> Core 中立版（Increment 6a 改写，原 deferHard verbatim）。编号与条目结构严格不变（C-2 不变量）；实例术语按 `core/adapters/TERMINOLOGY.md` 绑定。
# Shared Rule — Round-Boundary Context Compaction

> **Canonical source of truth.** This file is the single authoritative copy of
> the round-boundary compaction rule. It is injected **directly** (via
> `<!-- inject -->`) by two skills:
>
> - `review-code/SKILL.md`
> - `review-artifact/SKILL.md`
>
> Both inject tags are resolved by `injectShared`
> (`<harness-package>/src/tool/skill.ts`) at skill-load time. Do not place this
> inject inside a file that is *itself* injected (a nested inject) —
> `injectShared` is single-pass and does not resolve nested inject tags; they
> survive as literal `<!-- inject -->` comments and the procedure is silently
> lost.
>
> **When editing:** update this file only. Every consumer picks up the change
> automatically at load time — do not copy the text into any skill.
>
> This is a reference document, not a skill (no `SKILL.md` frontmatter), so the
> skill loader does not register it. It exists purely so maintainers have one
> place to edit.

## Why a canonical copy exists

Every multi-round review skill (`review-artifact`, `review-code`) needs the model to
read this rule inline at the point it dispatches rounds — a cross-file
reference would not be loaded into the model's context. So the text is
injected directly into both skills at load time. The injection is intentional;
this file exists to keep the two consumers on identical wording without a
copy-paste mirror.

## Canonical text

The block below is what each consumer receives at the inject site. The guard
referenced is the agent-initiated `compact` tool's minimum-turns guard,
configured at `compaction.agent.min_turns_since_compaction` (default **3**).

> **Context compaction (round ≥ 2)**: The Orchestrator is the only long-lived
> context across rounds; per-round dimension outputs, synthesis, and
> convergence tracking must not accumulate unbounded. Once Phase B has posted
> the commit status (all round state persisted in the synthesis comment + commit status)
> and before dispatching the next
> round in Phase A, the Orchestrator MUST run `compact` to summarize the
> conversation through the current round, then re-read
> the latest synthesis comment via `工单评论 API（见 TERMINOLOGY）` to restore
> `current_round` and convergence tracking. The
> Synthesizer's return summary (verdict, per-dimension results, re-audit
> targets) is carried in the compacted conversation; if it was lost, re-read
> the synthesis comment's fenced JSON block as fallback before proceeding.
> Skip on round 1
> (single-pass reviews never loop). Each round then starts from a bounded
> context anchored on file state, not conversation memory.
>
> This round-boundary compaction is mandatory, but it is NOT exempt from the
> `compact` tool's `min_turns_since_compaction` guard
> (`compaction.agent.min_turns_since_compaction`, default 3): no such exemption
> exists in the tool implementation. If the tool rejects with
> `insufficient_turns`, accept the rejection and continue into the next round
> without compacting — do NOT retry or work around the guard. A round with too
> few turns since the last compaction simply keeps its context; the synthesis
> comment + commit status still bound what accumulates.

## Canonical note line

There is no `*(Shared rule …)*` italic note line in any consumer — the inject
directive resolves to this file's full content (this header included) at load
time. Older revisions of this document described a two-step "copy the
canonical text into each mirror" sync procedure; that procedure no longer
exists and must not be reintroduced.