Add a SQLite SessionPersistence backend (node:sqlite), a SECOND
implementation built to prove the abstract seam + the shared
runPersistenceContract suite are genuinely backend-agnostic. Each
SessionEvent maps 1:1 onto an events row (session_id, seq, type, time,
data); append is an INSERT inside a transaction asserting the
contiguous-seq contract; the mutable SessionSummary lives in the
sessions metadata row.
It satisfies the SAME contract semantics as the JSONL backend, expressed
over rows instead of file bytes:
- Lazy materialization: create() records intent in memory; no row until
the first append (a never-appended session is absent from has()/list()
via a materialized flag set inside the first append transaction).
- Crash-tail-on-load: load() returns events only through the last
complete turn/end and deletes the uncommitted tail; a seq gap in the
committed region makes the session unloadable.
- Transactional append: a mid-batch failure (a UNIQUE seq collision from
a concurrent writer) rolls back entirely, keeping the cursor truthful.
Like the JSONL backend it is also the write-path plugin (session/event →
buffer → session/flush drain, onCreated seed/adopt/collision handling,
HMR seeding, dispose-to-quiescence). The package runs the shared
runPersistenceContract suite plus SQLite-specific tests (transaction
rollback, crash-tail cut, schema version, HMR adoption).
Docs flip every "SQLite is future/deferred" reference (ADR 0016,
architecture.md, the persistence module doc + README) to "implemented;
the contract holds both backends to identical semantics".
Add the agent-creation factory seam on ctx.agents (AgentRegistry):
setFactory/create/resume plus the AgentFactory interface and
CreateAgentOptions/ResumeAgentOptions. AgentLoop implements AgentFactory
and registers itself via ctx.agents.setFactory(this), so plugins
create/resume agents through the interface without depending on the
concrete loop package.
- create({ agentId, sessionId, meta?, agentOptions? }) — programmatic
create on a caller-supplied session id (e.g. an ACP-generated id).
- resume({ agentId, resumeSessionId, agentOptions? }) — load a persisted
session via ctx.sessionPersistence (RFC 009) and resume an agent on it;
the live session id is the resumed id, turn numbering and derived
history continue from the loaded log. sessionPersistence is NOT
hard-injected (non-persistent demos still work); resume rejects with a
typed error when it is absent. assertAgentIdFree runs before any
session is created (and again after the load await) so a duplicate id
never leaves an orphaned live session.
Adds the runtime dsh-session-persistence dependency to agent-loop.
Add the durable session-persistence capability seam (ADR 0016): an
abstract SessionPersistence service (dsh-session-persistence,
ctx.sessionPersistence) defining create/append/load/list/has/delete/
update over the existing SessionEvent — no parallel persisted type — and
a first implementation (dsh-session-persistence-jsonl): an append-only
JSONL log per session with crash-safe atomic writes, truncation-repair
of a never-committed crash tail, and a read/replay path. SessionMeta
(format version, cwd, lineage) travels out-of-log via session.header.
A shared runPersistenceContract suite holds every backend to the same
append-only / contiguous-seq / lazy-materialization / serializability
semantics.
Config-driven create() now uses a per-run ${id}-session-<uuid> session
id so a fixed name no longer collides with an on-disk log once a durable
backend is loaded; each run is a new session (a demo simplification). The
examples drop their hand-rolled session-jsonl.ts and load the JSONL
backend via cordis.yml; CI smoke-loads it too.
The agent-facing create/resume factory that consumes load() is a
separate seam, deferred to a follow-up; this change stops at the load
primitive and does not reach into the loop.
After turn/start was appended, nothing guaranteed a matching turn/end: a throw
from a boundary emit (agent/turn-start, agent/step-start, the normal-path
agent/turn-end) escaped runTurn, and the outer runLoop backstop logged an
error but never appended turn/end — leaving an unbalanced turn that replay,
telemetry, and the invariants plugin all assume is impossible.
runTurn is restructured around idempotent finalizers that satisfy the four
traps a naive finally would hit:
- closeStep()/closeTurn(emit) are guarded (stepOpen/turnEnded) so they run at
most once; the agent/step-end and agent/error emits are contained so a
throwing listener can't strand the turn open.
- failTurn() records the single error event + reason and emits agent/error
exactly once (errorReported guard) — no double-logging when the outer catch
also runs (e.g. a step error followed by a throwing turn-end listener).
- the catch closes an open step BEFORE turn/end (invariants reject turn/end
while a step is open), and rethrows ONLY pre-turn throws (turnStarted false),
where no turn/end is owed, so the backstop still nets them.
- disposal precedence: reason stays disposed only when disposed AND no error
was reported; otherwise the error reason wins.
Tests (with the invariants plugin loaded as a balance oracle): throwing
turn-start (one error, one turn/end, no step), throwing step-start (step/end
before turn/end), throwing agent/error on a step-error path (balanced, loop
survives), disposal mid-turn (reason disposed, no error event), a pre-turn
turn/start-append throw (rethrown to the backstop, no turn/end owed), and a
step error + throwing turn-end listener (error logged exactly once). Verified
all six fail against a simulated finalizer bypass. dsh-invariants added as an
agent-loop devDependency (test-only oracle; no package cycle).
Introduce HarnessError in dsh-llm (the leaf package): a stable machine-routable
code distinct from the message, cause chaining, name from the subclass, plus
isHarnessError. LlmError, ToolArgsError, and InvariantError now extend it.
