feat: Add YOLO mode for rapid prototyping without browser testing

Add a new YOLO (You Only Live Once) mode that skips all browser testing
and regression tests for faster feature iteration during prototyping.

Changes made:

**Core YOLO Mode Implementation:**
- Add --yolo CLI flag to autonomous_agent_demo.py
- Update agent.py to accept yolo_mode parameter and select appropriate prompt
- Modify client.py to conditionally include Playwright MCP server (excluded in YOLO mode)
- Add coding_prompt_yolo.template.md with static analysis only verification
- Add get_coding_prompt_yolo() to prompts.py

**Server/API Updates:**
- Add AgentStartRequest schema with yolo_mode field
- Update AgentStatus to include yolo_mode
- Modify process_manager.py to pass --yolo flag to subprocess
- Update agent router to accept yolo_mode in start request

**UI Updates:**
- Add YOLO toggle button (lightning bolt icon) in AgentControl
- Show YOLO mode indicator when agent is running in YOLO mode
- Add useAgentStatus hook to track current mode
- Update startAgent API to accept yoloMode parameter
- Add YOLO toggle in SpecCreationChat completion flow

**Spec Creation Improvements:**
- Fix create-spec.md to properly replace [FEATURE_COUNT] placeholder
- Add REQUIRED FEATURE COUNT section to initializer_prompt.template.md
- Fix spec_chat_session.py to create security settings file for Claude SDK
- Delete app_spec.txt before spec creation to allow fresh creation

**Documentation:**
- Add YOLO mode section to CLAUDE.md with usage examples
- Add checkpoint.md slash command for creating detailed commits

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/commands/checkpoint.md

@@ -0,0 +1,40 @@
+---
+description: Create commit with detailed comment
+---
+
+Please create a comprehensive checkpoint commit with the following steps:
+
+1. **Initialize Git if needed**: Run `git init` if git has not been instantiated for the project yet.
+
+2. **Analyze all changes**:
+
+   - Run `git status` to see all tracked and untracked files
+   - Run `git diff` to see detailed changes in tracked files
+   - Run `git log -5 --oneline` to understand the commit message style of this repository
+
+3. **Stage everything**:
+
+   - Add ALL tracked changes (modified and deleted files)
+   - Add ALL untracked files (new files)
+   - Use `git add -A` or `git add .` to stage everything
+
+4. **Create a detailed commit message**:
+
+   - **First line**: Write a clear, concise summary (50-72 chars) describing the primary change
+     - Use imperative mood (e.g., "Add feature" not "Added feature")
+     - Examples: "feat: add user authentication", "fix: resolve database connection issue", "refactor: improve API route structure"
+   - **Body**: Provide a detailed description including:
+     - What changes were made (list of key modifications)
+     - Why these changes were made (purpose/motivation)
+     - Any important technical details or decisions
+     - Breaking changes or migration notes if applicable
+   - **Footer**: Include co-author attribution as shown in the Git Safety Protocol
+
+5. **Execute the commit**: Create the commit with the properly formatted message following this repository's conventions.
+
+IMPORTANT:
+
+- Do NOT skip any files - include everything
+- Make the commit message descriptive enough that someone reviewing the git log can understand what was accomplished
+- Follow the project's existing commit message conventions (check git log first)
+- Include the Claude Code co-author attribution in the commit message

.claude/commands/create-spec.md

@@ -459,10 +459,19 @@ Create a new file using this XML structure:
 If the output directory has an existing `initializer_prompt.md`, read it and update the feature count.
 If not, copy from `.claude/templates/initializer_prompt.template.md` first, then update.
 
-Update the feature count references to match the derived count from Phase 4L:
+**CRITICAL: You MUST update the feature count placeholder:**
 
-- Line containing "create ... test cases" - update to the derived feature count
-- Line containing "Minimum ... features" - update to the derived feature count
+1. Find the line containing `**[FEATURE_COUNT]**` in the "REQUIRED FEATURE COUNT" section
+2. Replace `[FEATURE_COUNT]` with the exact number agreed upon in Phase 4L (e.g., `25`)
+3. The result should read like: `You must create exactly **25** features using the...`
+
+**Example edit:**
+```
+Before: **CRITICAL:** You must create exactly **[FEATURE_COUNT]** features using the `feature_create_bulk` tool.
+After:  **CRITICAL:** You must create exactly **25** features using the `feature_create_bulk` tool.
+```
+
+**Verify the update:** After editing, read the file again to confirm the feature count appears correctly. If `[FEATURE_COUNT]` still appears in the file, the update failed and you must try again.
 
