Follow up PR #265: refine chapters, diagrams, and add S20 (#283)

* feat: s01-s14 docs quality overhaul — tool pipeline, single-agent, knowledge & resilience

Rewrite code.py and README (zh/en/ja) for s01-s14, each chapter building
incrementally on the previous. Key fixes across chapters:

- s01-s04: agent loop, tool dispatch, permission pipeline, hooks
- s05-s08: todo write, subagent, skill loading, context compact
- s09-s11: memory system, system prompt assembly, error recovery
- s12-s14: task graph, background tasks, cron scheduler

All chapters CC source-verified. Code inherits fixes forward (PROMPT_SECTIONS,
json.dumps cache, real-state context, can_start dep protection, etc.).

* feat: s15-s19 docs quality overhaul — multi-agent platform: teams, protocols, autonomy, worktree, MCP tools

Rewrite code.py and README (zh/en/ja) for s15-s19, the multi-agent platform
chapters. Each chapter inherits all previous fixes and adds one mechanism:

- s15: agent teams (TeamCreate, teammate threads, shared task list)
- s16: team protocols (plan approval, shutdown handshake, consume_inbox)
- s17: autonomous agents (idle polling, auto-claim, consume_lead_inbox)
- s18: worktree isolation (git worktree, bind_task, cwd switching, safety)
- s19: MCP tools (MCPClient, normalize_mcp_name, assemble_tool_pool, no cache)

All appendix source code references verified against CC source. Config priority
corrected: claude.ai < plugin < user < project < local.

* fix: 5 regressions across s05-s19 — glob safety, todo validation, memory extraction, protocol types, dep crash

- s05-s09: glob results now filter with is_relative_to(WORKDIR) (inherited from s02)
- s06-s08: todo_write validates content/status required fields (inherited from s05)
- s09: extract_memories uses pre-compression snapshot instead of compacted messages
- s16: submit_plan docstring clarifies protocol-only (not code-level gate)
- s17-s19: match_response restores type mismatch validation (from s16)
- s17-s19: claim_task deps list handles missing dep files without crashing

* fix: s12 Todo V2 logic reversal, s14/s15 cron range validation, s18/s19 worktree name validation

- s12 README (zh/en/ja): fix Todo V2 direction — interactive defaults to Task,
  non-interactive/SDK defaults to TodoWrite. Fix env var name to
  CLAUDE_CODE_ENABLE_TASKS (not TODO_V2).
- s14/s15: add _validate_cron_field with per-field range checks (minute 0-59,
  hour 0-23, dom 1-31, month 1-12, dow 0-6), step > 0, range lo <= hi.
  Replace old try/except validation that only caught exceptions.
- s18/s19: add validate_worktree_name() to remove_worktree and keep_worktree,
  not just create_worktree.

