Tianyi Cui
605587e79c
Add a second axis to every RFC — its class (feature, bug-fix,
simplification, architecture, process, testing) — encoded in the path
as docs/rfc/{lifecycle}/{class}/file.md. The folder is the label, so
the closed set is enforced by structure rather than a parsed field.
Two new doc-sync gates back it:
- verify-rfc-classification: every RFC sits in a valid class folder and
the README index lists it under the matching lifecycle→class heading.
- verify-doc-refs: every docs/*.md path cited in a packages|examples TS
comment resolves — closes a drift class verify-md-links can't see, and
catches the four comment refs this reorg moved.
The README gains a Classification section explaining the taxonomy and
per-class index sub-sections. A self-referential process RFC records why
the scheme is path-encoded and gated.
2.9 KiB
RFC: Two LLM adapters as a design-verification twin
Status: implemented (accepted 2026-06-13)
Context
dsh-llm owns a provider-neutral streaming vocabulary — the StreamChunk protocol (block-start, text-delta, reasoning-delta, tool-call-delta, block-end, usage, finish) and the content-block types (the content-block vocabulary). A vocabulary defined against a single adapter risks baking that adapter's quirks into the "neutral" contract: anything the one implementation happens to do becomes the de-facto spec, and the abstraction is unverified until a second provider arrives — by which point the leak is expensive to fix.
Decision
Ship two adapters against the one contract from the start, deliberately built on different internals:
dsh-llm-deepseek— hand-rolledfetch+ SSE parsing against the DeepSeek API.dsh-llm-pi-ai— the same endpoint through the@earendil-works/pi-ailibrary (its own event vocabulary).
The rule they enforce: anything the StreamChunk vocabulary cannot express for BOTH implementations is a core-vocabulary bug, caught immediately rather than at the next provider. The pair pinned down conventions now documented on StreamChunk in dsh-llm/src/types.ts: usage emitted before finish, nothing after finish, tool-call arguments as raw JSON strings end-to-end, and the two sanctioned error paths (throw from stream() or end with finish {kind:'error'|'aborted'}) that a consumer must handle on both sides — a divergence the library-backed adapter surfaced that a single hand-rolled adapter would have hidden.
Alternatives considered: a single adapter — less code and half the e2e cost, but leaves the "provider-neutral" claim unverified; the vocabulary would encode DeepSeek-via-fetch assumptions silently. A mock second adapter — cheaper but doesn't exercise a real provider's wire quirks, so it proves little. The twin is real-on-real.
Consequences
Double the adapter maintenance and double the key-gated e2e surface (both adapters cover V4 Flash and Pro across representative thinking/effort modes). Bought: a continuously-verified neutrality guarantee for the most leak-prone abstraction in the codebase, and a worked second example for adapter authors. The two share the core Config shape (apiKey/baseURL/models) so a deployment swaps mostly one line, but the reasoning knob differs — dsh-llm-deepseek takes thinking/reasoningEffort, dsh-llm-pi-ai takes a single reasoning level — so a swap translates that field. If the maintenance cost ever outweighs the verification value (e.g. once conformance tests from architectural conformance cover the contract mechanically), retiring the twin to a single adapter + the conformance kit would be a new RFC superseding this one.