docs: reserve seam for complete capabilities

packages/compact/compact-basic/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/compact/compact-basic/README.md
-README.md: 5395219147e8932c8e5874e84e534a2c2fe33d53
-README.zh.md: 59479b26c5c8cf27e6ac84814c09f14ecbf9662c
+README.md: e0e3413d42e6afb8e95f91d79f9bdf3a1f17fbda
+README.zh.md: 4515592710f855dc713f078479ebe7c9c7299de1

packages/compact/compact-basic/README.md

@@ -2,9 +2,9 @@
 
 English | [中文](README.zh.md)
 
-The **basic compaction backend**: a `BasicCompactService` implementing the `@deepseek-ai/dsh-compact` seam with reusable `ctx.tokenMeter` pressure, token-budget retention, and summarization as a direct one-shot `ctx.llm.stream()` call that replays the conversation prefix to reuse the provider's KV cache (interceptable at `llm/stream`).
+The **basic compaction backend**: a `BasicCompactService` implementing the `@deepseek-ai/dsh-compact` Service Definition with reusable `ctx.tokenMeter` pressure, token-budget retention, and summarization as a direct one-shot `ctx.llm.stream()` call that replays the conversation prefix to reuse the provider's KV cache (interceptable at `llm/stream`).
 
-This is the implementation tier of the compaction capability — see the [interface package](../compact/README.md) for the seam and the [capability-seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md) for the design.
+This package owns the Service provider role of the compaction capability — see the [Service Definition package](../compact/README.md) for its contract and the [capability-seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md) for the design.
 
 ## What it owns
 
@@ -15,7 +15,7 @@ This backend owns the compaction policy:
 - **Model-free pruning** — after pressure or canonical overflow qualifies, the optional [`ctx.toolResultPrune`](../compact-tool-result-prune/README.md) service rewrites oversized tool results before range selection. Compact-basic remeasures through `ctx.tokenMeter`, skips summarization when pressure becomes safe, and otherwise summarizes the pruned surface. Below-pressure step checks never prune.
 - **Retention** — compact the oldest whole surface units while preserving a recent tail and balanced tool-call/result cuts through the [`dsh-compact` boundary helpers](../compact/README.md#tool-pairing-boundaries). Turn boundaries do not protect old steps inside a runaway turn. An open indivisible tail declines until it closes. The optional pruner can repair an oversized closed tool unit when its text-bearing result is the removable bulk; indivisible non-tool units and non-prunable tool remainders remain out of scope.
 - **Convergence** — retry head-checkpoint compaction up to `compactionRetries`; reject a summary that does not shrink its source, and throw if retries cannot return below threshold.
-- **Summarization** — a direct `llm/stream` call uses the configured provider/model pair and cap, falling back to the latest logged request target and then the agent target, without running the loop-only `agent/request` seam. The call replays the conversation's own system prompt, tools, and shadowed-region messages verbatim and appends the compaction instruction as the final user message, so it reuses the provider's warm prefix cache instead of invalidating it. It sets `GenerateOptions.purpose` to `compaction`, which adapters may forward as request attribution (the DeepSeek adapter sends `x-deepseek-harness-compact: 1`) without touching the model-visible body. Only returned text enters the checkpoint, excluding reasoning and tool calls that would leak private reasoning or create an orphaned call.
+- **Summarization** — a direct `llm/stream` call uses the configured provider/model pair and cap, falling back to the latest logged request target and then the agent target, without running the loop-only `agent/request` extension point. The call replays the conversation's own system prompt, tools, and shadowed-region messages verbatim and appends the compaction instruction as the final user message, so it reuses the provider's warm prefix cache instead of invalidating it. It sets `GenerateOptions.purpose` to `compaction`, which adapters may forward as request attribution (the DeepSeek adapter sends `x-deepseek-harness-compact: 1`) without touching the model-visible body. Only returned text enters the checkpoint, excluding reasoning and tool calls that would leak private reasoning or create an orphaned call.
 - **Framing** — the replacement user message marks established checkpoint context with `<compacted-summary>` tags. The raw summary remains on the `compact/summary` event, and later automatic cycles merge the prior checkpoint.
 - **Lifecycle** — all entry points share one bracket-first region transaction. It validates the range and live lock, appends `compact/start` synchronously, prepares and awaits the summary, revalidates, appends `compact/summary` plus the replacement, and makes exactly one closing attempt. Automatic and explicit-region calls require a numeric open-turn owner and whole-surface stability; the serial `agent/pre-step` listener checks pressure before request derivation, while canonical provider overflow enters through `agent/request-error` and authorizes retry only after durable surface progress. `compactNow()` reserves idle admission, uses `turn: null`, accepts append-only context outside its selected span, flushes every closed attempt, and releases admission in `finally`.
 - **Overflow recovery** — provider-confirmed overflow needs no capacity metadata: it bypasses normal pressure and retention, prunes, then attempts one maximal balanced head reduction while leaving the newest indivisible unit. Retry is authorized whenever `surface.replaceGeneration` advances, including when pruning lands before later summary work throws. No replacement, an exhausted target-specific cap, cancellation, or an unknown/noncanonical error preserves the original provider failure.