 **Note:** You do NOT need to update `coding_prompt.md` - the coding agent works through features one at a time regardless of total count.
 

.claude/templates/coding_prompt_yolo.template.md

@@ -0,0 +1,274 @@
+<!-- YOLO MODE PROMPT - Keep synchronized with coding_prompt.template.md -->
+<!-- Last synced: 2026-01-01 -->
+
+## YOLO MODE - Rapid Prototyping (Testing Disabled)
+
+**WARNING:** This mode skips all browser testing and regression tests.
+Features are marked as passing after lint/type-check succeeds.
+Use for rapid prototyping only - not for production-quality development.
+
+---
+
+## YOUR ROLE - CODING AGENT (YOLO MODE)
+
+You are continuing work on a long-running autonomous development task.
+This is a FRESH context window - you have no memory of previous sessions.
+
+### STEP 1: GET YOUR BEARINGS (MANDATORY)
+
+Start by orienting yourself:
+
+```bash
+# 1. See your working directory
+pwd
+
+# 2. List files to understand project structure
+ls -la
+
+# 3. Read the project specification to understand what you're building
+cat app_spec.txt
+
+# 4. Read progress notes from previous sessions
+cat claude-progress.txt
+
+# 5. Check recent git history
+git log --oneline -20
+```
+
+Then use MCP tools to check feature status:
+
+```
+# 6. Get progress statistics (passing/total counts)
+Use the feature_get_stats tool
+
+# 7. Get the next feature to work on
+Use the feature_get_next tool
+```
+
+Understanding the `app_spec.txt` is critical - it contains the full requirements
+for the application you're building.
+
+### STEP 2: START SERVERS (IF NOT RUNNING)
+
+If `init.sh` exists, run it:
+
+```bash
+chmod +x init.sh
+./init.sh
+```
+
+Otherwise, start servers manually and document the process.
+
+### STEP 3: CHOOSE ONE FEATURE TO IMPLEMENT
+
+Get the next feature to implement:
+
+```
+# Get the highest-priority pending feature
+Use the feature_get_next tool
+```
+
+Once you've retrieved the feature, **immediately mark it as in-progress**:
+
+```
+# Mark feature as in-progress to prevent other sessions from working on it
+Use the feature_mark_in_progress tool with feature_id=42
+```
+
+Focus on completing one feature in this session before moving on to other features.
+It's ok if you only complete one feature in this session, as there will be more sessions later that continue to make progress.
+
+#### When to Skip a Feature (EXTREMELY RARE)
+
+**Skipping should almost NEVER happen.** Only skip for truly external blockers you cannot control:
+
+- **External API not configured**: Third-party service credentials missing (e.g., Stripe keys, OAuth secrets)
+- **External service unavailable**: Dependency on service that's down or inaccessible
+- **Environment limitation**: Hardware or system requirement you cannot fulfill
+
+**NEVER skip because:**
+
+| Situation | Wrong Action | Correct Action |
+|-----------|--------------|----------------|
+| "Page doesn't exist" | Skip | Create the page |
+| "API endpoint missing" | Skip | Implement the endpoint |
+| "Database table not ready" | Skip | Create the migration |
+| "Component not built" | Skip | Build the component |
+| "No data to test with" | Skip | Create test data or build data entry flow |
+| "Feature X needs to be done first" | Skip | Build feature X as part of this feature |
+
+If a feature requires building other functionality first, **build that functionality**. You are the coding agent - your job is to make the feature work, not to defer it.
+
+If you must skip (truly external blocker only):
+
+```
+Use the feature_skip tool with feature_id={id}
+```
+
+Document the SPECIFIC external blocker in `claude-progress.txt`. "Functionality not built" is NEVER a valid reason.
+
+### STEP 4: IMPLEMENT THE FEATURE
+
+Implement the chosen feature thoroughly:
+
+1. Write the code (frontend and/or backend as needed)
+2. Ensure proper error handling
+3. Follow existing code patterns in the codebase
+
+### STEP 5: VERIFY WITH LINT AND TYPE CHECK (YOLO MODE)
+
+**In YOLO mode, verification is done through static analysis only.**
+
+Run the appropriate lint and type-check commands for your project:
+
+**For TypeScript/JavaScript projects:**
+```bash
+npm run lint
