Architecture

Unio is a Rust workspace organized around a local daemon. The CLI is thin: it collects user input and sends work to the daemon. The daemon owns state, session and run lifecycle, approvals, tool execution, storage, and trace events.

Workspace Layout

apps/
  cli/       user-facing unio command
  daemon/    local runtime for sessions, runs, tools, storage, and trace

crates/
  core/           IDs, paths, metadata, shared utilities
  protocol/       CLI, daemon, and agent protocol types
  agent/          root agent, planner, sub-agent, and skill-agent contracts
  model/          model provider abstraction and mock provider
  tools/          tool registry and execution contract
  security/       approval policy and risk precheck
  skills/         skill discovery and skill-tool execution
  storage/        SQLite metadata and JSONL transcript stores
  observability/  trace and context events

Runtime Flow

user
  -> unio CLI
  -> daemon
  -> agent
  -> model provider or tool
  -> security approval when needed
  -> storage and trace records
  -> user-visible result

Current Contracts

• apps/cli owns user interaction and command parsing.
• apps/daemon owns runtime orchestration and persistence.
• crates/protocol defines shared request and response types.
• crates/security returns allow, deny, or approval-required decisions.
• crates/tools executes registered tools only after precheck.
• crates/storage persists metadata, transcripts, and trace data.
• crates/observability records structured runtime events.

Design Principles

• Keep model calls, tool execution, and persistence out of the CLI.
• Route every risky operation through the security policy.
• Resolve model configuration in the model crate from ~/.unio/config.toml, with environment variables as higher-precedence overrides.
• Make local development possible with the mock provider.
• Prefer explicit IDs for sessions, runs, agents, and traces.