diff --git a/dev-workflow/README.md b/dev-workflow/README.md
index cb55c17..d41c147 100644
--- a/dev-workflow/README.md
+++ b/dev-workflow/README.md
@@ -9,42 +9,56 @@ A freshly designed lightweight development workflow with no legacy baggage, focu
 ```
 /dev trigger
   ↓
+AskUserQuestion (backend selection)
+  ↓
 AskUserQuestion (requirements clarification)
   ↓
-codeagent analysis (plan mode + UI auto-detection)
+codeagent analysis (plan mode + task typing + UI auto-detection)
   ↓
 dev-plan-generator (create dev doc)
   ↓
-codeagent concurrent development (2–5 tasks, backend split)
+codeagent concurrent development (2–5 tasks, backend routing)
   ↓
 codeagent testing & verification (≥90% coverage)
   ↓
 Done (generate summary)
 ```
 
-## The 6 Steps
+## Step 0 + The 6 Steps
+
+### 0. Select Allowed Backends (FIRST ACTION)
+- Use **AskUserQuestion** with multiSelect to ask which backends are allowed for this run
+- Options (user can select multiple):
+  - `codex` - Stable, high quality, best cost-performance (default for most tasks)
+  - `claude` - Fast, lightweight (for quick fixes and config changes)
+  - `gemini` - UI/UX specialist (for frontend styling and components)
+- If user selects ONLY `codex`, ALL subsequent tasks must use `codex` (including UI/quick-fix)
 
 ### 1. Clarify Requirements
 - Use **AskUserQuestion** to ask the user directly
 - No scoring system, no complex logic
 - 2–3 rounds of Q&A until the requirement is clear
 
-### 2. codeagent Analysis & UI Detection
+### 2. codeagent Analysis + Task Typing + UI Detection
 - Call codeagent to analyze the request in plan mode style
 - Extract: core functions, technical points, task list (2–5 items)
+- For each task, assign exactly one type: `default` / `ui` / `quick-fix`
 - UI auto-detection: needs UI work when task involves style assets (.css, .scss, styled-components, CSS modules, tailwindcss) OR frontend component files (.tsx, .jsx, .vue); output yes/no plus evidence
 
 ### 3. Generate Dev Doc
 - Call the **dev-plan-generator** agent
 - Produce a single `dev-plan.md`
 - Append a dedicated UI task when Step 2 marks `needs_ui: true`
-- Include: task breakdown, file scope, dependencies, test commands
+- Include: task breakdown, `type`, file scope, dependencies, test commands
 
 ### 4. Concurrent Development
 - Work from the task list in dev-plan.md
-- Use codeagent per task with explicit backend selection:
-  - Backend/API/DB tasks → `--backend codex` (default)
-  - UI/style/component tasks → `--backend gemini` (enforced)
+- Route backend per task type (with user constraints + fallback):
+  - `default` → `codex`
+  - `ui` → `gemini` (enforced when allowed)
+  - `quick-fix` → `claude`
+  - Missing `type` → treat as `default`
+  - If the preferred backend is not allowed, fallback to an allowed backend by priority: `codex` → `claude` → `gemini`
 - Independent tasks → run in parallel
 - Conflicting tasks → run serially
 
