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.
leanstral-1-5@eu by misc is currently listed from a single provider. Its reference price is $0 per 1M tokens. It also has 1 free ($0) channel; free tiers usually carry rate limits, and subscription-covered access bills $0 per token only after the subscription fee.
The context window is 262,144 tokens, with an output limit of 32,768 tokens. It supports tool use and structured output.
| Provider | Tier | Input | Output | Cache read | Cache write | Context | Output limit | Status |
|---|---|---|---|---|---|---|---|---|
| Requesty leanstral-1-5@eu | Gateway | Free | — | — | 262,144 | 32,768 |
Sorted by blended price (input×0.75 + output×0.25) asc. The official channel always shows regardless of rank. Whether a gateway's low price is actually usable can't be verified.
This model is $0 across all listed channels (Requesty).
Price history accumulates from each data sync; currently only 1 sample(s) (2026-08-19). Each future sync adds a point, and once accumulated a line is drawn here.