diff --git a/.agents/skills/jsdoc/SKILL.md b/.agents/skills/jsdoc/SKILL.md
new file mode 100644
index 0000000..6b4b151
--- /dev/null
+++ b/.agents/skills/jsdoc/SKILL.md
@@ -0,0 +1,237 @@
+---
+name: jsdoc
+description: Guidelines for writing minimal, high-quality JSDoc comments in TypeScript.
+---
+
+# JSDoc Skill
+
+This skill provides focused guidelines for writing JSDoc comments consistently across the codebase.
+
+## When to Use
+
+- Documenting exported type properties and configuration options
+- Adding context that TypeScript types don't convey on their own
+- Providing usage examples for non-obvious or multi-variant APIs
+- Writing inline documentation for generated docs
+
+## What It Does
+
+- Defines `@example` format conventions (label + inline backtick or fenced block)
+- Ensures every exported type and property has meaningful documentation
+- Avoids redundant tags that duplicate TypeScript type information
+- Ensures consistent documentation style across all packages
+
+---
+
+## `@example` Format
+
+### Short one-liner — label on the `@example` line, code as inline backtick on the next line
+
+```typescript
+/**
+ * @example Required parameter
+ * `name: Type`
+ *
+ * @example Optional parameter
+ * `name?: Type`
+ */
+```
+
+### Multi-line — fenced code block immediately after `@example`
+
+````typescript
+/**
+ * @example
+ * ```ts
+ * const result = buildParams(node, {
+ *   paramsType: 'inline',
+ * })
+ * ```
+ */
+````
+
+### Multiple variants — use multiple `@example` blocks
+
+```typescript
+/**
+ * @example Object mode
+ * `{ id, data, params }: { id: string; data: Data; params?: QueryParams }`
+ *
+ * @example Inline mode
+ * `id: string, data: Data, params?: QueryParams`
+ */
+```
+
+### Rules
+
+| Rule                    | ✅ Correct                          | ❌ Incorrect                                 |
+| ----------------------- | ----------------------------------- | -------------------------------------------- |
+| Label + inline code     | `@example Required\n\`name: Type\`` | `@example \`name: Type\`` (code on tag line) |
+| Multi-line code         | Fenced ` ```ts ``` ` block          | Bare code lines without a fence              |
+| Short examples          | Inline backtick                     | Triple-backtick fence (too heavy)            |
+| One concern per example | Separate `@example` blocks          | One example covering all cases               |
+
+---
+
+## Tags
+
+### Use Frequently
+
+| Tag           | Purpose            | Notes                                                  |
+| ------------- | ------------------ | ------------------------------------------------------ |
+| `@default`    | Default value      | Only when default is non-obvious; omit for `undefined` |
+| `@example`    | Usage example      | Prefer for complex or multi-variant APIs               |
+| `@note`       | Important caveat   | Version info, breaking changes                         |
+| `@deprecated` | Mark as deprecated | Include migration path                                 |
+
+### Use Sparingly
+
+| Tag         | Purpose                 |
+| ----------- | ----------------------- |
+| `@see`      | Reference external docs |
+| `@internal` | Internal API            |
+| `@beta`     | Experimental            |
+
+### Avoid (TypeScript Provides)
+
+- ❌ `@param` — use TypeScript parameter types
+- ❌ `@returns` — use TypeScript return type
+- ❌ `@type` — use TypeScript type annotation
+- ❌ `@typedef` — use `type` or `interface`
+- ❌ `@default undefined` — optional (`?`) already implies this
+
+---
+
+## Documentation Patterns
+
+### Simple property — always multi-line
+
+```typescript
+/**
+ * Output directory for generated files.
+ */
+outDir?: string
+```
+
+> ❌ Never use single-line `/** description */` — always expand to multi-line.