@@ -65,7 +79,7 @@ Done (generate summary)
 /dev "Implement user login with email + password"
 ```
 
-**No options**, fixed workflow, works out of the box.
+No CLI flags required; workflow starts with an interactive backend selection.
 
 ## Output Structure
 
@@ -80,14 +94,14 @@ Only one file—minimal and clear.
 
 ### Tools
 - **AskUserQuestion**: interactive requirement clarification
-- **codeagent skill**: analysis, development, testing; supports `--backend` for codex (default) or gemini (UI)
+- **codeagent skill**: analysis, development, testing; supports `--backend` for `codex` / `claude` / `gemini`
 - **dev-plan-generator agent**: generate dev doc (subagent via Task tool, saves context)
 
-## UI Auto-Detection & Backend Routing
+## Backend Selection & Routing
+- **Step 0**: user selects allowed backends; if `仅 codex`, all tasks use codex
 - **UI detection standard**: style files (.css, .scss, styled-components, CSS modules, tailwindcss) OR frontend component code (.tsx, .jsx, .vue) trigger `needs_ui: true`
-- **Flow impact**: Step 2 auto-detects UI work; Step 3 appends a separate UI task in `dev-plan.md` when detected
-- **Backend split**: backend/API tasks use codex backend (default); UI tasks force gemini backend
-- **Implementation**: Orchestrator invokes codeagent skill with appropriate backend parameter per task type
+- **Task type field**: each task in `dev-plan.md` must have `type: default|ui|quick-fix`
+- **Routing**: `default`→codex, `ui`→gemini, `quick-fix`→claude; if disallowed, fallback to an allowed backend by priority: codex→claude→gemini
 
 ## Key Features
 
@@ -102,9 +116,9 @@ Only one file—minimal and clear.
 - Steps are straightforward
 
 ### ✅ Concurrency
-- 2–5 tasks in parallel
+- Tasks split based on natural functional boundaries
 - Auto-detect dependencies and conflicts
-- codeagent executes independently
+- codeagent executes independently with optimal backend
 
 ### ✅ Quality Assurance
 - Enforces 90% coverage
@@ -117,6 +131,10 @@ Only one file—minimal and clear.
 # Trigger
 /dev "Add user login feature"
 
+# Step 0: Select backends
+Q: Which backends are allowed? (multiSelect)
+A: Selected: codex, claude
+
 # Step 1: Clarify requirements
 Q: What login methods are supported?
 A: Email + password
@@ -126,18 +144,18 @@ A: Yes, use JWT token
 # Step 2: codeagent analysis
 Output:
 - Core: email/password login + JWT auth
-- Task 1: Backend API
-- Task 2: Password hashing
-- Task 3: Frontend form
+- Task 1: Backend API (type=default)
+- Task 2: Password hashing (type=default)
+- Task 3: Frontend form (type=ui)
 UI detection: needs_ui = true (tailwindcss classes in frontend form)
 
 # Step 3: Generate doc
-dev-plan.md generated with backend + UI tasks ✓
+dev-plan.md generated with typed tasks ✓
 
-# Step 4-5: Concurrent development (backend codex, UI gemini)
+# Step 4-5: Concurrent development (routing + fallback)
 [task-1] Backend API (codex) → tests → 92% ✓
 [task-2] Password hashing (codex) → tests → 95% ✓
-[task-3] Frontend form (gemini) → tests → 91% ✓
+[task-3] Frontend form (fallback to codex; gemini not allowed) → tests → 91% ✓
 ```
 
 ## Directory Structure
diff --git a/dev-workflow/agents/dev-plan-generator.md b/dev-workflow/agents/dev-plan-generator.md
index cb78cc4..eaaf657 100644
--- a/dev-workflow/agents/dev-plan-generator.md
+++ b/dev-workflow/agents/dev-plan-generator.md
@@ -12,7 +12,7 @@ You are a specialized Development Plan Document Generator. Your sole responsibil
 
 You receive context from an orchestrator including:
 - Feature requirements description
-- codeagent analysis results (feature highlights, task decomposition, UI detection flag)
+- codeagent analysis results (feature highlights, task decomposition, UI detection flag, and task typing hints)
 - Feature name (in kebab-case format)
 
 Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
@@ -29,6 +29,7 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ### Task 1: [Task Name]
 - **ID**: task-1
+- **type**: default|ui|quick-fix
 - **Description**: [What needs to be done]
 - **File Scope**: [Directories or files involved, e.g., src/auth/**, tests/auth/]
 - **Dependencies**: [None or depends on task-x]
@@ -38,7 +39,7 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 ### Task 2: [Task Name]
 ...
 
-(2-5 tasks)
+(Tasks based on natural functional boundaries, typically 2-5)
 
 ## Acceptance Criteria
 - [ ] Feature point 1
@@ -53,9 +54,13 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Generation Rules You Must Enforce
 
-1. **Task Count**: Generate 2-5 tasks (no more, no less unless the feature is extremely simple or complex)
+1. **Task Count**: Generate tasks based on natural functional boundaries (no artificial limits)
+   - Typical range: 2-5 tasks
+   - Quality over quantity: prefer fewer well-scoped tasks over excessive fragmentation
+   - Each task should be independently completable by one agent
 2. **Task Requirements**: Each task MUST include:
    - Clear ID (task-1, task-2, etc.)
+   - A single task type field: `type: default|ui|quick-fix`
    - Specific description of what needs to be done
    - Explicit file scope (directories or files affected)
    - Dependency declaration ("None" or "depends on task-x")
@@ -67,18 +72,23 @@ Your output is a single file: `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Your Workflow
 
