Tianyi Cui
2745879132
ImageBlock had no production producer and every consumer dropped it: the deepseek serializer skipped it, the pi-ai converter skipped it as unrepresentable, the ACP bridge neither advertises image prompt capability nor forwards image blocks, and compact-basic charged a flat 85-token estimate and rendered an [image] placeholder. A block constructed today would silently vanish from the wire — the vocabulary advertised a capability no path honors, the silent-data-loss shape the defensive patterns warn against. The only constructors were tests pinning the skip/estimate branches. Remove ImageBlock and its ContentBlockMap entry (its cache?: CacheHint field leaves with it; CacheHint itself and the other two cache? fields are out of scope). compact-basic loses its explicit image estimate and placeholder arms (the merge-extensible default arms absorb the case); the deepseek serializer, pi-ai converter, and ACP codec already handled image in their default arms, so only their image-naming comments change. The codec's inbound rejection of ACP-protocol image prompt content stays — that guards wire content a client can send regardless of our vocabulary. Tests that constructed harness image blocks to pin the removed branches are dropped (the 85-token estimate pin) or retargeted onto plugin-added block types / other non-text blocks, which the surviving default arms own. Docs, the type-equiv pastes, and the content-block vocabulary RFC's block list and multimodal-home consequence are updated in the same change; the RFC moves to implemented/ and the index is regenerated. A real multimodal feature reintroduces image via declaration merging together with the adapter mapping, ACP advertisement, and compaction pricing that honor it.
2.4 KiB
RFC: Provider-neutral content-block vocabulary owned by dsh-llm
Status: implemented (accepted 2026-06-11)
Context
The harness needs one internal language for messages that the loop, session log, and all plugins speak. Options: mirror the DeepSeek/OpenAI chat-completions shape (zero mapping for the first provider, awkward for rich content), adopt Anthropic's Messages block structure verbatim (battle-tested, but our canonical types would mirror a third-party API we don't target first), or own a vocabulary.
Decision
Own it: messages are arrays of typed content blocks (text, reasoning, tool-call, tool-result), with the union derived from the merge-extensible ContentBlockMap so plugins add block types via declaration merging. The same merge-extensible-map pattern types every "stringly" field (MessageSource, FinishReason, TurnTrigger, TurnEndReason). Streaming is a raw chunk protocol; BlockAssembler is the single shared assembly implementation. Adapters translate to provider wire formats — mapping cost lives in adapters, where it belongs.
In-session context injection (context/message, steering/message) renders as tagged user-role envelopes (the system-reminder pattern) rather than a new role, so adapters carry zero burden. Live-adapter review has since validated the tagged-envelope rendering against current DeepSeek behavior; a future provider-specific mismatch should be handled in that adapter rather than by adding a new role to the canonical content vocabulary.
Consequences
- Reasoning, prefill, and cache hints have a home without provider contortions. Multimodal content deliberately has NO core block type: the core set is limited to blocks every shipping path honors, and a multimodal feature adds its block type through the merge-extensible map in the same coordinated change that maps it in the adapters, surfaces it in the UI bridges, and prices it in compaction — see the drop-image RFC.
- Every adapter pays a translation cost; the first real adapters have since validated the streaming protocol, and new adapters should continue proving their provider-specific mapping in adapter-local tests.
- IDs that cross package boundaries are branded (
CallId,SessionId,AgentId) — nominal typing at zero runtime cost.