e6bd6cc9be
ds-review-bot critical: compactIfNeeded estimated pressure from the derived history + system prompt only, but every loop-built request also carries EpochHeader.messagePrefix in front of the history — a deployment at the window edge would under-estimate by exactly the prefix, skip compaction, and ship an over-window request. BasicCompactService now gates on estimatePressure(): the session prefix read from the log's folded header + the derived history + the system prompt. The fold is exact from the instance's second request on (and from a resumed instance's first — the previous instance logged its prefix); it is absent only before a fresh session's first request, where the history is a single prompt and compaction is moot. Compaction itself still shrinks history only — a prefix that alone approaches the window is a configuration error no compactor fixes, same as the documented single-unit-overflow stance.
compact/ — compaction capability family
A three-package capability seam (see capability seams): an abstract compaction interface, a backend that summarizes, and the model-facing tool that consumes it. The interface and a first backend (compact-basic/) exist; the consumer tool is deferred. All product packages.
| Package | Role | ctx key |
|---|---|---|
compact/ |
Abstract compaction seam (interface + compact/* events + CompactionResult) |
ctx.compact |
compact-basic/ |
A backend: chars-per-token estimation (charsPerToken, default 4) + token-budget retention + llm.stream() summarization |
(registers ctx.compact) |
tool-compact/ (deferred) |
Model-facing /compact tool over ctx.compact |
(registers on ctx.tools) |
The interface lives at compact/compact/, the backend at compact/compact-basic/. Unlike the bash seam, it depends on dsh-session and dsh-llm — its verbs are defined over a Session and its output is the ContentBlock vocabulary, so the contract cannot be expressed without naming them. That deviation from the "interface depends only on cordis" guidance is intentional and recorded in the compaction capability-seam RFC. A tokenizer- or template-based backend would replace compact-basic without touching the interface or the tool.