Vesper Framework

Verified execution bridging traditional code and LLM-native runtimes

Vision

Vesper enables a future where software is developed at the intent level rather than implementation level. It provides:

• Semantic Specification: A high-level, LLM-native way to express software behavior
• Dual-Path Execution: Run the same semantic specification through both proven Python implementations and experimental optimized runtimes
• Gradual Migration: Shift from traditional code to direct execution based on empirical verification
• Verification-First: Prove correctness through differential testing before trusting new implementations

The Problem

Current software development is constrained by human-centric programming languages designed decades ago. As LLMs become capable of understanding intent directly, we need representations optimized for:

1. LLM reasoning - Semantic graphs, contracts, and capabilities rather than imperative code
2. Automatic optimization - Runtimes that can reoptimize based on actual behavior
3. Formal verification - Provable correctness through contracts and properties
4. Evolution - Systems that adapt without manual refactoring

But we can't abandon proven technology. We need a hedged bet: maintain traditional implementations while building toward an LLM-native future.

The Solution

┌─────────────────────────┐
│   Vesper Spec (.vsp)    │  ← Single source of truth
│  Intent + Contracts     │
└────────────┬────────────┘
             │
   ┌─────────┴─────────┐
   │                   │
   ▼                   ▼
┌──────────────┐  ┌──────────────┐
│ Python Path  │  │ Direct Path  │
│  (Proven)    │  │ (Optimized)  │
└──────┬───────┘  └──────┬───────┘
       │                 │
       └────────┬────────┘
                ▼
       ┌─────────────────┐
       │  Verification   │  ← Compare outputs
       │  Dashboard      │
       └─────────────────┘

Key Features

• ✅ Write intent, not implementation - Express what you want, not how to do it
• ✅ Automatic verification - Both paths must produce identical outputs
• ✅ Gradual migration - Start Python-only, migrate to direct runtime as confidence grows
• ✅ Confidence-based routing - Route traffic based on empirical reliability
• ✅ Rich debugging - Debug at semantic level across both runtimes
• ✅ Performance visibility - Know exactly how much faster the optimized path is

Project Status

Current Phase: initializing

• Architecture design
• Vesper specification v0.1
• Python code generator (in progress)
• Direct runtime core (planned)
• Differential testing framework (planned)
• First production deployment (planned)

Documentation

• Architecture Overview - System design and dual-path execution
• Vesper Specification - Complete format reference

Repository Structure

vesper/
├── README.md                 # This file
├── docs/                     # Documentation
│   ├── ARCHITECTURE.md
│   ├── VESPER_SPEC.md
├── spec/                     # Vesper format definitions
│   ├── v0.1/
│   │   ├── schema.json
│   │   └── examples/
├── python/                   # Python implementation
│   ├── vesper_compiler/      # Vesper → Python code generator
│   ├── vesper_runtime/       # Python execution runtime
│   └── tests/
├── rust/                     # Direct runtime (Rust)
│   ├── vesper_core/          # Core semantic interpreter
│   ├── vesper_jit/           # JIT compiler
│   └── tests/
├── tools/                    # CLI and utilities
│   ├── cli/                  # `vesper` command-line tool
│   ├── dashboard/            # Web UI for verification
│   └── profiler/             # Performance analysis
├── examples/                 # Example semantic nodes
│   ├── hello_world/
│   ├── payment_handler/
│   └── data_pipeline/
└── tests/
    ├── differential/         # Differential testing
    ├── integration/
    └── property/             # Property-based tests

Contributing

We welcome contributions! This is a research project exploring the future of software development.

See CONTRIBUTING.md for guidelines.

Areas We Need Help

• 🔨 Python code generator - Converting Vesper to idiomatic Python
• 🦀 Rust runtime - Building the direct execution path
• 🧪 Testing frameworks - Differential and property-based testing
• 📚 Documentation - Examples, tutorials, best practices
• 🎨 Tooling - IDE plugins, debuggers, visualizations

Research Questions

This project explores several open questions:

1. Can LLMs reason more effectively with semantic specifications than traditional code?
2. What's the performance overhead of semantic interpretation vs JIT compilation?
3. At what confidence threshold can we safely migrate from Python to direct runtime?
4. How do we maintain debuggability without human-readable code?
5. Can semantic specifications enable automatic optimization based on runtime behavior?

Inspiration & Related Work

• LLVM IR - Proven intermediate representation for compilers
• WebAssembly - Portable compilation target with security properties
• TLA+ - Formal specification language for distributed systems
• Dafny - Verified programming language
• NormCode - Semi-formal language for AI planning

License

MIT License - see LICENSE for details.

Citation

If you use this work in research, please cite:

@software{vesper_framework,
  title = {Vesper: Verified Execution Framework for LLM-Native Software},
  author = {Witlox},
  year = {2025},
  url = {https://github.com/witlox/vesper}
}

Contact

• GitHub: github.com/witlox/vesper
• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Vesper - Guiding the transition from traditional to LLM-native software development