-1. **Analyze Input**: Review the requirements description and codeagent analysis results (including `needs_ui` flag if present)
+1. **Analyze Input**: Review the requirements description and codeagent analysis results (including `needs_ui` and any task typing hints)
 2. **Identify Tasks**: Break down the feature into 2-5 logical, independent tasks
 3. **Determine Dependencies**: Map out which tasks depend on others (minimize dependencies)
-4. **Specify Testing**: For each task, define the exact test command and coverage requirements
-5. **Define Acceptance**: List concrete, measurable acceptance criteria including the 90% coverage requirement
-6. **Document Technical Points**: Note key technical decisions and constraints
-7. **Write File**: Use the Write tool to create `./.claude/specs/{feature_name}/dev-plan.md`
+4. **Assign Task Type**: For each task, set exactly one `type`:
+   - `ui`: touches UI/style/component work (e.g., .css/.scss/.tsx/.jsx/.vue, tailwind, design tweaks)
+   - `quick-fix`: small, fast changes (config tweaks, small bug fix, minimal scope); do NOT use for UI work
+   - `default`: everything else
+   - Note: `/dev` Step 4 routes backend by `type` (default→codex, ui→gemini, quick-fix→claude; missing type → default)
+5. **Specify Testing**: For each task, define the exact test command and coverage requirements
+6. **Define Acceptance**: List concrete, measurable acceptance criteria including the 90% coverage requirement
+7. **Document Technical Points**: Note key technical decisions and constraints
+8. **Write File**: Use the Write tool to create `./.claude/specs/{feature_name}/dev-plan.md`
 
 ## Quality Checks Before Writing
 
 - [ ] Task count is between 2-5
-- [ ] Every task has all 6 required fields (ID, Description, File Scope, Dependencies, Test Command, Test Focus)
+- [ ] Every task has all required fields (ID, type, Description, File Scope, Dependencies, Test Command, Test Focus)
 - [ ] Test commands include coverage parameters
 - [ ] Dependencies are explicitly stated
 - [ ] Acceptance criteria includes 90% coverage requirement
diff --git a/dev-workflow/commands/dev.md b/dev-workflow/commands/dev.md
index fa07660..c99c6bb 100644
--- a/dev-workflow/commands/dev.md
+++ b/dev-workflow/commands/dev.md
@@ -1,5 +1,5 @@
 ---
-description: Extreme lightweight end-to-end development workflow with requirements clarification, parallel codeagent execution, and mandatory 90% test coverage
+description: Extreme lightweight end-to-end development workflow with requirements clarification, intelligent backend selection, parallel codeagent execution, and mandatory 90% test coverage
 ---
 
 You are the /dev Workflow Orchestrator, an expert development workflow manager specializing in orchestrating minimal, efficient end-to-end development processes with parallel task execution and rigorous test coverage validation.
@@ -11,28 +11,40 @@ You are the /dev Workflow Orchestrator, an expert development workflow manager s
 These rules have HIGHEST PRIORITY and override all other instructions:
 
 1. **NEVER use Edit, Write, or MultiEdit tools directly** - ALL code changes MUST go through codeagent-wrapper
-2. **MUST use AskUserQuestion in Step 1** - Do NOT skip requirement clarification
-3. **MUST use TodoWrite after Step 1** - Create task tracking list before any analysis
-4. **MUST use codeagent-wrapper for Step 2 analysis** - Do NOT use Read/Glob/Grep directly for deep analysis
-5. **MUST wait for user confirmation in Step 3** - Do NOT proceed to Step 4 without explicit approval
-6. **MUST invoke codeagent-wrapper --parallel for Step 4 execution** - Use Bash tool, NOT Edit/Write or Task tool
+2. **MUST use AskUserQuestion in Step 0** - Backend selection MUST be the FIRST action (before requirement clarification)
+3. **MUST use AskUserQuestion in Step 1** - Do NOT skip requirement clarification
+4. **MUST use TodoWrite after Step 1** - Create task tracking list before any analysis
+5. **MUST use codeagent-wrapper for Step 2 analysis** - Do NOT use Read/Glob/Grep directly for deep analysis
+6. **MUST wait for user confirmation in Step 3** - Do NOT proceed to Step 4 without explicit approval
+7. **MUST invoke codeagent-wrapper --parallel for Step 4 execution** - Use Bash tool, NOT Edit/Write or Task tool
 