packages/compact/compact-basic/README.zh.md

@@ -2,9 +2,9 @@
 
 [English](README.md) | 中文
 
-**基础压缩（compaction）后端**：`BasicCompactService` 实现 `@deepseek-ai/dsh-compact` seam，使用可复用的 `ctx.tokenMeter` 压力、token 预算保留与摘要。摘要是直接的一次性 `ctx.llm.stream()` 调用，它会回放会话前缀以复用提供方的 KV Cache（可在 `llm/stream` 处拦截）。
+**基础压缩（compaction）后端**：`BasicCompactService` 实现 `@deepseek-ai/dsh-compact` Service Definition，使用可复用的 `ctx.tokenMeter` 压力、token 预算保留与摘要。摘要是直接的一次性 `ctx.llm.stream()` 调用，它会回放会话前缀以复用提供方的 KV Cache（可在 `llm/stream` 处拦截）。
 
-这是压缩能力的实现层。seam 见 [接口包](../compact/README.md)，设计见 [能力 seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md)。
+本包承担压缩能力的 Service provider 角色；其约定见 [Service Definition 包](../compact/README.md)，设计见 [能力 seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md)。
 
 ## 拥有的职责
 
@@ -15,7 +15,7 @@
 - **不依赖模型的剪枝**：在压力或规范溢出符合条件后，可选的 [`ctx.toolResultPrune`](../compact-tool-result-prune/README.md) 服务会在选择范围之前改写超大工具结果。Compact-basic 通过 `ctx.tokenMeter` 重新测量；如果压力已回到安全范围，就跳过摘要，否则对已剪枝的表层进行摘要。低于压力的步骤检查绝不剪枝。
 - **保留**：压缩最旧的完整表层单元，同时保留近期尾部，并通过 [`dsh-compact` 边界 helper](../compact/README.md#tool-pairing-boundaries) 将切分点调整到工具调用／结果配对平衡的位置。轮次边界不会保护失控轮次内的旧步骤。尚未闭合且不可分的尾部会在闭合前拒绝压缩。当闭合的超大工具单元以文本型结果为可移除主体时，可选 pruner 可以修复它；不可分的非工具单元与不可剪枝的工具剩余部分不在范围内。
 - **收敛**：最多按 `compactionRetries` 重试头部检查点压缩；拒绝不能缩小源内容的摘要，如果重试仍无法回到阈值以下，则抛出异常。
-- **摘要**：直接 `llm/stream` 调用使用已配置的提供方／模型对与上限，回退到最新已记录请求目标，然后再回退到 agent 目标，而不运行仅用于 agent loop 的 `agent/request` seam。该调用会逐字回放会话自身的系统提示词、工具与已遮蔽区域消息，并将压缩指令作为最后一条 user 消息追加，从而复用提供方的热前缀 cache，而非使它失效。它将 `GenerateOptions.purpose` 设为 `compaction`，适配器可将其作为请求归因转发（DeepSeek 适配器发送 `x-deepseek-harness-compact: 1`），但不会触碰模型可见的请求体。只有返回的文本会进入检查点；推理（reasoning）和工具调用都会被排除，以免泄露私有推理或产生遗留调用。
+- **摘要**：直接 `llm/stream` 调用使用已配置的提供方／模型对与上限，回退到最新已记录请求目标，然后再回退到 agent 目标，而不运行仅用于 agent loop 的 `agent/request` 扩展点。该调用会逐字回放会话自身的系统提示词、工具与已遮蔽区域消息，并将压缩指令作为最后一条 user 消息追加，从而复用提供方的热前缀 cache，而非使它失效。它将 `GenerateOptions.purpose` 设为 `compaction`，适配器可将其作为请求归因转发（DeepSeek 适配器发送 `x-deepseek-harness-compact: 1`），但不会触碰模型可见的请求体。只有返回的文本会进入检查点；推理（reasoning）和工具调用都会被排除，以免泄露私有推理或产生遗留调用。
 - **框定**：替换 user 消息使用 `<compacted-summary>` 标签标记已建立的检查点上下文。原始摘要保留在 `compact/summary` 事件上，后续自动周期会合并之前的检查点。
 - **生命周期**：所有入口点共享一个先记录标记的区域事务。它会验证范围与活动锁，同步追加 `compact/start`，准备并等待摘要，重新验证，再追加 `compact/summary` 和替换，最后恰好进行一次闭合尝试。自动调用和显式范围调用要求数字标识的开放轮次归属，并要求整个表层保持稳定；串行 `agent/pre-step` listener 会在派生请求之前检查压力，而规范提供方溢出则经由 `agent/request-error` 进入，并且只在表层取得持久进展后才允许重试。`compactNow()` 会预留空闲接纳，使用 `turn: null`，允许所选 span 之外追加仅追加上下文，flush 每次已闭合尝试，并在 `finally` 中释放接纳预留。
 - **溢出恢复**：提供方已确认的溢出不需容量元数据。它会绕过常规压力与保留，执行剪枝，再尝试一次最大平衡头部缩减，并留下最新不可分单元。只要 `surface.replaceGeneration` 前进，就允许重试，包括剪枝在后续摘要工作抛出异常前已落地的情况。如果没有替换、目标特定上限已耗尽、已取消，或遇到未知／非规范错误，则保留原始提供方失败。