+
+### Property with non-obvious default
+
+```typescript
+/**
+ * Maximum number of concurrent callbacks during traversal.
+ * Higher values overlap I/O-bound work; lower values reduce memory pressure.
+ *
+ * @default 30
+ */
+concurrency?: number
+```
+
+> Do **not** add `@default false` or `@default undefined` when the TypeScript type already makes the default obvious.
+
+### Enum / union with options
+
+```typescript
+/**
+ * How path parameters are emitted in the function signature.
+ * - `'object'` groups them as a single destructured parameter
+ * - `'inline'` spreads them as individual parameters
+ * - `'inlineSpread'` emits a single rest parameter
+ */
+pathParamsType: 'object' | 'inline' | 'inlineSpread'
+```
+
+### Property with example
+
+```typescript
+/**
+ * Applies a uniform transformation to every resolved type string.
+ * Use this for framework-level type wrappers.
+ *
+ * @example Wrap every type in a reactive container
+ * `typeWrapper: (t) => \`Reactive<${t}>\``
+ */
+typeWrapper?: (type: string) => string
+```
+
+### Nested properties — every field gets its own multi-line JSDoc
+
+```typescript
+names?: {
+  /**
+   * Name for the request body parameter.
+   * @default 'data'
+   */
+  data?: string
+  /**
+   * Name for the query parameters group parameter.
+   * @default 'params'
+   */
+  params?: string
+  /**
+   * Name for the header parameters group parameter.
+   * @default 'headers'
+   */
+  headers?: string
+}
+```
+
+### Function documentation
+
+Only add JSDoc when it adds value beyond the signature:
+
+```typescript
+// ✅ No JSDoc needed — signature is self-explanatory
+function camelCase(str: string): string { ... }
+
+// ✅ JSDoc adds value — explains behaviour and non-obvious edge cases
+/**
+ * Returns `true` when the schema resolves to a plain string output.
+ *
+ * - `string`, `uuid`, `email`, `url`, `datetime` are always plain strings.
+ * - `date` and `time` are plain strings when their `representation` is `'string'`.
+ *
+ * @example UUID resolves to a plain string
+ * `isStringType(uuidSchema) // true`
+ *
+ * @example Date with date representation is not a plain string
+ * `isStringType(dateSchema) // false`
+ */
+function isStringType(node: SchemaNode): boolean { ... }
+```
+
+---
+
+## Guidelines
+
+**✅ DO:**
+
+- Document **what** the property does, not its TypeScript type
+- Give every exported type, property, and function a JSDoc comment
+- Always use multi-line JSDoc blocks — never single-line `/** ... */`
+- Use concrete, full-sentence descriptions — not "Enum schema." or "Boolean value."
+- Include `@default` only when the default is non-obvious (not `undefined`, not `false`)
+- Use multiple `@example` blocks to show different variants or modes
+- Keep `@example` labels short and descriptive
+
+**❌ DON'T:**
+
+- Write single-line `/** description */` — always use multi-line
+- Write `@default undefined` — optional `?` already implies this
+- Put code directly on the `@example` line: `@example \`foo: string\`` → move code to next line
+- Use `@param` or `@returns` tags
+- Over-document trivial, self-explanatory properties
+
+---
+
+## Tag Order
+
+For consistency, use this order within a JSDoc block:
+
+1. Description (required)
+2. Bullet-list of variants or behaviours (if applicable)
+3. `@default` (if non-obvious)
+4. `@example` (one or more)
+5. `@note` (if needed)
+6. `@deprecated` (if applicable)
+7. `@see` (if providing references)
diff --git a/AGENTS.md b/AGENTS.md
index 4616d78..96320f9 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -113,6 +113,14 @@ packages/result      # output
 - 不要讓 agent 修改 `prototype/`、`frontend/`、`backend/` 原始輸入資料夾；生成與執行 artifact 應限制在 `output/` 與 `.ht/`。
 - 保持 MVP 邊界，避免加泛用抽象或一開始支援所有 monorepo 形態。
 
