twins. Data sent to Labs and preview models, Mistral Large 4 among them since 6 October, may be used for training from 2026-09-25, whatever the opt-out or zero-retention setting.

Jais 3

1. Start vLLM or SGLang with --reasoning-parser k2_horizon, and add --tool-call-parser k2_horizon (vLLM also --enable-auto-tool-choice) for tools, or tool calls come back as raw text
2. Pass reasoning_effort (high, medium or low) and tool_call_format inside chat_template_kwargs. Other values return a template error
3. Send each earlier assistant turn back with reasoning_content as a string, even an empty one. A missing or null thinking field makes the template raise an error
4. Send your own system message, or set default_system_prompt to an empty string. Without one the template inserts an identity prompt naming IFM, Inception42 and Cerebras
5. Budget at least 32,768 output tokens at high effort, which the cards recommend for every request

Mistral AI API

1. Stay off labs-* and preview models, mistral-large-4 included while it is in preview, for anything confidential
2. Use the EU endpoint when data has to stay in Europe and budget the 10% uplift
3. Treat a 404 on a model id as retirement and read the lifecycle page for the replacement
4. Move zai-glm-5-2 calls to zai-glm-5-3 before 31 October 2026. The price is the same
5. Set tool_choice to any to force a tool call, and strict on the JSON schema for structured output