* fix: align s16-s19 teaching tool consistency

* fix pr265 chapter diagrams

* Add comprehensive s20 harness chapter

* Fix chapter smoke test regressions

* Clarify README tutorial track transition

---------

Co-authored-by: Haoran <bill-billion@outlook.com>
This commit is contained in:
gui-yue
2026-05-20 21:45:38 +08:00
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parent c354cf7721
commit 1baf1aca5a
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# s07: Skill Loading — 用到的时候才加载
[中文](README.md) · [English](README.en.md) · [日本語](README.ja.md)
s01 → s02 → s03 → s04 → s05 → s06 → `s07` → [s08](../s08_context_compact/) → s09 → ... → s20
> *"用到时再加载, 别全塞 prompt 里"* — 通过 tool_result 注入, 不塞 system prompt。
>
> **Harness 层**: 知识 — 按需加载, 不堆满上下文。
---
## 问题
你的项目有一套 React 组件规范、一份 SQL 风格指南、一份 API 设计文档。你希望 Agent 自动遵守这些规范。最直接的想法,全塞进 system prompt
```python
SYSTEM = (
f"You are a coding agent. "
+ open("docs/react-style.md").read() # 2000 行
+ open("docs/sql-style.md").read() # 1500 行
+ open("docs/api-design.md").read() # 3000 行
)
```
6500 行 system prompt。Agent 每次调用 LLM 都带着这些文档——不管是在改 CSS 颜色还是修 SQL 查询。99% 的内容和当前任务无关,白白消耗 token。
---
## 解决方案
![Skill Overview](images/skill-overview.svg)
保留上一章的最小 hook 结构、`todo_write` 和子 Agent本章重点转向新增的 `load_skill` 工具。启动时把技能目录注入 SYSTEM prompt运行时多注册一个工具加载完整内容用到才花 token。
两层设计:
| 层 | 位置 | 时机 | 代价 |
|---|------|------|------|
| 1. 目录 | system prompt | 启动时注入harness 扫描 skills/ | ~100 tokens/skill每轮都带 |
| 2. 内容 | tool_result | Agent 调用 load_skill 时 | ~2000 tokens/skill按需 |
dispatch 机制不变load_skill 通过 `TOOL_HANDLERS[block.name]` 分发。
---
## 工作原理
**skills/ 目录**,每个技能一个子目录,包含 `SKILL.md` 文件:
```
skills/
agent-builder/SKILL.md
code-review/SKILL.md
mcp-builder/SKILL.md
pdf/SKILL.md
```
**第一级:启动时注入目录**harness 启动时调用 `_scan_skills()` 扫描 skills/ 目录,解析每个 SKILL.md 的 YAML frontmatter`name``description`),存入 `SKILL_REGISTRY` 字典。`list_skills()` 从注册表生成目录,注入 SYSTEM prompt。Agent 每轮都能看到"我有哪些技能可用",不花额外 API 调用:
```python
SKILL_REGISTRY: dict[str, dict] = {}
def _scan_skills():
if not SKILLS_DIR.exists():
return
for d in sorted(SKILLS_DIR.iterdir()):
if not d.is_dir():
continue
manifest = d / "SKILL.md"
if manifest.exists():
raw = manifest.read_text()
meta, body = _parse_frontmatter(raw)
name = meta.get("name", d.name)
desc = meta.get("description", raw.split("\n")[0].lstrip("#").strip())
SKILL_REGISTRY[name] = {"name": name, "description": desc, "content": raw}
_scan_skills() # runs once at startup
def list_skills() -> str:
return "\n".join(f"- **{s['name']}**: {s['description']}" for s in SKILL_REGISTRY.values())
def build_system() -> str:
catalog = list_skills()
return (
f"You are a coding agent at {WORKDIR}. "
f"Skills available:\n{catalog}\n"
"Use load_skill to get full details when needed."
)
SYSTEM = build_system()
```
**第二级load_skill**Agent 决定"我需要 SQL 风格指南",调用 `load_skill("sql-style")`。通过注册表查找,不走文件路径,没有路径遍历风险。内容通过 `tool_result` 注入:
```python