+npm run typecheck  # or: npx tsc --noEmit
+```
+
+**For Python projects:**
+```bash
+ruff check .
+mypy .
+```
+
+**If lint/type-check passes:** Proceed to mark the feature as passing.
+
+**If lint/type-check fails:** Fix the errors before proceeding.
+
+### STEP 6: UPDATE FEATURE STATUS
+
+**YOU CAN ONLY MODIFY ONE FIELD: "passes"**
+
+After lint/type-check passes, mark the feature as passing:
+
+```
+# Mark feature #42 as passing (replace 42 with the actual feature ID)
+Use the feature_mark_passing tool with feature_id=42
+```
+
+**NEVER:**
+
+- Delete features
+- Edit feature descriptions
+- Modify feature steps
+- Combine or consolidate features
+- Reorder features
+
+### STEP 7: COMMIT YOUR PROGRESS
+
+Make a descriptive git commit:
+
+```bash
+git add .
+git commit -m "Implement [feature name] - YOLO mode
+
+- Added [specific changes]
+- Lint/type-check passing
+- Marked feature #X as passing
+"
+```
+
+### STEP 8: UPDATE PROGRESS NOTES
+
+Update `claude-progress.txt` with:
+
+- What you accomplished this session
+- Which feature(s) you completed
+- Any issues discovered or fixed
+- What should be worked on next
+- Current completion status (e.g., "45/200 features passing")
+
+### STEP 9: END SESSION CLEANLY
+
+Before context fills up:
+
+1. Commit all working code
+2. Update claude-progress.txt
+3. Mark features as passing if lint/type-check verified
+4. Ensure no uncommitted changes
+5. Leave app in working state
+
+---
+
+## FEATURE TOOL USAGE RULES (CRITICAL - DO NOT VIOLATE)
+
+The feature tools exist to reduce token usage. **DO NOT make exploratory queries.**
+
+### ALLOWED Feature Tools (ONLY these):
+
+```
+# 1. Get progress stats (passing/in_progress/total counts)
+feature_get_stats
+
+# 2. Get the NEXT feature to work on (one feature only)
+feature_get_next
+
+# 3. Mark a feature as in-progress (call immediately after feature_get_next)
+feature_mark_in_progress with feature_id={id}
+
+# 4. Mark a feature as passing (after lint/type-check succeeds)
+feature_mark_passing with feature_id={id}
+
+# 5. Skip a feature (moves to end of queue) - ONLY when blocked by dependency
+feature_skip with feature_id={id}
+
+# 6. Clear in-progress status (when abandoning a feature)
+feature_clear_in_progress with feature_id={id}
+```
+
+### RULES:
+
+- Do NOT try to fetch lists of all features
+- Do NOT query features by category
+- Do NOT list all pending features
+
+**You do NOT need to see all features.** The feature_get_next tool tells you exactly what to work on. Trust it.
+
+---
+
+## EMAIL INTEGRATION (DEVELOPMENT MODE)
+
+When building applications that require email functionality (password resets, email verification, notifications, etc.), you typically won't have access to a real email service or the ability to read email inboxes.
+
+**Solution:** Configure the application to log emails to the terminal instead of sending them.
+
+- Password reset links should be printed to the console
+- Email verification links should be printed to the console
+- Any notification content should be logged to the terminal
+
+**During testing:**
+
+1. Trigger the email action (e.g., click "Forgot Password")
+2. Check the terminal/server logs for the generated link
+3. Use that link directly to verify the functionality works
+
+This allows you to fully test email-dependent flows without needing external email services.
+
+---
+
+## IMPORTANT REMINDERS (YOLO MODE)
+
+**Your Goal:** Rapidly prototype the application with all features implemented
+
+**This Session's Goal:** Complete at least one feature
+
+**Quality Bar (YOLO Mode):**
+
+- Code compiles without errors (lint/type-check passing)
+- Follows existing code patterns
+- Basic error handling in place
+- Features are implemented according to spec
+
+**Note:** Browser testing and regression testing are SKIPPED in YOLO mode.
+Features may have bugs that would be caught by manual testing.
+Use standard mode for production-quality verification.
+
+**You have unlimited time.** Take as long as needed to implement features correctly.
+The most important thing is that you leave the code base in a clean state before
+terminating the session (Step 9).
+
+---
+
+Begin by running Step 1 (Get Your Bearings).

