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A Solidity runtime verification tool for property based testing.


Scribble is useful to prepare smart contracts for behavior verification with Diligence Fuzzing or with tools, such as Mythril.

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Principles and Design Goals

The design of the Scribble specification language takes inspiration from several existing languages and we expect the language to evolve gradually as we gain more experience in using it. We rely on the following principles and design goals to guide language evolution:

  1. Specifications are easy to understand by developers and auditors
  2. Specifications are simple to reason about
  3. Specifications can be efficiently checked using off-the-shelf analysis tools
  4. A small number of core specification constructs are sufficient to express and reason about more advanced constructs

We are aware that this will make it difficult or impossible to express certain properties. We encourage users to reach out if they encounter such properties. However, it is not our itention to support every property imaginable. We consider it a great success if Scribble is able to capture 95% of the properties that users want to express.


Install Scribble with npm:

npm install -g eth-scribble

Use CLI tool with the Solidity source file:

scribble sample.sol

Use --help to see all available features.

Extension for VS Code

There is a Scribble extension for VSCode that enhances user experience: prividing syntax highlight, hints-on-hover and other features.

Note that it is maintained in separate repostory. Report extension-related suggestions and issues there.


For more information on the Scribble specification language, and any other documentation, go to: Scribble Documentation

Development installation


Preinstall NodeJS of compatible version. If there is a need to run different NodeJS versions, consider using NVM or similar tool for your platform.

Clone and build

Clone repository, install and link:

git clone
cd scribble/
npm install
npm link

Prior to running the tests it would be better to setup local compiler cache:

scribble --download-compilers native wasm