Complete rewrite

.dockerignore

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+.git
+node_modules
+dist
+*.tsbuildinfo
+bun.lock
+bench-results*.jsonl
+bench-results*.json
+.pi*
+research
+docs

AGENTS.md

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+# AGENTS.md
+
+## Project North Star
+
+`pi-vcc` is an algorithmic conversation compactor for Pi. Its goal is not merely to make summaries shorter; it is to maximize expected continuation value after compaction.
+
+Optimize compaction across these objectives:
+
+1. **Recall fidelity** — important goals, constraints, files, identifiers, evidence handles, decisions, blockers, and next actions remain available either in active context or recall.
+2. **Semantic coherence** — the compacted state should let the agent understand what is happening, why it matters, and what to do next.
+3. **Post-compaction working room** — active prompt state should stay compact enough to leave useful room for future work.
+4. **Retrieval dependence** — bulky or older detail may move out of active context only when it remains recoverable through transcript, recall, files, or artifacts.
+5. **Cache preservation** — stable prompt prefixes should remain byte/token stable across ordinary compactions; volatile updates should be isolated into late recent/volatile sections.
+
+A shorter summary is not better if it loses continuity, exact identifiers, recoverability, or cache reuse.
+
+## Compaction Design Principles
+
+- Prefer stable structured state over full-summary rewrites.
+- Keep durable facts before volatile facts.
+- Keep volatile updates in explicit recent/volatile sections.
+- Preserve exact paths, identifiers, error signatures, request IDs, span/probe IDs, and commit references when they are relevant evidence.
+- Offload bulky re-fetchable details to recall/history with pointers rather than active prompt bodies.
+- Separate current truth from historical transcript. Stale or corrected facts may remain recallable, but must not remain current guidance.
+- Treat prompt-cache churn as a first-class performance and cost concern.
+
+## Current Cache-Aware Layout
+
+Stable/current sections should remain as stable as possible:
+
+```text
+Session Goal
+Files And Changes
+Commits
+Evidence Handles
+User Preferences
+Current Scope
+```
+
+Recent/volatile sections may change more often and should stay bounded:
+
+```text
+Recent Commits
+Recent Scope Updates
+Recent User Preferences
+Recent Evidence Handles
+Outstanding Context
+Brief Transcript
+Kept Raw Tail
+```
+
+Do not move volatile content back into stable sections without benchmark-backed evidence.
+
+## Benchmarking Expectations
+
+Use the Docker benchmark path as the primary validation route:
+
+```bash
+docker build -t pi-vcc-bench .
+docker run --rm pi-vcc-bench --compactors pi-vcc --assert
+docker run --rm pi-vcc-bench --compactors pi-vcc --assert-cache
+```
+
+For original-vs-current comparisons:
+
+```bash
+node scripts/compare-compaction-refs.mjs \
+  --baseline 53dc551 \
+  --head HEAD \
+  --compactors pi-vcc \
+  --out /tmp/pi-vcc-compaction-compare
+```
+
+For real-session cache behavior:
+
+```bash
+node scripts/compare-compaction-refs.mjs \
+  --baseline 53dc551 \
+  --head HEAD \
+  --compactors pi-vcc \
+  --real-only \
+  --real-sessions-dir ~/.pi/agent/sessions \
+  --real-limit 5 \
+  --show-layer-diff \
+  --out /tmp/pi-vcc-real-compare
+```
+
+## Interpreting Results
+
+Good changes should generally:
+
+- preserve or improve correctness assertions
+- preserve or improve cache-boundary assertions
+- move `firstChangedPromptLayer` later, not earlier
+- increase stable-prefix tokens for repeated compactions
+- avoid growing full prompt tokens unless the added state is justified
+- keep recent/volatile sections bounded
+
+If a change improves one metric while hurting another, judge it by expected continuation value, not by any single metric alone.
+
+## Development Guidance
+
+- Add a focused RED probe before or alongside compaction behavior changes.
+- Keep synthetic probes for exact correctness and cache-boundary behavior.
+- Use real-session replay to find outliers and avoid overfitting synthetic cases.
+- Prefer small semantic commits that can be reviewed and reverted independently.
+- Do not claim cache improvements without fresh benchmark evidence.

Dockerfile

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+# syntax=docker/dockerfile:1
+
+# renovate: datasource=docker depName=oven/bun versioning=semver
+ARG BUN_VERSION=1.3.13
+
+FROM oven/bun:${BUN_VERSION} AS source
+WORKDIR /app
+
+COPY --link package.json README.md index.ts ./
+COPY --link src ./src
+COPY --link bench ./bench
+COPY --link scripts ./scripts
+
+FROM oven/bun:${BUN_VERSION} AS final
+ENV NODE_ENV=production
+
+COPY --link --from=source --chown=1000:1000 /app /app
+WORKDIR /app
+USER bun
+
+ENTRYPOINT ["bun", "scripts/bench-compaction.ts"]
+CMD ["--jsonl"]