feat(skills): Scope B A2 — 4 竞品生成器注册表+上下文分派+端点接线

注册表 TOOLBOX +4 entry（continue/expand/de-ai/teardown，全 preview-only writes=[]）；
ContextStrategy +with_prior_chapter/text_input；ToolGenerateRequest +text 字段。
toolbox_context 分派新策略（续写→build_continuation_context、原文→build_text_input_context）；
路由续写经 chapter_repo 读最新 accepted/draft 正文注入 builder（core 不 import apps/api，仿 accept_op）。
预览仅 commit ledger 不写业务表（#3）；只声明 tier（#2）；system_prompt 进缓存前缀（#9）。
单测：4 生成器 generate 预览 + 续写读前文/草稿路由 + 扩写/降AI text 路由 + 拆书结构化；
更新 registry/strategy 计数测试（15 工具 / 6 策略）。门禁绿：ruff/format/mypy 196 files/pytest 168(api)+32(skills)。

apps/api/ww_api/routers/toolbox.py

@@ -20,6 +20,7 @@ from typing import Annotated, Any
 from fastapi import APIRouter, Depends, Request
 from sqlalchemy.ext.asyncio import AsyncSession
 from ww_agents import AgentSpec, Conflict, ContinuityReview, continuity_spec
+from ww_core.domain.chapter_repo import ChapterRepo
 from ww_core.domain.outline_write_repo import OutlineWriteRepo
 from ww_core.domain.project_repo import ProjectRepo
 from ww_core.domain.repositories import MemoryRepos, OutlineRepo
@@ -47,6 +48,7 @@ from ww_api.schemas.toolbox import (
 from ww_api.services.credentials import STUB_OWNER_ID
 from ww_api.services.project_deps import (
     TierGatewayBuilder,
+    get_chapter_repo,
     get_memory_repos,
     get_outline_read_repo,
     get_outline_write_repo,
@@ -74,6 +76,7 @@ _INGEST_ERRORS: dict[int | str, dict[str, Any]] = {
 ProjectRepoDep = Annotated[ProjectRepo, Depends(get_project_repo)]
 MemoryReposDep = Annotated[MemoryRepos, Depends(get_memory_repos)]
 OutlineReadRepoDep = Annotated[OutlineRepo, Depends(get_outline_read_repo)]
+ChapterRepoDep = Annotated[ChapterRepo, Depends(get_chapter_repo)]
 WorldWriteRepoDep = Annotated[WorldEntityWriteRepo, Depends(get_world_entity_write_repo)]
 OutlineWriteRepoDep = Annotated[OutlineWriteRepo, Depends(get_outline_write_repo)]
 GatewayBuilderDep = Annotated[TierGatewayBuilder, Depends(get_tier_gateway_builder)]
@@ -138,6 +141,23 @@ async def _chapter_beats(
     return list(raw.get("beats", [])) if isinstance(raw, dict) else []
 
 
+async def _prior_chapter_text(
+    chapter_repo: ChapterRepo, project_id: uuid.UUID, chapter_no: int
+) -> str:
+    """读续写承接的前文正文：优先该章最新 accepted，无则草稿，皆无 → 空串（端点降级）。
+
+    core 的 builder 不 import apps/api——正文在端点读 chapter 领域表后经参数注入
+    （仿链 accept_op 的注入模式），守不变量 #1（DB 为真相源）。
+    """
+    accepted = await chapter_repo.latest_accepted(project_id, chapter_no)
+    if accepted is not None and accepted.content.strip():
+        return accepted.content
+    draft = await chapter_repo.get_draft(project_id, chapter_no)
+    if draft is not None and draft.content.strip():
+        return draft.content
+    return ""
+
+
 @router.post("/projects/{project_id}/skills/{tool_key}/generate", responses=_TOOL_ERRORS)
 async def generate_with_tool(
     project_id: uuid.UUID,
@@ -147,6 +167,7 @@ async def generate_with_tool(
     project_repo: ProjectRepoDep,
     memory: MemoryReposDep,
     outline_repo: OutlineReadRepoDep,
+    chapter_repo: ChapterRepoDep,
     build_gateway: GatewayBuilderDep,
     session: SessionDep,
 ) -> ToolGeneratePreviewResponse:
@@ -170,11 +191,17 @@ async def generate_with_tool(
 