Tool failures carry the structure end-to-end: ToolExecutionResult gains
error: { name, code } (populated from a thrown HarnessError), and the loop
forwards it onto the tool/result session event (which gained the same optional
field) for retry/sandbox plugins and replay. The loop's toError wraps non-Error
throws in a HarnessError(code: UNKNOWN, cause) instead of a bare Error.
Landed last and in isolation so it's a pure upgrade over the plain Error+code
the earlier PRs used — independently revertible. Graduates RFC 005 pt 2 ->
ADR 0015; RFC 005 now fully implemented.
Adds fast-check + one tests/properties.spec.ts per protocol-shaped package
(llm/BlockAssembler, session, tools/schema DSL, agent-loop scheduling). The
tools suite includes the RFC 001<->005 composition property (generated args
satisfying a spec pass validateArgs), closing the validator/InferArgs drift
risk from ADR 0011. Loop properties are deterministic (settle on agent/status,
no sleeps).
The BlockAssembler suite found a real bug on first run: a duplicate block-end
at the same index overwrote an already-flushed block, so the streamed prefix
disagreed with final blocks(). Fixed (first close wins, matching the existing
straggler rule) + regression test. Graduates RFC 001 -> ADR 0013.
New @deepseek-ai/dsh-invariants plugin (pure listeners, off in prod) asserts
the event taxonomy at runtime — seq monotonicity, turn/step nesting, a
tool/result needs a prior tool/call (NOT the converse), legal agent/status
transitions — and deep-freezes logged event data so mutating history throws.
Seeded sessions are checked + frozen on session/created.
The real RFC 008 fix is always-on: deriveMessages now structured-clones the
content it emits, so the loop's sanctioned request/adapter mutation can no
longer reach back and rewrite the append-only log. The pervasive
DeepReadonly<T> type flip is rejected (compile-only, high-noise, castable) —
recorded in ADR 0012, which folds in RFC 008. Wired into both demos.
The first real LlmAdapter implementations, shipped as a deliberate pair:
same models and wire protocol, completely different internals, so the
StreamChunk protocol is verified across independent implementations.
- dsh-llm-deepseek: hand-rolled fetch + SSE parser + chunk-translation
state machine against the official chat-completions format (thinking
mode via top-level thinking/reasoning_effort; the empty-string
reasoning_content first chunk; usage attached to the finish chunk or
trailing; reasoning_content passback on tool-call turns; disjoint
cache-token accounting).
- dsh-llm-pi-ai: the same endpoint through @earendil-works/pi-ai,
mapping its event vocabulary (parsed tool arguments, in-stream error
events, folded reasoning tokens) onto the same chunks.
The agent loop now honors the in-band error path: an adapter that ends
its stream with finish {kind:error|aborted} (the only option for
adapters that can't throw mid-stream, like pi-ai) is translated into a
step error, so the turn ends error/aborted with a logged error event
instead of a normal completed assistant message. This makes the
StreamChunk error contract real for both adapters; docs/architecture.md
and the StreamChunk doc are updated accordingly.
New yarn test:e2e (vitest.e2e.config.ts, *.e2e.ts) runs key-gated
real-API matrices for both adapters across V4 Flash/Pro and all
thinking/effort levels; it self-skips without DEEPSEEK_API_KEY. Unit
suites run against local node:http mock SSE servers at 100% per-file
coverage.
Three packages following the new capability-seam pattern (interface /
implementation / consumer, now documented in docs/architecture.md):
- dsh-bash: abstract BashExecutor service (ctx.bash) + vocabulary types.
- dsh-bash-local: local subprocesses — bash -c per call in a detached
process group, SIGTERM→SIGKILL group kills, tail-keep truncation with
full-stream spill files, model-friendly env, background task registry.
- dsh-tool-bash: the bash / bash_output / bash_kill tool schemas with
runtime arg validation and background completion notices via
agent.inject(). Non-zero exits are reported, not errored.
Design surveyed against the bash tools of Claude Code, OpenCode, Codex,
and pi (notes in the package READMEs). Permissions/sandbox stay TODO on
the tools/execute waterfall seam; stateful-shell alternatives recorded
in run.ts.
pre-commit: ESLint --fix on staged files (vendored source excluded),
incremental typecheck, and the vendor-manifest guard — any staged
change under vendor/*/src must be accompanied by a vendor/README.md
update in the same commit, mechanizing the local-modification log
discipline. pre-push: tests + hygiene (knip/publint/constraints).
Hooks call the same package.json scripts CI runs (single source of
truth); installed automatically via postinstall.
Flat config with two layers. Correctness (type-checked): the headline
rules for this codebase are no-floating-promises / no-misused-promises
(a lost promise in the agent loop is our primary bug class),
switch-exhaustiveness-check (we switch over merge-extensible unions
everywhere), no-unnecessary-condition, require-await, and
no-explicit-any. Style (@stylistic): 2-space, no semicolons, single
quotes, trailing commas, max-len 140 — the existing house style, now
enforced instead of drifting between agents. vendor/ is excluded
(vendored source keeps upstream style); tests relax the rules that
fight test ergonomics (non-null assertions after expects, async mock
signatures, non-Error throws).
Code adjusted to pass: registry disposers wrap ctx.effect's
promise-returning disposer behind a sync () => void (our public API),
BlockAssembler gains an invariant-checking mustGet instead of non-null
assertions, lastTurnNumber uses findLast, waterfall tails return
Promise.resolve instead of async-without-await arrows, and the two
deliberate suppressions (non-exhaustive derivation switch, unbound
execute pass-through) carry justification comments.
yarn lint / yarn lint:fix added.
Tianyi Cui