84088300bc
Three findings from the PR-4 convergence round: (A) A root-undefined binding argument passed normalization untouched, so the sub-call DISPATCHED and only then failed the tool/code-dispatch append (Session.append rejects undefined event data) — a sub-call executed with no log record, violating the nothing-executes-unlogged contract. And the tool received the SAME object later handed to the append, so a tool mutating its args desynced the logged record from what was dispatched (or re-poisoned the append). jsonNormalizeArgs now rejects undefined up front with a model-correctable message and returns TWO independent parses of the canonical JSON text: the tool gets one, the event logs the sibling — identical by construction, mutation-proof. (B) The bridge built its bindings record with plain-object assignment, so a registered tool named __proto__ hit the prototype setter and silently vanished (the runtime host resolves binding names as own properties). The record is now null-prototype with defineProperty, mirroring the worker-side namespace build. (B) The header-pin sanity assertions ran only inside NON-pinning scenarios, so a class consisting solely of its pinning scenario (the two Code Mode classes) would accept a re-recorded pin carrying several headers or a header-delta. A fixtures meta-test now asserts every pinning fixture directly.
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.