     world_context = ""
     beats: list[str] = []
+    prior_text = ""
     if tool.context_strategy == "with_world":
         world_context = await _world_context(memory, project_id)
     elif tool.context_strategy == "with_outline_chapter":
         chapter_no = body.chapter_no or 1
         beats = await _chapter_beats(outline_repo, project_id, chapter_no)
+    elif tool.context_strategy == "with_prior_chapter":
+        # 续写：端点先读该章最新 accepted/draft 正文（DB 为真相源，#1）+ 该章节拍，注入 builder。
+        chapter_no = body.chapter_no or 1
+        prior_text = await _prior_chapter_text(chapter_repo, project_id, chapter_no)
+        beats = await _chapter_beats(outline_repo, project_id, chapter_no)
 
     context = build_toolbox_context(
         tool.context_strategy,
@@ -183,6 +210,8 @@ async def generate_with_tool(
         world_context=world_context,
         chapter_no=body.chapter_no,
         beats=beats,
+        prior_text=prior_text,
+        text=body.text or "",
     )
 
     gateway = await build_gateway(spec.tier)

apps/api/ww_api/schemas/toolbox.py

@@ -64,8 +64,14 @@ class ToolGenerateRequest(BaseModel):
     """通用生成请求（覆盖全部工具的可选入参；按工具 input_fields 取用，snake_case）。"""
 
     brief: str = Field(default="", description="一句话需求/方向（可空，空则按题材发散）")
+    text: str | None = Field(
+        default=None,
+        description="原文输入（扩写/降AI 的原文、拆书的样本；text_input 策略工具用）",
+    )
     chapter_no: int | None = Field(
-        default=None, ge=MIN_CHAPTER_NO, description="按章展开类工具的章号（开篇/细纲）"
+        default=None,
+        ge=MIN_CHAPTER_NO,
+        description="按章展开/续写类工具的章号（开篇/细纲/续写）",
     )
     count: int | None = Field(default=None, ge=1, le=12, description="生成数量（部分工具可用）")
     kind: str | None = Field(default=None, description="命名对象类别等（部分工具可用）")

apps/api/ww_api/services/toolbox_context.py

@@ -11,14 +11,21 @@ IO（读 projects/world_entities/outline）发生在端点；本模块只负责
 - `brief_only`         ：作品设定（仅标题/题材级）+ 一句话需求；
 - `with_project`       ：作品设定（含前提/主题）+ 一句话需求；
 - `with_world`         ：作品设定 + world_entities 硬规则卡 + 一句话需求；
-- `with_outline_chapter`：作品设定 + 指定章大纲节拍（缺章/缺大纲 → 空节拍，不报错）。
+- `with_outline_chapter`：作品设定 + 指定章大纲节拍（缺章/缺大纲 → 空节拍，不报错）；
+- `with_prior_chapter`  ：作品设定 + 最新已写正文（端点先读 accepted/draft）+ 可选节拍；
+- `text_input`          ：作品设定 + 作者提供的原文（扩写/降AI/拆书样本）+ 一句话需求。
 """
 
 from __future__ import annotations
 
 from collections.abc import Sequence
 
-from ww_core.orchestrator import build_brief_context, build_outline_chapter_context
+from ww_core.orchestrator import (
+    build_brief_context,
+    build_continuation_context,
+    build_outline_chapter_context,
+    build_text_input_context,
+)
 from ww_skills import ContextStrategy
 
 
@@ -30,16 +37,30 @@ def build_toolbox_context(
     world_context: str = "",
     chapter_no: int | None = None,
     beats: Sequence[str] = (),
+    prior_text: str = "",
+    text: str = "",
 ) -> str:
     """据注入策略组装喂网关的文本（PURE，确定性）。
 
     `project_context` 由调用方按策略序列化（brief_only 给精简设定、with_project 给完整设定）；
     `world_context` 仅 with_world 用（已序列化的硬规则卡）；`chapter_no`/`beats` 仅
-    with_outline_chapter 用（缺章/缺大纲时 beats 为空，降级到空节拍而非报错）。
+    with_outline_chapter 用（缺章/缺大纲时 beats 为空，降级到空节拍而非报错）；
+    `prior_text` 仅 with_prior_chapter 用（端点先读最新 accepted/draft 正文注入）；
+    `text` 仅 text_input 用（作者提供的原文样本）。
     """
     if strategy in ("brief_only", "with_project"):
         return build_brief_context(brief=brief, project_context=project_context)
 
+    if strategy == "with_prior_chapter":
+        return build_continuation_context(
+            project_context=project_context,
+            prior_text=prior_text,
+            beats=list(beats) if beats else None,
+        )
+
+    if strategy == "text_input":
+        return build_text_input_context(project_context=project_context, text=text, brief=brief)
+
     if strategy == "with_world":
         base = build_brief_context(brief=brief, project_context=project_context)
         world_block = world_context.strip() or "（暂无世界观设定）"