.claude/templates/initializer_prompt.template.md

@@ -9,6 +9,16 @@ Start by reading `app_spec.txt` in your working directory. This file contains
 the complete specification for what you need to build. Read it carefully
 before proceeding.
 
+---
+
+## REQUIRED FEATURE COUNT
+
+**CRITICAL:** You must create exactly **[FEATURE_COUNT]** features using the `feature_create_bulk` tool.
+
+This number was determined during spec creation and must be followed precisely. Do not create more or fewer features than specified.
+
+---
+
 ### CRITICAL FIRST TASK: Create Features
 
 Based on `app_spec.txt`, create features using the feature_create_bulk tool. The features are stored in a SQLite database,

CLAUDE.md

@@ -42,8 +42,35 @@ python start.py
 # Run agent directly for a project (use absolute path or registered name)
 python autonomous_agent_demo.py --project-dir C:/Projects/my-app
 python autonomous_agent_demo.py --project-dir my-app  # if registered
+
+# YOLO mode: rapid prototyping without browser testing
+python autonomous_agent_demo.py --project-dir my-app --yolo
 ```
 
+### YOLO Mode (Rapid Prototyping)
+
+YOLO mode skips all testing for faster feature iteration:
+
+```bash
+# CLI
+python autonomous_agent_demo.py --project-dir my-app --yolo
+
+# UI: Toggle the lightning bolt button before starting the agent
+```
+
+**What's different in YOLO mode:**
+- No regression testing (skips `feature_get_for_regression`)
+- No Playwright MCP server (browser automation disabled)
+- Features marked passing after lint/type-check succeeds
+- Faster iteration for prototyping
+
+**What's the same:**
+- Lint and type-check still run to verify code compiles
+- Feature MCP server for tracking progress
+- All other development tools available
+
+**When to use:** Early prototyping when you want to quickly scaffold features without verification overhead. Switch back to standard mode for production-quality development.
+
 ### React UI (in ui/ directory)
 
 ```bash

agent.py

@@ -24,6 +24,7 @@ from progress import print_session_header, print_progress_summary, has_features
 from prompts import (
     get_initializer_prompt,
     get_coding_prompt,
+    get_coding_prompt_yolo,
     copy_spec_to_project,
     has_project_prompts,
 )
@@ -111,6 +112,7 @@ async def run_autonomous_agent(
     project_dir: Path,
     model: str,
     max_iterations: Optional[int] = None,
+    yolo_mode: bool = False,
 ) -> None:
     """
     Run the autonomous agent loop.
@@ -119,12 +121,17 @@ async def run_autonomous_agent(
         project_dir: Directory for the project
         model: Claude model to use
         max_iterations: Maximum number of iterations (None for unlimited)
+        yolo_mode: If True, skip browser testing and use YOLO prompt
     """
     print("\n" + "=" * 70)
     print("  AUTONOMOUS CODING AGENT DEMO")
     print("=" * 70)
     print(f"\nProject directory: {project_dir}")
     print(f"Model: {model}")
+    if yolo_mode:
+        print("Mode: YOLO (testing disabled)")
+    else:
+        print("Mode: Standard (full testing)")
     if max_iterations:
         print(f"Max iterations: {max_iterations}")
     else:
@@ -170,13 +177,17 @@ async def run_autonomous_agent(
         print_session_header(iteration, is_first_run)
 
         # Create client (fresh context)
-        client = create_client(project_dir, model)
+        client = create_client(project_dir, model, yolo_mode=yolo_mode)
 
