refactor(vocab): prune producer-less variants — cache hints, agent source, continuation trigger

The vocabulary maps grow by declaration merging, and the admission policy
stated on TurnEndReasonMap is that a variant lands with its first emitter.
Three declared items had no producer and no consumer:

- CacheHint and the cache?: CacheHint fields on TextBlock/ToolResultBlock:
  nothing constructs a block with cache:, and neither adapter reads .cache —
  DeepSeek prompt caching is automatic (hints map OUT of responses, never IN).
- MessageSourceMap.agent: zero constructors; the subagent backends send the
  parent prompt with no source (logs as user), and the envelope renderer
  interpolates source.kind without routing on it.
- TurnTriggerMap.continuation: the loop structurally cannot emit it —
  continuation is further steps within a turn, never a new turn — and its only
  writer was an llm-replay test fixture that needed any non-message trigger
  (now an injection trigger).

Each variant returns the day it gains a real producer, via the same
merge-extensible maps. Docs updated in the same change: the MessageSourceMap
paste in core.md, the TurnTriggerMap paste in session.md (manifest untouched —
both symbols survive), the content-block vocabulary RFC's cache-hints
consequence line, and the RFC moved to implemented/ and amended to shipped
reality (the image block's own cache field had already left with the
drop-image RFC).
This commit is contained in:
Tianyi Cui
2026-07-04 17:50:50 +08:00
parent 2745879132
commit 3567d000c4
9 changed files with 34 additions and 43 deletions

View File

@@ -16,6 +16,6 @@ In-session context injection (`context/message`, `steering/message`) renders as
## 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](../simplification/2026-07-04-drop-image-content-block.md).
- Reasoning and prefill 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](../simplification/2026-07-04-drop-image-content-block.md). Block cache hints likewise have no core field: DeepSeek prompt caching is automatic, so no shipping adapter can transmit a hint; a caching feature adds a `cache` field together with the adapter that honors it — see [the producer-less-variants RFC](../simplification/2026-07-04-prune-producerless-vocabulary-variants.md).
- 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.