765052a7d1
ds-review-bot critical (follow-up): on the first step of a resumed or seeded/forked instance, auto-compaction ran before runStep composed this instance's prefix, so the gate read the PREVIOUS instance's logged prefix from the header fold — a contributor that grew across resume/fork (skills added, AGENTS.md grown: exactly the environment-dependent case) could under-gate and ship an over-window first request. The loop now composes agent/session-prefix before the instance's first agent/pre-step (still once per instance; runStep just reads the cache), and agent/pre-step carries the composed prefix to its listeners. CompactService.compactIfNeeded gains the sessionPrefix parameter; BasicCompactService.estimatePressure gates on the handed value — the header-fold read is gone, so the estimate is exact at every step including a resumed/forked instance's first. Composition moving before the boundary snapshot also means a composing listener's session append now joins the CURRENT request (documented on the seam). New coverage: composition precedes pre-step and the seam receives the composed prefix; cancel and disposal landing inside the composition window drop the step cleanly; the compact gate test hands the prefix directly.
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.