adbba0deb2
Review follow-up (#196): a listed name with no registered tool was silently ignored; misconfiguration must block work instead. The check lives in the assembly — the earliest moment the registered tool set exists (tool plugins register after the service constructs) and the only universal one (cordis has no "all plugins loaded" event; registrations change at any time). assemble() is now async so the throw surfaces as a rejection rather than a synchronous escape from a Promise-returning method. Blast radius, pinned by a loop-level test: the rejection reaches the turn's outer catch — the turn closes balanced with an `error` reason, agent/error mirrors it, no step opens, no request/header is logged, no request reaches the adapter, and the agent returns to idle; every turn fails identically until the config is fixed. A boot-time validation pass was considered and rejected (recorded in the RFC). The general principle — misconfiguration fails loud, never a silent skip — is added to AGENTS.md.
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/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) |
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.