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Introduction

Use this tutorial when you are new to the Credible Layer and want one guided, happy-path run from local project setup to an enforced assertion. By the end of this tutorial, you will:
  1. Set up your project structure
  2. Test your assertion
  3. Deploy your contract
  4. Authenticate with pcl
  5. Create a project
  6. Store your assertion
  7. Submit your assertion to the Credible Layer
  8. Deploy your assertion
  9. Verify that the assertion is working
If you already know the overall flow and only need one task, use the dedicated guides for installation, storing and submitting assertions, or deployment in the platform.

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Prerequisites

Before you begin, make sure you have:

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1. Project Setup

We’ve created an example project that contains complete assertion examples that work out of the box and can serve as a starting point for your own projects. The project can be found here. For a detailed understanding of what an assertion is and how it works, see the Assertion Guide. For testing assertions, see the Testing Assertions guide.
The credible-layer-starter repo has several examples that you can deploy and try out once you’re done with this guide. Specific instructions can be found in the README.
You can clone the example project by running the following command: 
git clone --recurse-submodules https://github.com/phylaxsystems/credible-layer-starter.git
cd credible-layer-starter
Once cloned you have a repository with all required dependencies.

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2. Running Tests

Use the pcl CLI to run your tests: 
pcl test
This command will compile your assertion and run the tests. You should see output looking like this indicating that the tests have passed: 
Ran 2 tests for assertions/test/OwnableAssertion.t.sol:TestOwnableAssertion
[PASS] test_assertionOwnershipChanged() (gas: 806650)
[PASS] test_assertionOwnershipNotChanged() (gas: 804708)
Suite result: ok. 2 passed; 0 failed; 0 skipped; finished in 648.17ms (1.11s CPU time)

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3. Deploy Your Contract

First, import your private key into an encrypted Foundry keystore so you never have to expose it as an environment variable: 
cast wallet import <account_name> --interactive
You’ll be prompted to paste your private key and set a password. Foundry stores the encrypted key locally and will prompt for the password when you sign transactions. Now deploy the Ownable contract: 
forge script script/DeployOwnable.s.sol --rpc-url <RPC_URL> --account <account_name> --broadcast
Explanation of the arguments:
  • <RPC_URL>: The RPC URL of the network you’re deploying to
  • <account_name>: The name you chose when importing your key above
Make sure to note down the address of the deployed contract as you’ll need it to create a project in the next step. It will be the Deployed to: address in the output of the command.

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4. Authenticating with Credible Layer

Here’s a full video that you can use to follow the full process from authentication to activating the assertion:
Before submitting your assertion, you need to authenticate: 
pcl auth login
Make sure to use the same address as you set as the initial owner of the contract in the previous step.
This will provide you with with a URL and an authentication code that you can use to authenticate with the Credible Layer.
If authentication fails, first confirm that your wallet is on the correct network and that pcl is using the expected auth URL. Then use the Troubleshooting guide for the common failure modes.

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5. Create a Project

Once you have deployed your contract, you’ll need to create a project in the platform if you don’t have one already. Navigate to app.phylax.systems and create a new project. When asked to link your contract, use the address of the contract you deployed in the previous step. For a more detailed overview of how to use the platform and manage projects, see the Deploy Assertions guide.

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6. Storing Your Assertion

Next, store your assertion in the Assertion Data Availability layer (Assertion DA): 
pcl store OwnableAssertion
Here OwnableAssertion is the name of the assertion. This command submits your assertion’s bytecode and source code to be stored by the Assertion DA, making it available for verification by the network.

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7. Submitting Your Assertion

Finally, submit your assertion to the platform: 
pcl submit
This will prompt you to select the project and assertion(s) you want to submit. Follow the interactive prompts to complete the submission. Alternatively, you can specify the project and assertion directly as per the output of the pcl store command: 
pcl submit -a 'OwnableAssertion' -p <project_name>
Note that <project_name> is the name of the project you created in the platform, capitalized in the same way as you did when creating the project.

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8. Deploying Your Assertion

To finish the tutorial, open the platform at app.phylax.systems and navigate to the project that the assertion was added to. You’ll notice that there’s one assertion ready for deployment. Go ahead and proceed to review and deploy it. During the review process, you’ll choose whether to deploy to Staging (for testing) or Production (for active protection).
After deployment, your assertion enters a timelock period. During this period, it is marked for enforcement (production) or marked for staging (staging environment). After the timelock expires, the assertion becomes enforced (production) or staged (staging), actively protecting your contract. See the Glossary for details about timelocks.
For a more detailed overview of how to use the platform, see the Deploy Assertions guide.

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9. Verify That The Assertion Is Working

Now that your assertion is deployed and enforced (after the timelock period), let’s verify that it’s working as expected. We’ll do this by attempting to change the ownership of the contract, which should trigger our assertion and prevent the change. First, let’s check the current owner of the Ownable contract. Replace ADDRESS_OF_OWNABLE_CONTRACT with the address of your deployed Ownable contract and RPC_URL with your network’s RPC URL: 
cast call <ADDRESS_OF_OWNABLE_CONTRACT> "owner()" --rpc-url <RPC_URL>
This command should return the initial owner address that was set when we deployed the contract. Next, let’s attempt to transfer ownership to a new address. Make sure you replace NEW_OWNER_ADDRESS with an address that is not the initial owner. This transaction should cause the assertion to revert, which will result in the transaction being dropped: 
cast send <ADDRESS_OF_OWNABLE_CONTRACT> "transferOwnership(address)" <NEW_OWNER_ADDRESS> --rpc-url <RPC_URL> --account <account_name>
The transaction should timeout, which means that the assertion reverted and the transaction was dropped: 
Error: transaction was not confirmed within the timeout
To confirm that the ownership hasn’t changed, let’s check the owner again: 
cast call <ADDRESS_OF_OWNABLE_CONTRACT> "owner()" --rpc-url <RPC_URL>
The owner should still be the original address, confirming that our assertion successfully prevented the ownership change.

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Conclusion

Congratulations! You’ve successfully created, tested, deployed, and verified your first assertion using pcl. You can now go ahead and start implementing assertions in your own projects.

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Next Steps

  1. Read the Assertions Book: Check out the Assertions Book for more detailed explanations and a collection of assertions for various use cases
  2. Try more complex assertions: We’ve created some more assertions in the credible-layer-starter repo that are ready to be deployed and used with a couple of commands
  3. Integrate with your own projects: Apply assertions to your existing smart contracts
  4. Join the community: Share your assertions and learn from others in the Phylax Telegram
For more detailed information about pcl and its commands, see Store and Submit Assertions and pcl Reference. For a comprehensive list of terms and concepts used in the Credible Layer, see the Glossary.