+## JSDoc 原則
+
+- 依專案的 `jsdoc` skill 撰寫 JSDoc；這裡只補充 HTML Transform 專案特有規則。
+- JavaScript 的 JSDoc 優先補在 exported API、stage 入口、跨模組 helper，或描述非顯而易見契約與限制的位置；不為測試檔或區域性小函式刻意補註解。
+- JSDoc 使用繁體中文，並把說明重點放在 artifact、pipeline stage、MVP 限制、cache/placeholder 行為、輸入輸出契約等專案脈絡。
+- 不新增 `jsdoc` 產生 HTML 文件的設定、script 或 build step，除非使用者明確要求。
+- 補 JSDoc 不應順手 refactor、改行為、加抽象或擴大 scope。
+
 ## 驗證
 
 完成任何改動後至少執行：
diff --git a/src/index.js b/src/index.js
index 64972ce..eb2519b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,4 +1,9 @@
+/**
+ * 提供 `ht.config.*` 使用的設定包裝器，讓使用者能保留日後型別提示的入口。
+ *
+ * @param {object} config 使用者提供的 HTML Transform 設定。
+ * @returns {object} 原樣回傳的設定物件。
+ */
 export function defineConfig(config) {
   return config
 }
-
diff --git a/src/lib/agent.js b/src/lib/agent.js
index 8ae1f74..d1f1e15 100644
--- a/src/lib/agent.js
+++ b/src/lib/agent.js
@@ -6,10 +6,22 @@ const commands = {
   gemini: ['gemini']
 }
 
+/**
+ * 將設定中的 agent 名稱解析成可執行命令。
+ *
+ * @param {string} agent `ht.config.*` 中的 agent 名稱。
+ * @returns {string[]} 命令與預設參數。
+ */
 export function resolveAgentCommand(agent) {
   return commands[agent] ?? [agent]
 }
 
+/**
+ * 檢查命令是否能從目前 shell PATH 找到。
+ *
+ * @param {string} command 要檢查的可執行檔名稱。
+ * @returns {Promise<boolean>} 找得到命令時為 `true`。
+ */
 export async function commandExists(command) {
   return new Promise((resolve) => {
     const child = spawn('which', [command], { stdio: 'ignore' })
@@ -17,4 +29,3 @@ export async function commandExists(command) {
     child.on('error', () => resolve(false))
   })
 }
-
diff --git a/src/lib/config.js b/src/lib/config.js
index 643fc72..69e3f7e 100644
--- a/src/lib/config.js
+++ b/src/lib/config.js
@@ -36,6 +36,12 @@ const defaultConfig = {
   }
 }
 
+/**
+ * 從專案根目錄載入 `ht.config.*`，並補齊 CLI pipeline 需要的預設路徑與 stage 設定。
+ *
+ * @param {string} cwd 要搜尋設定檔的工作目錄。
+ * @returns {Promise<object>} 正規化後的設定物件，包含解析後的絕對路徑。
+ */
 export async function loadConfig(cwd = process.cwd()) {
   const candidates = ['ht.config.mjs', 'ht.config.js', 'ht.config.json', 'ht.config.ts']
   for (const filename of candidates) {
@@ -88,4 +94,3 @@ function normalizeConfig(config, cwd) {
     htDir: resolve(cwd, '.ht')
   }
 }
-
diff --git a/src/lib/files.js b/src/lib/files.js
index d3dbe56..d0101eb 100644
--- a/src/lib/files.js
+++ b/src/lib/files.js
@@ -2,24 +2,56 @@ import { mkdir, readFile, readdir, stat, writeFile } from 'node:fs/promises'
 import { createHash } from 'node:crypto'
 import { dirname, extname, join, relative } from 'node:path'
 
+/**
+ * 確保資料夾存在，供 stage 在寫入 `.ht/` 與 output artifact 前使用。
+ *
+ * @param {string} path 要建立的資料夾路徑。
+ * @returns {Promise<void>}
+ */
 export async function ensureDir(path) {
   await mkdir(path, { recursive: true })
 }
 
+/**
+ * 以穩定格式寫入 JSON artifact。
+ *
+ * @param {string} path 輸出檔案路徑。
+ * @param {unknown} data 要序列化的資料。
+ * @returns {Promise<void>}
+ */
 export async function writeJson(path, data) {
   await ensureDir(dirname(path))
   await writeFile(path, `${JSON.stringify(data, null, 2)}\n`)
 }
 
