7ef21239ca
Providers stream token-sized deltas, so a session log stores hundreds of near-identical assistant/chunk lines whose JSON envelopes dwarf their payloads (~56x measured on a real DeepSeek session, 73% of file bytes). Add a lossless storage codec to dsh-session: packChunkRuns() folds each run of >=3 consecutive same-block delta chunks into one storage row -- text-chunks / reasoning-chunks / tool-call-chunks, bare slash-less tags like the header line's 'session' so rows cannot be confused with session events -- and decodeStorageRecord() expands rows back to the exact original events (seq0/time0 + dt gap array reconstruct every member's seq/time; tool-call rows carry the run-constant id/name). The encoder whitelists exact shapes and stores anything unrecognized verbatim; the decoder validates row-tagged values and fails loud on malformation. The JSONL backend gains a packChunks config (default false). Writing packs only when enabled -- default-off output stays byte-identical to the previous layout, so snapshot goldens are untouched. Reading is layout-blind: scanLog always decodes rows and now checks seq contiguity with a cursor instead of the line index, so packed, unpacked, and mixed files all load identically. Fixture readers (llm-replay parseSessionLog, acp-snapshot normalizeSessionLog) share the codec; the normalizer zeroes a row's time0/dt exactly like an event's time. The two demo bundles plumb packChunks from cordis.yml to the backend. Measured on a real coding session: 105 KB -> 42 KB (-60%), 475 lines -> 74, with reasoning/tool-call heavy sessions saving the most. Covered by example + fast-check round-trip codec tests, backend packed/mixed/torn- tail specs, and an end-to-end demo run loading a packed log through a default-config backend.
core/ — product API spine
The session log, system-prompt assembly, tool registry, agent vocabulary, and concrete loop that form the harness's default control spine. 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/ |
Scoped tool registry + pre-policy, guards, around-dispatch, post-policy, and final-result observation | ctx.tools |
agent/ |
Agent interface, registry, agent/* event vocabulary |
ctx.agents |
agent-loop/ |
The concrete loop plugin: ReactLoopAgent + the loop driver |
ctx.agentLoop |
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.
The default composition that wires this spine into a runnable agent lives in examples/agent-spine-demo: one bundle plugin that loads the control spine plus selected default capabilities (timer + llm + sessions + system-prompt + tools + agents + invariants + the local skill family + tool-bash + agent-loop) and forwards agent-loop's agents list as its own config. It sits in examples/ — ready-to-run demo/reference bundles — not in core/: core/ ships the swappable spine pieces, while a demo bundle picks one concrete composition of them and adds a front door.