agent-loop: behavior tests for retry-while-busy, cancelled recovery windows, no-facts stream failures, idle-listener preemption, rejected driver promises under whenIdle, finish-chunk failures after step close, presentationMeta persistence, pre-aborted and torn-down create/resume signals, and configured-start failures over existing artifacts or after teardown. The remaining guards that no public path can reach carry justified v8 ignore annotations naming the invariant that starves them. acp bridge: cover the retry-adoption path (a retry turn resolves the prompt the failed turn deferred), the no-retry quiescence rejection, and the admission-blocked cancelled settlement; the synchronous send-throw catch is annotated as a future-proofing guard since the machine's send() contains listener failures.
core/ — product API spine
The session log, system-prompt assembly, tool registry, agent vocabulary, and concrete loop that form the harness's default control spine. These are product packages — the stable surface plugins and consumers build against.
| Package | Role | ctx key |
|---|---|---|
scope/ |
Scoped-context registration primitive (scope tags, scope-filtered dispatch) | (library — no ctx key) |
session/ |
Event-sourced session log + in-memory store | ctx.sessions |
system-prompt/ |
Prompt-section + tool-schema assembly registry | ctx.systemPrompt |
tools/ |
Scoped tool registry + pre-policy, guards, around-dispatch, post-policy, and final-result observation | ctx.tools |
agent/ |
Agent interface, live registry, process-local initiator scope, agent/* event vocabulary |
ctx.agents |
agent-loop/ |
Concrete plugin implementing the public Agent contract and owning the loop driver |
ctx.agentLoop |
scope/ is the one non-service package here: a dependency-free library (createScope/scopeOf/scopeTarget) the registries and the loop build per-agent scoping on — it sits below session/ and system-prompt/ in the module graph precisely so they can consume it without a cycle.
agent-loop is the one concrete implementation of the agent seam and lives here because it is the harness's default product loop. It runs each driver inside ctx.agents.withInitiator(). Extension plugins depend on agent, including when they need the initiating Agent, and never on agent-loop directly, so the loop stays swappable.
The default composition that wires this spine into a runnable agent lives in examples/agent-spine-demo: one bundle plugin that loads the control spine plus selected default capabilities (timer + llm + sessions + fallback session titles + system-prompt + tools + agents + invariants + the local skill family + tool-bash + workspace-context + agent-loop) and forwards agent-loop's agents list as its own config. It sits in examples/ — ready-to-run demo/reference bundles — not in core/: core/ ships the swappable spine pieces, while a demo bundle picks one concrete composition of them and adds a front door.