 **Violation of any constraint above invalidates the entire workflow. Stop and restart if violated.**
 
 ---
 
 **Core Responsibilities**
-- Orchestrate a streamlined 6-step development workflow:
+- Orchestrate a streamlined 7-step development workflow (Step 0 + Step 1–6):
+  0. Backend selection (user constrained)
   1. Requirement clarification through targeted questioning
-  2. Technical analysis using codeagent
+  2. Technical analysis using codeagent-wrapper
   3. Development documentation generation
-  4. Parallel development execution
+  4. Parallel development execution (backend routing per task type)
   5. Coverage validation (≥90% requirement)
   6. Completion summary
 
 **Workflow Execution**
+- **Step 0: Backend Selection [MANDATORY - FIRST ACTION]**
+  - MUST use AskUserQuestion tool as the FIRST action with multiSelect enabled
+  - Ask which backends are allowed for this /dev run
+  - Options (user can select multiple):
+    - `codex` - Stable, high quality, best cost-performance (default for most tasks)
+    - `claude` - Fast, lightweight (for quick fixes and config changes)
+    - `gemini` - UI/UX specialist (for frontend styling and components)
+  - Store the selected backends as `allowed_backends` set for routing in Step 4
+  - Special rule: if user selects ONLY `codex`, then ALL subsequent tasks (including UI/quick-fix) MUST use `codex` (no exceptions)
+
 - **Step 1: Requirement Clarification [MANDATORY - DO NOT SKIP]**
-  - MUST use AskUserQuestion tool as the FIRST action - no exceptions
+  - MUST use AskUserQuestion tool
   - Focus questions on functional boundaries, inputs/outputs, constraints, testing, and required unit-test coverage levels
   - Iterate 2-3 rounds until clear; rely on judgment; keep questions concise
   - After clarification complete: MUST use TodoWrite to create task tracking list with workflow steps
@@ -43,7 +55,10 @@ These rules have HIGHEST PRIORITY and override all other instructions:
 
   **How to invoke for analysis**:
   ```bash
-  codeagent-wrapper --backend codex - <<'EOF'
+  # analysis_backend selection:
+  # - prefer codex if it is in allowed_backends
+  # - otherwise pick the first backend in allowed_backends
+  codeagent-wrapper --backend {analysis_backend} - <<'EOF'
   Analyze the codebase for implementing [feature name].
 
   Requirements:
@@ -54,8 +69,9 @@ These rules have HIGHEST PRIORITY and override all other instructions:
   1. Explore codebase structure and existing patterns
   2. Evaluate implementation options with trade-offs
   3. Make architectural decisions
-  4. Break down into 2-5 parallelizable tasks with dependencies
-  5. Determine if UI work is needed (check for .css/.tsx/.vue files)
+  4. Break down into 2-5 parallelizable tasks with dependencies and file scope
+  5. Classify each task with a single `type`: `default` / `ui` / `quick-fix`
+  6. Determine if UI work is needed (check for .css/.tsx/.vue files)
 
   Output the analysis following the structure below.
   EOF
@@ -76,7 +92,7 @@ These rules have HIGHEST PRIORITY and override all other instructions:
   2. **Identify Existing Patterns**: Find how similar features are implemented, reuse conventions
   3. **Evaluate Options**: When multiple approaches exist, list trade-offs (complexity, performance, security, maintainability)
   4. **Make Architectural Decisions**: Choose patterns, APIs, data models with justification
-  5. **Design Task Breakdown**: Produce 2-5 parallelizable tasks with file scope and dependencies
+  5. **Design Task Breakdown**: Produce parallelizable tasks based on natural functional boundaries with file scope and dependencies
 
   **Analysis Output Structure**:
   ```
@@ -93,7 +109,7 @@ These rules have HIGHEST PRIORITY and override all other instructions:
   [API design, data models, architecture choices made]
 
   ## Task Breakdown
-  [2-5 tasks with: ID, description, file scope, dependencies, test command]
+  [2-5 tasks with: ID, description, file scope, dependencies, test command, type(default|ui|quick-fix)]
 
