Module errors 

Standard error types for all sisters.

Two error layers:

1. ProtocolError — MCP/JSON-RPC protocol errors (wrong method, bad params, unknown tool). These become JSON-RPC error responses.

2. SisterError — Domain/business logic errors (node not found, invalid state). These become {isError: true} tool results per MCP spec.

MCP Error Handling Rule

If the tool was found and invoked, errors go through isError: true. JSON-RPC errors are only for protocol/routing failures.

Structs

ProtocolError

MCP protocol error — becomes a JSON-RPC error response.

SisterError

Standard error type for ALL sisters — domain/business logic errors.

Enums

ErrorCode

Standard error codes across ALL sisters.

ProtocolErrorCode

Standard JSON-RPC / MCP protocol error codes.

Severity

Severity levels

SuggestedAction

Suggested actions for error recovery

Type Aliases

ProtocolResult

Result type alias for protocol operations

SisterResult

Result type alias for sister operations (domain errors)