Introduces examples/acp-agent/src/llm-replay.ts, a function/namespace plugin
that installs a single llm/stream waterfall listener. In record mode it tees
the real model's StreamChunks into a per-scenario llm.json (flushed atomically
after EACH stream, since the snapshot subprocess is SIGKILLed and start.ts has
no disposal path). In replay mode it short-circuits the waterfall and serves
recorded streams back positionally — the Nth stream() call gets the Nth entry —
so a snapshot test can drive the real agent with no API key.
Each fixture entry is a discriminated record {chunks|throw|hang} so it can
replay BOTH branches of the LLM failure contract (throw from stream() vs a
finish-error chunk) plus cancellation. A throw entry carries the prefix chunks
emitted before the throw, replayed before the error, so a mid-stream failure
(partial output then STREAM_CLOSED) reproduces what the loop saw live.
Fail-loud on a missing or exhausted fixture (never a silent skip). Unit tests
drive the real LlmService waterfall (record tee, ordered replay, the three
entry kinds, partial-then-throw, fail-loud, event-driven abort, HMR-safety).
Broadens the unit vitest include to examples/*/tests and registers the plugin
+ snapshot tests as knip entries. Per docs/rfc/implemented/2026-06-19.
Vite >=8 warns the plugin is replaceable by the native experimental
resolve.tsconfigPaths option. It isn't for this repo: the native option
applies the nearest tsconfig.json's own paths per importing file, while
our paths map lives only in the root tsconfig — per-workspace tsconfigs
under packages/* and vendor/* have none, so native resolution falls
through to package.json exports (lib/, absent until yarn build) and
every unbuilt test import fails (verified on vite 8.0.16/vitest 4.1.8).
Tianyi Cui
07akioni