Llmll

Llmll is a programming language and verification pipeline letting AI agents write code under formal contracts.

LLMLL is a programming language and verification pipeline built for experiments in which AI agents write code under formal contracts. Its primary author is an LLM agent, which fills typed holes while the compiler proves each body against its contract with Z3 before the patch is applied. Agents coordinate through contracts rather than conversation, turning hallucination into a search strategy. Every program has a JSON-AST form, and patches are JSON-Patch against it to prevent merge conflicts. It supports SMT over a non-recursive QF-LIA core, array classes, admissible datatype construction, and string literals, with optional Lean theorem integration.

Llmll at a glance

Best for: Software engineer, Researcher
Runs on: CLI, self-hosted, open source
Pricing: Free
Released: October 2026
Category: AI coding tool
Website: github.com/machunter/llmll

Key features

Compiler verification against contracts using Z3
JSON-AST structured patches without text merge conflicts
Weakness checker to flag excessively weak contracts
Trust level tracking for verified and asserted functions
Refinement spawning contracted sub-holes
Lean theorem verification integration

Use it for

AI agents writing verified code under formal contracts
Proving function bodies against contracts with SMT solvers
Managing agent coordination through contracts
Checking contract strength and non-vacuity

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