Response Schemas

Operations that return data via file descriptor use specific encoding formats based on operation type.

Sub-VM Result Encoding

Operations that spawn sub-VMs (CallContract Message, RunNondet Message, Sandbox Message) return results through a file descriptor with the following binary format:

[result_code: u8][data: bytes]

Where result_code is a result_code:

• return (0): Successful execution

• user_error (1): Contract-initiated error

• vm_error (2): VM-level error

The data portion depends on the result code:

• return: Calldata Encoded return value

• user_error: Calldata Encoded error value

• vm_error: UTF-8 encoded vm_error string

Validity Of A Proposed Result

A result the executor did not compute itself — the leader-proposed non-deterministic result consumed in Sync Mode and Validator Mode — is accepted only if it satisfies all of the following. A rejected proposal is replaced by a derived VMError. Sync mode returns that replacement without a vote; validator mode records a disagreement without running the comparison stage

1. The buffer is non-empty. An absent or empty proposal yields leader_fault nondet_output absent.

2. result_code is one of return, user_error or vm_error; any other byte yields leader_fault nondet_output malformed.

3. For return and user_error, data is valid Calldata Encoding with no trailing bytes; otherwise leader_fault nondet_output malformed.

4. For vm_error, data is UTF-8, carries no " # " detail, and names a vm_error path, including the canonical spelling of any parameter. Codes outside the trie yield leader_fault nondet_output malformed.

5. A proposed timeout yields leader_fault nondet_output malformed.

An accepted result that passes Nondeterministic Output Caps is preserved byte for byte, so every node hashes the value that was proposed.

Derived-Outcome Namespace

Following VMError codes are derived by the consuming executor rather than proposed:

1. leader_fault nondet_output absent

2. leader_fault nondet_output malformed

3. leader_fault nondet_output uses_this_error

4. leader_fault nondet_output extra

A proposed code that equals, or extends at a space boundary, leader_fault nondet_output is replaced by leader_fault nondet_output uses_this_error whose parameter is the first 6 characters of the GVM32 (Base32) encoding of sha3_256 of the proposed code. A proposal that is its own replacement maps to the parameter fix_point, which cannot collide with a derived parameter because it is 9 characters long and a derived one is always 6.

This check runs before the trie-validity check, so proposing a derived code verbatim can never produce output byte-equal to the proposal. Distinct proposals may share a parameter; the mapping is deterministic and the value carries no meaning beyond identifying the proposal as rejected.

Module Result Encoding

Operations that invoke external modules (WebRender, WebRequest, ExecPrompt, ExecPromptTemplate) return results as Calldata Encoded data with a success/error wrapper:

// On success
{
  "ok": <result>
}

// On error
{
  "error": <error_details>
}

The <result> structure depends on the operation:

WebRender Response

Returns one of the following based on render mode:

// For mode "text"
{"ok": {"text": String}}

// For mode "html" (returns HTTP response)
{"ok": {"response": Response}}

// For mode "screenshot"
{"ok": {"image": Bytes}}

Where Response is:

{
  "status": Number,           // HTTP status code (u16)
  "headers": Map,             // String -> Bytes mapping
  "body": Bytes               // Response body
}

WebRequest Response

{
  "ok": {
    "status": Number,         // HTTP status code (u16)
    "headers": Map,           // String -> Bytes mapping of response headers
    "body": Bytes             // Response body
  }
}

ExecPrompt Response

// When response_format is "text"
{"ok": String}

// When response_format is "json"
{"ok": Object}

ExecPromptTemplate Response

// For EqComparative template (boolean result)
{"ok": Bool}

// For EqNonComparativeValidator template (boolean result)
{"ok": Bool}

// For EqNonComparativeLeader template (text result)
{"ok": String}

Module Error Format

When a module operation fails, the error is returned as:

{
  "error": <GenericValue>
}

Where <GenericValue> may contain error details from the module.