         # Choose prompt based on session type
         # Pass project_dir to enable project-specific prompts
         if is_first_run:
             prompt = get_initializer_prompt(project_dir)
             is_first_run = False  # Only use initializer once
+        else:
+            # Use YOLO prompt if in YOLO mode
+            if yolo_mode:
+                prompt = get_coding_prompt_yolo(project_dir)
             else:
                 prompt = get_coding_prompt(project_dir)
 

autonomous_agent_demo.py

@@ -16,6 +16,9 @@ Example Usage:
 
     # Limit iterations for testing
     python autonomous_agent_demo.py --project-dir my-app --max-iterations 5
+
+    # YOLO mode: rapid prototyping without browser testing
+    python autonomous_agent_demo.py --project-dir my-app --yolo
 """
 
 import argparse
@@ -57,6 +60,9 @@ Examples:
   # Limit iterations for testing
   python autonomous_agent_demo.py --project-dir my-app --max-iterations 5
 
+  # YOLO mode: rapid prototyping without browser testing
+  python autonomous_agent_demo.py --project-dir my-app --yolo
+
 Authentication:
   Uses Claude CLI credentials from ~/.claude/.credentials.json
   Run 'claude login' to authenticate (handled by start.bat/start.sh)
@@ -84,6 +90,13 @@ Authentication:
         help=f"Claude model to use (default: {DEFAULT_MODEL})",
     )
 
+    parser.add_argument(
+        "--yolo",
+        action="store_true",
+        default=False,
+        help="Enable YOLO mode: rapid prototyping without browser testing",
+    )
+
     return parser.parse_args()
 
 
@@ -122,6 +135,7 @@ def main() -> None:
                 project_dir=project_dir,
                 model=args.model,
                 max_iterations=args.max_iterations,
+                yolo_mode=args.yolo,
             )
         )
     except KeyboardInterrupt:

client.py

@@ -72,13 +72,14 @@ BUILTIN_TOOLS = [
 ]
 
 
-def create_client(project_dir: Path, model: str):
+def create_client(project_dir: Path, model: str, yolo_mode: bool = False):
     """
     Create a Claude Agent SDK client with multi-layered security.
 
     Args:
         project_dir: Directory for the project
         model: Claude model to use
+        yolo_mode: If True, skip Playwright MCP server for rapid prototyping
 
     Returns:
         Configured ClaudeSDKClient (from claude_agent_sdk)
@@ -92,14 +93,14 @@ def create_client(project_dir: Path, model: str):
     Note: Authentication is handled by start.bat/start.sh before this runs.
     The Claude SDK auto-detects credentials from ~/.claude/.credentials.json
     """
-    # Create comprehensive security settings
-    # Note: Using relative paths ("./**") restricts access to project directory
-    # since cwd is set to project_dir
-    security_settings = {
-        "sandbox": {"enabled": True, "autoAllowBashIfSandboxed": True},
-        "permissions": {
-            "defaultMode": "acceptEdits",  # Auto-approve edits within allowed directories
-            "allow": [
+    # Build allowed tools list based on mode
+    # In YOLO mode, exclude Playwright tools for faster prototyping
+    allowed_tools = [*BUILTIN_TOOLS, *FEATURE_MCP_TOOLS]
+    if not yolo_mode:
+        allowed_tools.extend(PLAYWRIGHT_TOOLS)
+
+    # Build permissions list
+    permissions_list = [
         # Allow all file operations within the project directory
         "Read(./**)",
         "Write(./**)",
@@ -109,11 +110,21 @@ def create_client(project_dir: Path, model: str):
         # Bash permission granted here, but actual commands are validated
         # by the bash_security_hook (see security.py for allowed commands)
         "Bash(*)",
-                # Allow Playwright MCP tools for browser automation
-                *PLAYWRIGHT_TOOLS,
         # Allow Feature MCP tools for feature management
         *FEATURE_MCP_TOOLS,
-            ],
+    ]
+    if not yolo_mode:
+        # Allow Playwright MCP tools for browser automation (standard mode only)
+        permissions_list.extend(PLAYWRIGHT_TOOLS)
+
+    # Create comprehensive security settings
+    # Note: Using relative paths ("./**") restricts access to project directory
+    # since cwd is set to project_dir
+    security_settings = {
+        "sandbox": {"enabled": True, "autoAllowBashIfSandboxed": True},
+        "permissions": {
+            "defaultMode": "acceptEdits",  # Auto-approve edits within allowed directories
+            "allow": permissions_list,
         },
     }
 