+/**
+ * 讀取 JSON artifact。
+ *
+ * @param {string} path JSON 檔案路徑。
+ * @returns {Promise<unknown>} 解析後的 JSON 值。
+ */
 export async function readJson(path) {
   return JSON.parse(await readFile(path, 'utf8'))
 }
 
+/**
+ * 計算檔案內容雜湊，供 prototype cache 判斷是否命中。
+ *
+ * @param {string} path 檔案路徑。
+ * @returns {Promise<string>} 十六進位 SHA-256 digest。
+ */
 export async function sha256File(path) {
   const content = await readFile(path)
   return createHash('sha256').update(content).digest('hex')
 }
 
+/**
+ * 遞迴列出資料夾內檔案，缺少資料夾時回傳空陣列以符合 MVP doctor/scan 行為。
+ *
+ * @param {string} root 搜尋根目錄。
+ * @param {string[]} extensions 要保留的副檔名；空陣列代表不過濾。
+ * @returns {Promise<string[]>} 依字典序排序的檔案路徑。
+ */
 export async function listFiles(root, extensions = []) {
   const output = []
   async function walk(dir) {
@@ -39,6 +71,12 @@ export async function listFiles(root, extensions = []) {
   return output.sort()
 }
 
+/**
+ * 檢查路徑是否存在。
+ *
+ * @param {string} path 要檢查的路徑。
+ * @returns {Promise<boolean>} 路徑存在時為 `true`。
+ */
 export async function exists(path) {
   try {
     await stat(path)
@@ -48,7 +86,13 @@ export async function exists(path) {
   }
 }
 
+/**
+ * 將輸入檔路徑轉成 `.ht/` artifact 使用的穩定相對名稱。
+ *
+ * @param {string} root 輸入根目錄。
+ * @param {string} file 輸入檔案路徑。
+ * @returns {string} 去除 `.html` 副檔名並標準化分隔符的 artifact 名稱。
+ */
 export function artifactPath(root, file) {
   return relative(root, file).replaceAll('\\', '/').replace(/\.html$/i, '')
 }
-
diff --git a/src/lib/html.js b/src/lib/html.js
index 76d0dc3..ded90fb 100644
--- a/src/lib/html.js
+++ b/src/lib/html.js
@@ -1,3 +1,9 @@
+/**
+ * 從 HTML source 萃取 deterministic summary，作為 MVP 階段替代 browser snapshot 的 evidence。
+ *
+ * @param {string} html HTML source。
+ * @returns {object} 頁面標題、文字、表單欄位與互動元素摘要。
+ */
 export function summarizeHtml(html) {
   const title = matchText(html, /<title[^>]*>([\s\S]*?)<\/title>/i)
   const headings = collect(html, /<h([1-6])[^>]*>([\s\S]*?)<\/h\1>/gi).map((item) => cleanText(item[2]))
@@ -15,6 +21,12 @@ export function summarizeHtml(html) {
   return { title, headings, buttons, labels, inputs, textSamples }
 }
 
+/**
+ * 依 semantic landmark 將 HTML source 拆成可追蹤的頁面區塊。
+ *
+ * @param {string} html HTML source。
+ * @returns {Array<object>} 區塊清單；找不到 landmark 時會回傳單一 `main` 區塊。
+ */
 export function extractRegions(html) {
   const landmarks = [
     ['header', /<header\b[^>]*>([\s\S]*?)<\/header>/gi, 'banner'],
@@ -50,6 +62,12 @@ export function extractRegions(html) {
   return regions
 }
 
+/**
+ * 取出 MVP pipeline 可用於比對與生成的可見文字樣本。
+ *
+ * @param {string} html HTML source。
+ * @returns {string[]} 去除 script、style 與標籤後的文字 token。
+ */
 export function visibleText(html) {
   const withoutScripts = html
     .replace(/<script\b[\s\S]*?<\/script>/gi, ' ')
@@ -66,6 +84,12 @@ export function visibleText(html) {
     .slice(0, 50)
 }
 
