Commit Methods

Modality contracts are append-only logs of commits. Each commit contains one or more actions, and each action has a method that determines what it does.

POST

The most common method — writes data to a path in this contract's state.

{
  "method": "post",
  "path": "/users/alice.id",
  "value": "12D3KooWAbCdEfGhIjKlMnOpQrStUvWxYz..."
}

After the commit is accepted, formulas on this contract can name that path (signed_by(/users/alice.id), text_eq, state_exists, …).

Path Types

Paths must end with a known extension:

Extension	Type	Example Value
.bool	Boolean	true or false
.text	Text string	"Hello world"
.date	Date	"2024-01-15"
.datetime	Date and time	"2024-01-15T10:30:00Z"
.json	JSON object	{"key": "value"}
.md	Markdown	"# Title\n\nContent..."
.id	Modality ID	"12D3KooW..."
.wasm	WebAssembly	Base64-encoded WASM
.modality	Rules/formulas	Modality syntax

MODEL

Sets or replaces the contract's state machine model. Unlike rules, models can be replaced.

{
  "method": "model",
  "value": "model escrow { initial idle; idle -> funded [DEPOSIT]; funded -> released [RELEASE] }"
}

CLI Usage

modal contract commit --method model \
  --value 'model members_only { initial active; active -> active [] }' \
  --sign alice

Note: Models define structure but don't enforce security on their own. Use RULE methods to add protection that persists even if the model is replaced.

RULE

Adds a temporal logic constraint to the contract. Rules are accumulated over time and all must be satisfied.

{
  "method": "rule",
  "path": "/rules/auth.modality",
  "value": "always([<+signed_by(/users/alice.id)>] true)"
}

Rules must have paths ending in .modality.

REPOST

Copies a snapshot of another contract's value into this contract so later rules can name it like any other path. It is not a live pointer: later updates on the source do not change this contract until you REPOST again.

{
  "method": "repost",
  "path": "/reposts/abc123def456/announcements/latest.text",
  "value": "Hello from the other contract!",
  "source_contract": "abc123def456",
  "source_path": "/announcements/latest.text",
  "source_commit": "a1b2c3..."
}

• path — dest path in this contract (a normal /... path). Default dest is /reposts/<source_id><source_path>. Choose a path like /parties/alice.id when the imported value should be that identity.
• value — bytes copied from the source.
• source_contract, source_path, source_commit — provenance. The hub checks that the source contract at source_commit has value at source_path.

After accept, dest is ordinary accepted state. Example: REPOST Alice's key to /parties/alice.id, then signed_by(/parties/alice.id) works. Method label is +REPOST (not +POST). modifies(dest) matches. post_to_path stays POST-only. Models that only allow +POST must also allow +REPOST (or an unlabeled write loop) before import commits will pass.

Working tree

Default dest files live under reposts/<source_id>/.... Custom dests live under state/ like POST. modal commit --all emits method: "repost" for paths staged by modal repost.

CLI Usage

# Default dest /reposts/<source_id>/announcements/latest.text
modal repost abc123def456 /announcements/latest.text

# Custom dest so formulas can say signed_by(/parties/alice.id)
modal repost abc123def456 /parties/alice.id /parties/alice.id

# Source is a local contract directory (no hub)
modal repost abc123def456 /notes/hello.text --from-dir ../source-contract

modal commit --all

CREATE

Creates a new asset in the contract.

{
  "method": "create",
  "value": {
    "asset_id": "token1",
    "quantity": 21000000,
    "divisibility": 100000000
  }
}

SEND

Sends assets to another contract.

{
  "method": "send",
  "value": {
    "asset_id": "token1",
    "to_contract": "target_contract_id",
    "amount": 1000
  }
}

RECV

Receives assets from a SEND in another contract. The SEND commit must already be sequenced. When the network requires validator certs, dest apply also needs a prefix-cert supermajority through that SEND commit.

{
  "method": "recv",
  "value": {
    "send_commit_id": "abc123..."
  }
}

INVOKE

Executes a WASM program stored in the contract.

{
  "method": "invoke",
  "path": "/__programs__/calculator.wasm",
  "value": {
    "args": {
      "operation": "add",
      "a": 5,
      "b": 3
    }
  }
}