@@ -129,6 +140,9 @@ def create_client(project_dir: Path, model: str):
     print("   - Sandbox enabled (OS-level bash isolation)")
     print(f"   - Filesystem restricted to: {project_dir.resolve()}")
     print("   - Bash commands restricted to allowlist (see security.py)")
+    if yolo_mode:
+        print("   - MCP servers: features (database) - YOLO MODE (no Playwright)")
+    else:
         print("   - MCP servers: playwright (browser), features (database)")
     print("   - Project settings enabled (skills, commands, CLAUDE.md)")
     print()
@@ -140,20 +154,8 @@ def create_client(project_dir: Path, model: str):
     else:
         print("   - Warning: System Claude CLI not found, using bundled CLI")
 
-    return ClaudeSDKClient(
-        options=ClaudeAgentOptions(
-            model=model,
-            cli_path=system_cli,  # Use system CLI to avoid bundled Bun crash (exit code 3)
-            system_prompt="You are an expert full-stack developer building a production-quality web application.",
-            setting_sources=["project"],  # Enable skills, commands, and CLAUDE.md from project dir
-            max_buffer_size=10 * 1024 * 1024,  # 10MB for large Playwright screenshots
-            allowed_tools=[
-                *BUILTIN_TOOLS,
-                *PLAYWRIGHT_TOOLS,
-                *FEATURE_MCP_TOOLS,
-            ],
+    # Build MCP servers config - features is always included, playwright only in standard mode
     mcp_servers = {
-                "playwright": {"command": "npx", "args": ["@playwright/mcp@latest", "--viewport-size", "1280x720"]},
         "features": {
             "command": sys.executable,  # Use the same Python that's running this script
             "args": ["-m", "mcp_server.feature_mcp"],
@@ -165,7 +167,23 @@ def create_client(project_dir: Path, model: str):
                 "PYTHONPATH": str(Path(__file__).parent.resolve()),
             },
         },
-            },
+    }
+    if not yolo_mode:
+        # Include Playwright MCP server for browser automation (standard mode only)
+        mcp_servers["playwright"] = {
+            "command": "npx",
+            "args": ["@playwright/mcp@latest", "--viewport-size", "1280x720"],
+        }
+
+    return ClaudeSDKClient(
+        options=ClaudeAgentOptions(
+            model=model,
+            cli_path=system_cli,  # Use system CLI to avoid bundled Bun crash (exit code 3)
+            system_prompt="You are an expert full-stack developer building a production-quality web application.",
+            setting_sources=["project"],  # Enable skills, commands, and CLAUDE.md from project dir
+            max_buffer_size=10 * 1024 * 1024,  # 10MB for large Playwright screenshots
+            allowed_tools=allowed_tools,
+            mcp_servers=mcp_servers,
             hooks={
                 "PreToolUse": [
                     HookMatcher(matcher="Bash", hooks=[bash_security_hook]),

prompts.py

@@ -75,6 +75,11 @@ def get_coding_prompt(project_dir: Path | None = None) -> str:
     return load_prompt("coding_prompt", project_dir)
 
 
+def get_coding_prompt_yolo(project_dir: Path | None = None) -> str:
+    """Load the YOLO mode coding agent prompt (project-specific if available)."""
+    return load_prompt("coding_prompt_yolo", project_dir)
+
+
 def get_app_spec(project_dir: Path) -> str:
     """
     Load the app spec from the project.
@@ -131,6 +136,7 @@ def scaffold_project_prompts(project_dir: Path) -> Path:
     templates = [
         ("app_spec.template.txt", "app_spec.txt"),
         ("coding_prompt.template.md", "coding_prompt.md"),
+        ("coding_prompt_yolo.template.md", "coding_prompt_yolo.md"),
         ("initializer_prompt.template.md", "initializer_prompt.md"),
     ]
 

server/routers/agent.py

@@ -11,7 +11,7 @@ from pathlib import Path
 
 from fastapi import APIRouter, HTTPException
 
-from ..schemas import AgentStatus, AgentActionResponse
+from ..schemas import AgentStatus, AgentActionResponse, AgentStartRequest
 from ..services.process_manager import get_manager
 
