Crate Layout

Crates

Crate	Responsibility
`orbit-cli`	Clap-based CLI entrypoint.
`orbit-core`	Runtime bootstrap, command dispatch, config layering, default asset seeding. Surfaces `OrbitRuntime` to `orbit-cli`. Does not depend on `orbit-agent`.
`orbit-engine`	Activity and job execution, template rendering, retry logic. Owns the `backend: cli` subprocess runner, which references `orbit-agent::{Agent, AgentConfig}` directly.
`orbit-agent`	Per-provider `AgentRuntime` implementations under `providers/<name>/<name>_runtime.rs` (claude, codex, gemini, openai_compat, anthropic, ollama, mock_agent). Hosts HTTP `LoopTransport` primitives.
`orbit-tools`	Tool registry plus built-in graph, fs, and policy-aware exec tools.
`orbit-knowledge`	Knowledge/graph parsing and storage helpers. Multi-language source parsing (Rust, Go, Java, JavaScript, Python).
`orbit-policy`	Filesystem-scoping policy engine. Owns `FsProfile` resolution and `denyRead` / `denyModify` evaluation.
`orbit-exec`	Process / sandbox / supervision primitives for shell-command execution under an `FsProfile`.
`orbit-store`	Layered store pattern (YAML + SQLite).
`orbit-mcp`	Model Context Protocol adapter using `rmcp`. Consumed by `orbit-cli` via `orbit mcp serve`.
`orbit-common`	Leaf — shared domain types (`OrbitError`, IDs, activity/job schemas) and generic utilities (fs, redaction, logging, blob storage).

Dependency Direction

orbit-common → orbit-policy, orbit-exec, orbit-knowledge → orbit-tools → orbit-agent → orbit-engine → orbit-core → orbit-cli
            ↘ orbit-store ──────────────────────────────────────────────────↗            ↗
            ↘ orbit-mcp ─────────────────────────────────────────────────────────────────────────────────────────↗

Do not add cross-crate dependencies that violate this direction. Lower layers stay reusable and free of higher-level runtime concerns. In particular, orbit-core must not depend on orbit-agent; the backend: cli subprocess runner in orbit-engine is the bridge.