The dsh-tools half of the Code Mode RFC (its fourth, final change): the registry gains its first config — mode: native | code | both — and OWNS how its tools reach the model. 'code' contributes exactly one wire tool, run_code, plus a lazy tools:sdk prompt section declaring every other tool as a generated TypeScript API (jsonSchemaToTs: total over the defineTool subset, unknown degradation, lexicographic byte-identical rendering); 'both' ships both representations; 'native' is byte-for-byte the old behavior. Non-native modes fail every assembly loudly without a typescript-language ctx.codeRuntime. run_code's dispatch bridge: JSON-normalizes each binding argument before dispatch (what dispatches is what the tool/code-dispatch event logs — the append can never fail on payload shape; BigInt/circulars reject that one call), serializes all program tool calls through a per-run queue (even Promise.all — no concurrency-safety metadata yet), routes every sub-call through tools/pre-execute → tools/post-execute (a deny rejects the program-side promise), drops sub-call additionalContext (no safe outlet mid-run; pinned), owns a run-scoped abort that follows the outer signal in and fires on settlement (in-flight sub-dispatch aborted, queued abandoned, queue drained before returning), and converts a failed run into CodeRunFailedError → a structured isError carrying kind + captured logs. tool/code-dispatch joins SessionEventMap by declaration merging (log-only; deriveMessages ignores it). The composed surface: the tools config forwards through agent-core and both app packages; examples/code-agent + demo:code run the worker runtime under mode code (keyless boot smoke + a with-key e2e proving the collapsed [run_code] header, the dispatch events, and the file the program wrote); two new snapshot scenarios (code-mode-turn, both-mode-turn) record the SDK section, collapsed header, dispatch events, and result card — each its own header-pinning class (the harness gains per-scenario config overlays and per-class pins). Catalogs, graphs, cookbook, hooks-bridge notes, and the RFC (moved to implemented/, restructured to decision-era headings) updated in the same change.
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.