 
@@ -68,15 +68,19 @@ async def get_agent_status(project_name: str):
         status=manager.status,
         pid=manager.pid,
         started_at=manager.started_at,
+        yolo_mode=manager.yolo_mode,
     )
 
 
 @router.post("/start", response_model=AgentActionResponse)
-async def start_agent(project_name: str):
+async def start_agent(
+    project_name: str,
+    request: AgentStartRequest = AgentStartRequest(),
+):
     """Start the agent for a project."""
     manager = get_project_manager(project_name)
 
-    success, message = await manager.start()
+    success, message = await manager.start(yolo_mode=request.yolo_mode)
 
     return AgentActionResponse(
         success=success,

server/schemas.py

@@ -99,11 +99,17 @@ class FeatureListResponse(BaseModel):
 # Agent Schemas
 # ============================================================================
 
+class AgentStartRequest(BaseModel):
+    """Request schema for starting the agent."""
+    yolo_mode: bool = False
+
+
 class AgentStatus(BaseModel):
     """Current agent status."""
     status: Literal["stopped", "running", "paused", "crashed"]
     pid: int | None = None
     started_at: datetime | None = None
+    yolo_mode: bool = False
 
 
 class AgentActionResponse(BaseModel):

server/services/process_manager.py

@@ -74,6 +74,7 @@ class AgentProcessManager:
         self._status: Literal["stopped", "running", "paused", "crashed"] = "stopped"
         self.started_at: datetime | None = None
         self._output_task: asyncio.Task | None = None
+        self.yolo_mode: bool = False  # YOLO mode for rapid prototyping
 
         # Support multiple callbacks (for multiple WebSocket clients)
         self._output_callbacks: Set[Callable[[str], Awaitable[None]]] = set()
@@ -214,10 +215,13 @@ class AgentProcessManager:
                     self.status = "stopped"
                 self._remove_lock()
 
-    async def start(self) -> tuple[bool, str]:
+    async def start(self, yolo_mode: bool = False) -> tuple[bool, str]:
         """
         Start the agent as a subprocess.
 
+        Args:
+            yolo_mode: If True, run in YOLO mode (no browser testing)
+
         Returns:
             Tuple of (success, message)
         """
@@ -227,6 +231,9 @@ class AgentProcessManager:
         if not self._check_lock():
             return False, "Another agent instance is already running for this project"
 
+        # Store YOLO mode for status queries
+        self.yolo_mode = yolo_mode
+
         # Build command - pass absolute path to project directory
         cmd = [
             sys.executable,
@@ -235,6 +242,10 @@ class AgentProcessManager:
             str(self.project_dir.resolve()),
         ]
 
+        # Add --yolo flag if YOLO mode is enabled
+        if yolo_mode:
+            cmd.append("--yolo")
+
         try:
             # Start subprocess with piped stdout/stderr
             # Use project_dir as cwd so Claude SDK sandbox allows access to project files
@@ -295,6 +306,7 @@ class AgentProcessManager:
             self.status = "stopped"
             self.process = None
             self.started_at = None
+            self.yolo_mode = False  # Reset YOLO mode
 
             return True, "Agent stopped"
         except Exception as e:
@@ -375,6 +387,7 @@ class AgentProcessManager:
             "status": self.status,
             "pid": self.pid,
             "started_at": self.started_at.isoformat() if self.started_at else None,
+            "yolo_mode": self.yolo_mode,
         }
 
 

server/services/spec_chat_session.py

@@ -7,6 +7,7 @@ Uses the create-spec.md skill to guide users through app spec creation.
 """
 
 import asyncio
+import json
 import logging
 import shutil
 import threading
@@ -87,6 +88,33 @@ class SpecChatSession:
         # Ensure project directory exists (like CLI does in start.py)
         self.project_dir.mkdir(parents=True, exist_ok=True)
 