def load_skill(name: str) -> str:
skill = SKILL_REGISTRY.get(name)
if not skill:
return f"Skill not found: {name}"
return skill["content"]
```
关键区别:技能内容不是 system prompt 的一部分,它作为一次工具结果进入当前 messages。后续调用会随历史一起携带直到上下文压缩、截断或会话结束。这和 s08 的 compact 自然衔接:按需加载解决了"不该提前带的不要带"compact 解决"该丢的怎么丢"。
---
## 相对 s06 的变更
| 组件 | 之前 (s06) | 之后 (s07) |
|------|-----------|-----------|
| 工具数量 | 7 (bash, read, write, edit, glob, todo_write, task) | 8 (+load_skill) |
| 知识加载 | 无 | 两级:启动时目录注入 SYSTEM + 运行时 load_skill |
| SYSTEM 提示 | 静态字符串 | 启动时扫描 skills/ 注入目录 |
| 技能注册表 | 无 | SKILL_REGISTRY启动时填充防路径遍历 |
| 循环 | 不变 | 不变skill 工具自动分发) |
---
## 试一下
```sh
cd learn-claude-code
python s07_skill_loading/code.py
```
试试这些 prompt
1. `What skills are available?`
2. `Load the code-review skill and follow its instructions`
3. `I need to do a code review -- load the relevant skill first`
观察重点Agent 是否直接从 SYSTEM 里的目录知道有哪些技能?需要完整规范时是否出现 `[HOOK] load_skill`?加载后回答是否使用了对应 skill 的说明?
---
## 接下来
按需加载解决了"不该带的不要带"。但另一个问题来了Agent 连续工作 30 分钟后messages 列表塞满了中间过程。旧的 tool_result、过时的文件内容占着上下文但不产生价值。
s08 Context Compact → 四层压缩策略。便宜的先跑,贵的后跑。
<details>
<summary>深入 CC 源码</summary>
> 以下基于 CC 源码 `loadSkillsDir.ts`、`SkillTool.ts`、`bundledSkills.ts`、`commands.ts` 的分析。
### 一、技能来源:不是只有一个 skills/ 目录
教学版假设所有技能在 `skills/` 目录下。CC 实际从多个来源加载,分布在多个文件中:`loadSkillsDir.ts` 负责从 user/project/`--add-dir` 目录和 legacy commands`.claude/commands/`)加载;`bundledSkills.ts` 负责内置技能;`SkillTool.ts` 处理 MCP 远程技能;`commands.ts` 负责命令聚合。类型包括 managed/policy skills、user skills`~/.claude/skills/`、project skills`.claude/skills/`)、`--add-dir` skills、legacy commands、dynamic skills、conditional skills`paths` frontmatter按文件路径激活、bundled skills、plugin skills、MCP skills。
### 二、SKILL.md Frontmatter 常见字段
CC 的 SKILL.md YAML frontmatter 由 `parseSkillFrontmatterFields()` 解析(`loadSkillsDir.ts`),常见字段包括:
| 字段 | 用途 |
|------|------|
| `name` / `description` | 显示名称和描述 |
| `when_to_use` | 指导模型何时调用 |
| `allowed-tools` | 技能可用工具的自动允许列表 |
| `context` | `inline`(默认)或 `fork`(作为子 Agent 运行) |
| `model` | 模型覆盖haiku/sonnet/opus/inherit |
| `hooks` | 技能级别的 hook 配置 |
| `paths` | 条件激活的 glob 模式 |
| `user-invocable` | 用户可以通过 `/name` 调用 |
完整字段列表随版本迭代会变化,以上仅列出教学版涉及的核心字段。
### 三、两级加载的精确实现
1. **Catalog启动时**`getSkillDirCommands()` 扫描目录 → 注册为 `Command` 对象,只包含元数据。`getSkillListingAttachments()` 把技能列表格式化为附件,预算为上下文窗口的 ~1%(上限 8000 字符)。
2. **Load调用时**:模型调 `Skill` 工具(输入字段是 `skill` + 可选 `args`,教学版用 `name`)→ `getPromptForCommand()` 展开完整 SKILL.md 内容 → `SkillTool` 返回的 tool_result 展示文本只是 `"Launching skill: {name}"`,真正的技能内容通过 `newMessages` 注入对话。教学版把两者合并为"通过 tool_result 注入"是一种简化。
### 教学版的简化是刻意的
- 多文件多来源 → 1 个 `skills/` 目录:足以展示两级加载的核心概念
- 多个 frontmatter 字段 → 只解析 name/description减少解析复杂度
- forked skills`context: 'fork'`)→ 省略:教学版只展开 inline 技能加载
- `Skill` 工具输入 `skill`+`args` → 教学版用 `name`:避免参数解析的额外复杂度
</details>
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