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 # Halite
 
-The successor to [Salt](https://github.com/Viasat/salt).
+A tool for specification and verification of systems.
 
-[Halite Documentation](doc/halite_outline.md)
+Halite consists of
 
-Please note this is a pre-release version and the API is unstable.
+1. A specification language for defining schemas and constraints
+2. An evaluator that can be used to verify instances or compositions of schemas and constraints.
+3. A generator that can create possible solutions.
+
+Halite is the mineral form of salt (sodium chloride) commonly known as "rock salt".
+This tool is named Halite as the successor to [Salt](https://github.com/Viasat/salt)
+(S-expressions for Actions with Logic Temporal).
+Salt provided a Clojure interface to TLA+.
+Halite provides Edn and Json interfaces for specifying schemas
+and constraints. Constraints are solved by [Choco-solver](https://choco-solver.org/).
+
+## Rationale
+
+Systems are composed of services.
+Service components are often maintained by different teams.
+The interfaces and behaviors of the system need to be clear, precise, and verifiable in order to create a cohesive system.
+Halite provides a formal way to define interfaces and behaviors.
+Using this approach to model and reason about a system enables proof that the design is logical, and that the outcomes are known.
+
+We see potential use cases to include
+
+1. **Proving systems.** As a standalone proof system to ensure that the designed composition of services is logical, and that specific instances of communication are valid.
+2. **Constructing systems.** As an integrated shell for the system that automatically validates boundary communication.
+3. **Applying constraints in programs.** Integrated into services to validate inputs and outputs of processes.
+
+## Usage
+
+This is a pre-release version and the API is unstable.
+No releases are available yet, instead clone this repo or use as a git dependency.
+
+## Documentation
+
+Coming soon: [Outline](doc/halite_outline.md)
+
+Meanwhile:
+
+* [Fields](doc/halite/explanation/halite_abstract-field.md)
+* [Specifications](doc/halite/explanation/halite_abstract-spec.md)
+
+
+## Contributing
+
+Pull requests and issues are welcome.
+
+### Setup
+
+Install Leinigen and Java.
+
+### Testing
+
+```
+lein test
+```