Codex review of PR #88 found three issues in the example-app extraction: A1 — examples/coding-agent/README.md's plugin table still listed the OLD direct-wired leaf entries (agent-loop, session-persistence, src/stdio-chat.ts — the whole src/ dir is gone). Rewrite it to the four real leaf entries the current cordis.yml loads (hmr, llm-deepseek, bash, stdio-agent), noting that tool-bash/persistence/agent/loop now live inside the agent-core + stdio-agent bundles. A2 — the three new app/spine packages (agent-core, stdio-agent, acp-agent) export NO `inject`, so a stray `export default apply` would let unwrapExports collapse the module and silently DROP name/Config WITHOUT crashing — the real-load-path smokes would stay green. agent-core is never Loader-unwrapped at all. Add an explicit export-shape guard per package: assert no `default` export and that the real Loader.unwrapExports leaves name/Config/apply intact. Verified each fails when `export default apply` is added. B — soften "structurally unreachable / cannot wire a stdout logger" overclaims in the acp-agent/agent-core READMEs and the implemented RFC: a leaf CAN still add a sibling logger entry; the accurate claim is the app omits one so the default leaf has nothing to get wrong. Keep the safety directive (never add a stdout logger to an ACP leaf).
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 |
|---|---|---|
session/ |
Event-sourced session log + in-memory store | ctx.sessions |
system-prompt/ |
Prompt-section + tool-schema assembly registry | ctx.systemPrompt |
tools/ |
Tool registry + tools/execute waterfall |
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) |
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 only the swappable backends. It lives in core/ because it composes exclusively core/ + interface packages and ships no provider, executor, or UI of its own.