Reference

Use the reference when you need an exact command, manifest field, target contract, or protocol behavior. Start with a guide when you are learning a workflow for the first time.

• The once.toml Manifest covers workspace discovery, root-only configuration, target declarations, and path resolution.
• The Command-line Reference covers every subcommand the once binary exposes, with its synopsis, options, and arguments.
• The Modules Reference documents how projects define target kinds and actions.
• The Target-kind Reference enumerates every built-in target kind, including its attributes, dependency edges, capabilities, and outputs.
• The Memory Reference documents project-local runtime state, the evidence database, and location rules.
• The Model Context Protocol Reference documents the Model Context Protocol surface that once mcp serves: transport, handshake, error model, an example session, and the complete tool catalog.
• The Live Run Event Protocol Reference documents the gRPC surface Once uses to stream typed events to a compatible ingest server: what the client sends, delivery guarantees, the event catalog, redaction rules, and how to enable ingest.