013f12963b
Codex follow-up findings on the carrier commit, both verified: B: the invariant guard only protected the bind path — an overlay key colliding with a non-configurable, non-writable OWN prop of a (pathological) base would have the get trap report the overlay value, which the engine rejects as a proxy invariant violation (TypeError at read time). The pin check now runs FIRST and covers both invariant-pinned shapes (non-writable own data prop reported as-is; getterless non-configurable accessor reported undefined via the delegated read) before overlay and bind alike. Such a base forgoes scope filtering by construction — correctness of the read beats filtering for a base no production code ships. C: `constructor` is looked up for identity, never invoked as a subject method — binding it broke `carrier.constructor === Subject` for no benefit; it now returns raw (the same special-case withProps had). Both pinned in scope.spec: the frozen-own-filter collision yields the base's value without throwing, and class identity survives the carrier.
core/ — product API spine
The packages every harness build is assembled from: the session log, the system-prompt assembly, the tool registry, the agent vocabulary, and the one concrete loop that drives them. 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/ |
Tool registry + tools/pre-execute/tools/post-execute pipeline |
ctx.tools |
agent/ |
Agent interface, registry, agent/* event vocabulary |
ctx.agents |
agent-loop/ |
The concrete loop plugin: ReactLoopAgent + the loop driver |
ctx.agentLoop |
agent-core/ |
Bundle plugin: the providerless/executor-less/UI-less spine as code | (loads the spine) |
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; everything else in core/ is interface/vocabulary. Plugins depend on the agent vocabulary, never on agent-loop directly, so the loop stays swappable.
agent-core is the composition counterpart: one bundle plugin that loads the whole providerless spine (timer + llm + sessions + system-prompt + tools + agents + invariants + tool-bash + agent-loop) and forwards agent-loop's agents list as its own config. App packages (ui/stdio-agent, ui/acp-agent) consume it and add only a front door; a leaf adds the swappable backends plus any optional product tools it wants to expose. It lives in core/ because it composes exclusively core/ + interface packages and ships no provider, executor, or UI of its own.