Active
leanstral-1-5
Leanstral 1.5 is an updated Lean 4 formal proof engineering model from Mistral AI, optimized for automated theorem proving and autoformalization. It has 119B total parameters with 6.5B active and supports a 256K token context window. It supports native function calling and structured output.
Context
262,144
Max output
32,768
Input / 1M
Not listed
Output / 1M
Not listed
Providers
1
01Profile
Profile
Released
2026-05-27
Last updated
2026-05-27
Knowledge cutoff
—
Weights
Closed
02Capabilities
Capabilities
Input
text
Output
text
Reasoning
No
Tool calling
Yes
Structured output
Yes
Attachments
No
Cache read
—
Cache write
—
03Pricing
Pricing across 0 providers
Per 1M tokens, USD. Sorted by input price. First-party row highlighted.
04History
Change history
2+ recent events since 2026-05-27
2026-08-18Addedrequestyoffering→ new
2026-08-18Addedrequestyoffering→ new