+/**
+ * 將 deterministic region evidence 轉成目前 MVP 使用的 Vuetify-oriented RegionSpec。
+ *
+ * @param {object} region `extractRegions` 產生的區塊。
+ * @returns {object} 後續 plan/run stage 使用的 RegionSpec。
+ */
 export function inferRegionSpec(region) {
   const summary = summarizeHtml(region.html)
   const hasForm = /<(form|input|select|textarea)\b/i.test(region.html)
diff --git a/src/lib/playwright-cli.js b/src/lib/playwright-cli.js
index d562e2c..f578803 100644
--- a/src/lib/playwright-cli.js
+++ b/src/lib/playwright-cli.js
@@ -3,6 +3,12 @@ import { join } from 'node:path'
 import { exists } from './files.js'
 import { commandExists } from './agent.js'
 
+/**
+ * 依專案規則解析 Playwright CLI，不依賴使用者全域環境作為第一選擇。
+ *
+ * @param {string} cwd 專案工作目錄。
+ * @returns {Promise<object | null>} 可執行命令、參數與來源；找不到時為 `null`。
+ */
 export async function resolvePlaywrightCli(cwd = process.cwd()) {
   const localBin = join(cwd, 'node_modules/.bin/playwright-cli')
   if (await exists(localBin)) return { command: localBin, args: [], source: 'local' }
@@ -11,6 +17,12 @@ export async function resolvePlaywrightCli(cwd = process.cwd()) {
   return null
 }
 
+/**
+ * 確認解析到的 Playwright CLI 能實際執行。
+ *
+ * @param {string} cwd 專案工作目錄。
+ * @returns {Promise<boolean>} `playwright-cli --version` 成功時為 `true`。
+ */
 export async function playwrightCliAvailable(cwd = process.cwd()) {
   const resolved = await resolvePlaywrightCli(cwd)
   if (!resolved) return false
@@ -20,4 +32,3 @@ export async function playwrightCliAvailable(cwd = process.cwd()) {
     child.on('error', () => resolve(false))
   })
 }
-
diff --git a/src/stages/diff.js b/src/stages/diff.js
index 8d02b23..74de719 100644
--- a/src/stages/diff.js
+++ b/src/stages/diff.js
@@ -3,6 +3,11 @@ import { join } from 'node:path'
 import { loadConfig } from '../lib/config.js'
 import { ensureDir, listFiles, readJson } from '../lib/files.js'
 
+/**
+ * 執行 Stage 4：依現有 LayoutSpec 產生 deterministic placeholder diff report。
+ *
+ * @returns {Promise<void>}
+ */
 export async function diff() {
   const config = await loadConfig()
   const specs = await listFiles(join(config.htDir, 'spec'), ['.json'])
@@ -44,4 +49,3 @@ function renderDiffReport(config, spec) {
 </html>
 `
 }
-
diff --git a/src/stages/doctor.js b/src/stages/doctor.js
index 8905303..46f6695 100644
--- a/src/stages/doctor.js
+++ b/src/stages/doctor.js
@@ -4,6 +4,11 @@ import { commandExists, resolveAgentCommand } from '../lib/agent.js'
 import { exists } from '../lib/files.js'
 import { playwrightCliAvailable, resolvePlaywrightCli } from '../lib/playwright-cli.js'
 
+/**
+ * 檢查本機執行 HTML Transform pipeline 所需的資料夾與命令。
+ *
+ * @returns {Promise<void>}
+ */
 export async function doctor() {
   const config = await loadConfig()
   const agentCommand = resolveAgentCommand(config.agent)[0]
diff --git a/src/stages/plan.js b/src/stages/plan.js
index 43bb84c..1f6a579 100644
--- a/src/stages/plan.js
+++ b/src/stages/plan.js
@@ -4,6 +4,13 @@ import { basename, join } from 'node:path'
 import { loadConfig } from '../lib/config.js'
 import { listFiles, readJson, writeJson } from '../lib/files.js'
 
