Labs Leanstral 1.5.1

by Mistral

The point release of Mistral's experimental proof engineering line, Labs Leanstral 1.5.1 supersedes the initial Leanstral 1.5 endpoint while keeping its recipe intact, a mixture-of-experts design with 119 billion total parameters, 6.5 billion active per token, and a 256K context window. Like 1.5 it writes and checks Lean 4 proofs, translating informal mathematics into machine-checkable statements and searching for proofs autonomously. As the current revision it carries the refinements accumulated since the June 2026 debut of 1.5, making it the endpoint to reach for when staying on the freshest build of the line matters. The workload profile is unchanged, automated theorem proving, autoformalization, and formal verification of program correctness.

Key info

Input
Output
Features
Context window
262K
Max output
Input price
/1M
Output price
/1M
  • onchain settlement available
  • No training by default
  • no-KYC deposit available

Available routes

Labs Leanstral 1.5.1 runs on 1 route through the qynio gateway. Compare residency, zero retention, and training posture at a glance — full data-handling detail per route below.

ProviderRegionZero data retentionTrainingInputOutput
EUNot by defaultNo

Uptime and availability

Labs Leanstral 1.5.1 runs on a single route through the qynio gateway today, so its availability is that provider's availability.

100%route uptime, last 30 days
Single route, no failover target within this model.

Name a second model in the same request and the gateway tries it on retriable errors, so a busy hour never has to reach your users. .

Measured over the last 30 days from each provider's official status feed via StatusGator. Refreshed hourly. See uptime for every provider qynio monitors.

Data handling per route

Each route hosting Labs Leanstral 1.5.1 has its own privacy posture, residency, and no-KYC terms. Postures are maintained by qynio with a last-verification timestamp.

Mistral France🇫🇷

Zero data retention is not on by default — abuse monitoring, 30-day retention. No training on customer data. EU; deposit available.

Zero data retention
Not by default — abuse monitoring, 30-day retention. Derived from the logging and moderation facts.
Training
No training on customer data.
Logging
Abuse monitoring (30-day retention)
Moderation
Not established
Caching
Not established
Subprocessor access
Not established
no-KYC deposit
deposit available
Transfer mechanism
Not applicable — data stays in EU

Get started

Call Labs Leanstral 1.5.1 through the qynio gateway with one API key. Let your coding agent set it up, or call it directly — qynio is drop-in compatible with the OpenAI, Anthropic, and Google AI SDKs.

Set it up with your agent

Copy this and paste it into a coding agent like Claude Code, Cursor or Codex and it'll wire up qynio for you.

Or call it directly

import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.QYN_API_KEY,
baseURL: "https://api.qyn.io/v3/compat",
});
const completion = await client.chat.completions.create({
model: "mistral/labs-leanstral-1-5-1",
messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

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