Predicate Commands (modal predicate)

Manage and test predicates — the cryptographic conditions that guard transitions.

List Predicates

modal predicate list [OPTIONS]

List all available predicates.

Options:

Option	Description
--builtin	Show only built-in predicates
--custom	Show only custom predicates
--verbose	Show detailed descriptions

Example output:

BUILTIN PREDICATES:
  signed_by        Verify ed25519 signature
  threshold        n-of-m multisig verification
  oracle_attests   External oracle attestation
  before           Timestamp before constraint
  after            Timestamp after constraint
  hash_matches     SHA256 preimage verification
  num_eq           Numeric equality
  num_lt           Numeric less than
  num_gt           Numeric greater than
  num_lte          Numeric less than or equal
  num_gte          Numeric greater than or equal
  text_eq          Text equality
  text_contains    Text contains substring
  bool_is          Boolean value check

Predicate Info

modal predicate info <NAME>

Get detailed information about a predicate.

Example:

modal predicate info signed_by

Output:

PREDICATE: signed_by

DESCRIPTION:
  Verifies an ed25519 signature against a public key stored at a path.

PARAMETERS:
  path      Path to .id file containing public key
  
IMPLICIT:
  signature  Taken from commit signature
  message    The canonical commit hash being signed

USAGE IN MODALITY:
  +signed_by(/parties/alice.id)

EXAMPLE:
  transition APPROVE: pending -> approved
    +signed_by(/parties/alice.id)

Test Predicate

modal predicate test <NAME> [OPTIONS]

Test a predicate with sample data.

Options:

Option	Description
--data <JSON>	Test data as JSON
--file <FILE>	Load test data from file
--verbose	Show detailed evaluation

Examples:

# Test signed_by predicate
modal predicate test signed_by --data '{
  "path": "/parties/alice.id",
  "public_key": "ed25519:abc123...",
  "signature": "def456...",
  "message": "commit_hash_here"
}'

# Test threshold predicate
modal predicate test threshold --data '{
  "path": "/treasury/signers",
  "n": 2,
  "m": 3,
  "signatures": ["sig1", "sig2"]
}'

# Test from file
modal predicate test oracle_attests --file test-oracle.json

Create Custom Predicate

modal predicate create <NAME> [OPTIONS]

Scaffold a new custom predicate project.

Options:

Option	Description
--path <PATH>	Output directory
--lang <LANG>	Language (rust/assemblyscript)

Example:

modal predicate create kyc_verified --path ./predicates/kyc

Creates:

predicates/kyc/
├── Cargo.toml
├── src/
│   └── lib.rs        # Predicate implementation
├── tests/
│   └── test.rs       # Test cases
└── README.md

Standard Predicates Reference

Signature Predicates

Predicate	Description	Usage
signed_by(path)	Single signature	+signed_by(/alice.id)
threshold(path, n, m)	n-of-m multisig	+threshold(/signers, 2, 3)

Oracle Predicates

Predicate	Description	Usage
oracle_attests(oracle, claim, value)	Oracle attestation	+oracle_attests(/oracle.id, "price", ">100")

Timestamp Predicates

Predicate	Description	Usage
before(path)	Before timestamp	+before(/deadline.datetime)
after(path)	After timestamp	+after(/unlock.datetime)

Value Predicates

Predicate	Description	Usage
num_eq(path, value)	Numeric equals	+num_eq(/amount, 100)
num_gt(path, value)	Numeric greater than	+num_gt(/balance, 0)
num_lt(path, value)	Numeric less than	+num_lt(/count, 10)
num_gte(path, value)	Greater or equal	+num_gte(/price, 50)
num_lte(path, value)	Less or equal	+num_lte(/fee, 5)
text_eq(path, value)	Text equals	+text_eq(/status.text, "active")
text_contains(path, sub)	Contains substring	+text_contains(/name, "Inc")
bool_is(path, value)	Boolean check	+bool_is(/active.bool, true)

Cryptographic Predicates

Predicate	Description	Usage
hash_matches(hash, preimage)	SHA256 verification	+hash_matches(/commit.hash, /reveal.text)