+/**
+ * 執行 Stage 2：依 LayoutSpec 建立 tasklist、component mapping 與專案/API contract artifacts。
+ *
+ * @param {object} options 執行選項。
+ * @param {boolean} [options.assumeYes] 跳過互動 review 提示。
+ * @returns {Promise<void>}
+ */
 export async function plan(options = {}) {
   const config = await loadConfig()
   const specs = await listFiles(join(config.htDir, 'spec'), ['.json'])
@@ -117,4 +124,3 @@ async function writeMarkdown(path, content) {
 function renderPreview(taskList) {
   return taskList.tasks.map((task) => `${task.id} -> ${task.targetFile}`).join('\n')
 }
-
diff --git a/src/stages/run.js b/src/stages/run.js
index 2fa05a4..858805d 100644
--- a/src/stages/run.js
+++ b/src/stages/run.js
@@ -3,6 +3,13 @@ import { basename, dirname, join } from 'node:path'
 import { loadConfig } from '../lib/config.js'
 import { ensureDir, exists, listFiles, readJson, writeJson } from '../lib/files.js'
 
+/**
+ * 執行 Stage 3：根據 TaskList 產生 output 內的 Vue/Vuetify 檔案與 run metadata。
+ *
+ * @param {object} options 執行選項。
+ * @param {boolean} [options.retryFailed] 僅重跑狀態為 `error` 的 task。
+ * @returns {Promise<void>}
+ */
 export async function runTasks(options = {}) {
   const config = await loadConfig()
   const taskListPath = join(config.htDir, 'plan/tasklist.json')
@@ -94,4 +101,3 @@ function topoSort(tasks) {
 function escapeHtml(value) {
   return String(value).replaceAll('&', '&amp;').replaceAll('<', '&lt;').replaceAll('"', '&quot;')
 }
-
diff --git a/src/stages/scan.js b/src/stages/scan.js
index 4311ec5..7081a4a 100644
--- a/src/stages/scan.js
+++ b/src/stages/scan.js
@@ -10,6 +10,11 @@ const viewports = [
   { name: 'mobile', width: 375, height: 812 }
 ]
 
+/**
+ * 執行 Stage 1：掃描 prototype HTML，產生 deterministic evidence 與 LayoutSpec artifacts。
+ *
+ * @returns {Promise<void>}
+ */
 export async function scan() {
   const config = await loadConfig()
   const htmlFiles = await listFiles(config.prototypeDir, ['.html'])
diff --git a/src/stages/status.js b/src/stages/status.js
index cf5a34a..41655a4 100644
--- a/src/stages/status.js
+++ b/src/stages/status.js
@@ -2,6 +2,11 @@ import { join } from 'node:path'
 import { loadConfig } from '../lib/config.js'
 import { exists, readJson } from '../lib/files.js'
 
+/**
+ * 顯示目前 TaskList 中各 task 狀態的數量。
+ *
+ * @returns {Promise<void>}
+ */
 export async function status() {
   const config = await loadConfig()
   const path = join(config.htDir, 'plan/tasklist.json')
@@ -15,4 +20,3 @@ export async function status() {
     console.log(`${state}: ${counts[state]?.length ?? 0}`)
   }
 }
-
diff --git a/src/stages/verify.js b/src/stages/verify.js
index f8901a0..cec1062 100644
--- a/src/stages/verify.js
+++ b/src/stages/verify.js
@@ -3,6 +3,11 @@ import { join } from 'node:path'
 import { loadConfig } from '../lib/config.js'
 import { exists, listFiles, readJson, writeJson } from '../lib/files.js'
 
+/**
+ * 執行 Stage 5：執行設定中的 quality commands，並寫出 MVP verification report。
+ *
+ * @returns {Promise<void>}
+ */
 export async function verify() {
   const config = await loadConfig()
   const quality = {}
@@ -43,4 +48,3 @@ async function runDomChecks(config) {
   const missing = taskList.tasks.filter((task) => !outputFiles.some((file) => file.endsWith(task.targetFile)))
   return { status: missing.length === 0 ? 'passed' : 'failed', missingTargets: missing.map((task) => task.targetFile) }
 }
-