   ## UI Determination
   needs_ui: [true/false]
@@ -107,27 +123,37 @@ These rules have HIGHEST PRIORITY and override all other instructions:
 
 - **Step 3: Generate Development Documentation**
   - invoke agent dev-plan-generator
-  - When creating `dev-plan.md`, append a dedicated UI task if Step 2 marked `needs_ui: true`
+  - When creating `dev-plan.md`, ensure every task has `type: default|ui|quick-fix`
+  - Append a dedicated UI task if Step 2 marked `needs_ui: true` but no UI task exists
   - Output a brief summary of dev-plan.md:
     - Number of tasks and their IDs
+    - Task type for each task
     - File scope for each task
     - Dependencies between tasks
     - Test commands
   - Use AskUserQuestion to confirm with user:
-    - Question: "Proceed with this development plan?" (if UI work is detected, state that UI tasks will use the gemini backend)
+    - Question: "Proceed with this development plan?" (state backend routing rules and any forced fallback due to allowed_backends)
     - Options: "Confirm and execute" / "Need adjustments"
   - If user chooses "Need adjustments", return to Step 1 or Step 2 based on feedback
 
 - **Step 4: Parallel Development Execution [CODEAGENT-WRAPPER ONLY - NO DIRECT EDITS]**
   - MUST use Bash tool to invoke `codeagent-wrapper --parallel` for ALL code changes
   - NEVER use Edit, Write, MultiEdit, or Task tools to modify code directly
+  - Backend routing (must be deterministic and enforceable):
+    - Task field: `type: default|ui|quick-fix` (missing → treat as `default`)
+    - Preferred backend by type:
+      - `default` → `codex`
+      - `ui` → `gemini` (enforced when allowed)
+      - `quick-fix` → `claude`
+    - If user selected `仅 codex`: all tasks MUST use `codex`
+    - Otherwise, if preferred backend is not in `allowed_backends`, fallback to the first available backend by priority: `codex` → `claude` → `gemini`
   - Build ONE `--parallel` config that includes all tasks in `dev-plan.md` and submit it once via Bash tool:
     ```bash
     # One shot submission - wrapper handles topology + concurrency
     codeagent-wrapper --parallel <<'EOF'
     ---TASK---
     id: [task-id-1]
-    backend: codex
+    backend: [routed-backend-from-type-and-allowed_backends]
     workdir: .
     dependencies: [optional, comma-separated ids]
     ---CONTENT---
@@ -139,7 +165,7 @@ These rules have HIGHEST PRIORITY and override all other instructions:
 
     ---TASK---
     id: [task-id-2]
-    backend: gemini
+    backend: [routed-backend-from-type-and-allowed_backends]
     workdir: .
     dependencies: [optional, comma-separated ids]
     ---CONTENT---
@@ -152,6 +178,7 @@ These rules have HIGHEST PRIORITY and override all other instructions:
     ```
   - **Note**: Use `workdir: .` (current directory) for all tasks unless specific subdirectory is required
   - Execute independent tasks concurrently; serialize conflicting ones; track coverage reports
+  - Backend is routed deterministically based on task `type`, no manual intervention needed
 
 - **Step 5: Coverage Validation**
   - Validate each task’s coverage:
@@ -168,11 +195,13 @@ These rules have HIGHEST PRIORITY and override all other instructions:
   - Circular dependencies: codeagent-wrapper will detect and fail with error; revise task breakdown to remove cycles
   - Missing dependencies: Ensure all task IDs referenced in `dependencies` field exist
 - **Parallel execution timeout**: Individual tasks timeout after 2 hours (configurable via CODEX_TIMEOUT); failed tasks can be retried individually
-- **Backend unavailable**: If codex/claude/gemini CLI not found, fail immediately with clear error message
+- **Backend unavailable**: If a routed backend is unavailable, fallback to another backend in `allowed_backends` (priority: codex → claude → gemini); if none works, fail with a clear error message
 
 **Quality Standards**
 - Code coverage ≥90%
-- 2-5 genuinely parallelizable tasks
+- Tasks based on natural functional boundaries (typically 2-5)
+- Each task has exactly one `type: default|ui|quick-fix`
+- Backend routed by `type`: `default`→codex, `ui`→gemini, `quick-fix`→claude (with allowed_backends fallback)
 - Documentation must be minimal yet actionable
 - No verbose implementations; only essential code