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Your First Contract

This page tracks the canonical first-contract path. Today, the verified path is source-built and uses the language/model CLI against a parser-backed witness model. The local contract-log workflow is verified through the source-built lean modal wrapper and through a temporary Cargo-installed lean wrapper.

1. Run the Verified Source Check​

git clone https://github.com/modality-org/modality.git
cd modality/tests/language
./run-onboarding-tests.sh

The smoke test builds the Rust language CLI from source and validates the first-contract fixture. Passing output includes:

Parts: 1
Transitions: 4
Contract is valid!
All properties are predicates (verifiable).

2. Inspect the Witness Model​

The smoke test validates tests/language/03-first-contract/first-contract.modality:

model FirstContract {
  initial q0

  part flow {
    q0 --> q1: +signed_by(/parties/alice.id)
    q1 --> q2: +signed_by(/parties/bob.id)
    q2 --> q2: +signed_by(/parties/alice.id)
    q2 --> q2: +signed_by(/parties/bob.id)
  }
}

q0, q1, and q2 are opaque witness nodes. The contract meaning lives on the labelled transitions and predicates, here the required signatures for Alice and Bob.

3. Run the Underlying CLI Command​

cd modality/rust
cargo run -q -p modality -- model validate \
  ../tests/language/03-first-contract/first-contract.modality \
  --verbose

This is the source-built language/model CLI, not the installed contract CLI.

Contract CLI Path​

The intended contract-log flow uses modal commands to create a contract, create identities, commit state, and inspect the log. The source-built command modules and lean wrapper now have regression coverage for this local identity-backed flow, including source-built and temporary Cargo-installed debug and release wrappers.

To run the current onboarding smoke bundle:

cd modality
tests/run-onboarding-smokes.sh

That bundle always runs the parser-backed first-contract language check. If a source-built rust/target/debug/modal exists, it also runs the contract-log wrapper smoke; otherwise it prints the exact build command for enabling that second check. To build and run the lean wrapper path in one command:

MODAL_ONBOARDING_BUILD=1 tests/run-onboarding-smokes.sh

To install the same lean wrapper into a temporary Cargo root and verify the installed binary:

MODAL_ONBOARDING_INSTALL=1 tests/run-onboarding-smokes.sh

To run only the source-built wrapper smoke:

cd modality/rust
cargo build -p modal --no-default-features --features contract-onboarding
cd ..
tests/cli/run-first-contract-cli-smoke.sh

The target shape is:

mkdir my-contract && cd my-contract
modal contract create
modal id create --path alice.mod_passfile
modal id create --path bob.mod_passfile
modal c checkout
modal c set-named-id /parties/alice.id alice.mod_passfile
modal c set-named-id /parties/bob.id bob.mod_passfile
modal c commit --all --sign alice.mod_passfile -m "Initial contract setup"
modal c status
modal c log

The smoke checks both JSON and text log output for Alice's signer ID and the commit message, so the plain modal c log command above must show the visible authority evidence and human-readable commit context a new user needs to confirm the signed commit.

What's Next?​