+        # Delete app_spec.txt so Claude can create it fresh
+        # The SDK requires reading existing files before writing, but app_spec.txt is created new
+        # Note: We keep initializer_prompt.md so Claude can read and update the template
+        prompts_dir = self.project_dir / "prompts"
+        app_spec_path = prompts_dir / "app_spec.txt"
+        if app_spec_path.exists():
+            app_spec_path.unlink()
+            logger.info("Deleted scaffolded app_spec.txt for fresh spec creation")
+
+        # Create security settings file (like client.py does)
+        # This grants permissions for file operations in the project directory
+        security_settings = {
+            "sandbox": {"enabled": False},  # Disable sandbox for spec creation
+            "permissions": {
+                "defaultMode": "acceptEdits",
+                "allow": [
+                    "Read(./**)",
+                    "Write(./**)",
+                    "Edit(./**)",
+                    "Glob(./**)",
+                ],
+            },
+        }
+        settings_file = self.project_dir / ".claude_settings.json"
+        with open(settings_file, "w") as f:
+            json.dump(security_settings, f, indent=2)
+
         # Replace $ARGUMENTS with absolute project path (like CLI does in start.py:184)
         # Using absolute path avoids confusion when project folder name differs from app name
         project_path = str(self.project_dir.resolve())
@@ -111,6 +139,7 @@ class SpecChatSession:
                     permission_mode="acceptEdits",  # Auto-approve file writes for spec creation
                     max_turns=100,
                     cwd=str(self.project_dir.resolve()),
+                    settings=str(settings_file.resolve()),
                 )
             )
             # Enter the async context and track it

ui/src/App.tsx

@@ -1,5 +1,5 @@
 import { useState, useEffect, useCallback } from 'react'
-import { useProjects, useFeatures } from './hooks/useProjects'
+import { useProjects, useFeatures, useAgentStatus } from './hooks/useProjects'
 import { useProjectWebSocket } from './hooks/useWebSocket'
 import { useFeatureSound } from './hooks/useFeatureSound'
 import { useCelebration } from './hooks/useCelebration'
@@ -34,6 +34,7 @@ function App() {
 
   const { data: projects, isLoading: projectsLoading } = useProjects()
   const { data: features } = useFeatures(selectedProject)
+  const { data: agentStatusData } = useAgentStatus(selectedProject)
   const wsState = useProjectWebSocket(selectedProject)
 
   // Play sounds when features move between columns
@@ -151,6 +152,7 @@ function App() {
                   <AgentControl
                     projectName={selectedProject}
                     status={wsState.agentStatus}
+                    yoloMode={agentStatusData?.yolo_mode ?? false}
                   />
                 </>
               )}

ui/src/components/AgentControl.tsx

@@ -1,4 +1,5 @@
-import { Play, Pause, Square, Loader2 } from 'lucide-react'
+import { useState } from 'react'
+import { Play, Pause, Square, Loader2, Zap } from 'lucide-react'
 import {
   useStartAgent,
   useStopAgent,
@@ -10,9 +11,12 @@ import type { AgentStatus } from '../lib/types'
 interface AgentControlProps {
   projectName: string
   status: AgentStatus
+  yoloMode?: boolean  // From server status - whether currently running in YOLO mode
 }
 
-export function AgentControl({ projectName, status }: AgentControlProps) {
+export function AgentControl({ projectName, status, yoloMode = false }: AgentControlProps) {
+  const [yoloEnabled, setYoloEnabled] = useState(false)
+
   const startAgent = useStartAgent(projectName)
   const stopAgent = useStopAgent(projectName)
   const pauseAgent = usePauseAgent(projectName)
@@ -24,7 +28,7 @@ export function AgentControl({ projectName, status }: AgentControlProps) {
     pauseAgent.isPending ||
     resumeAgent.isPending
 
-  const handleStart = () => startAgent.mutate()
+  const handleStart = () => startAgent.mutate(yoloEnabled)
   const handleStop = () => stopAgent.mutate()
   const handlePause = () => pauseAgent.mutate()
   const handleResume = () => resumeAgent.mutate()
@@ -34,14 +38,35 @@ export function AgentControl({ projectName, status }: AgentControlProps) {
       {/* Status Indicator */}
       <StatusIndicator status={status} />
 
+      {/* YOLO Mode Indicator - shown when running in YOLO mode */}
+      {(status === 'running' || status === 'paused') && yoloMode && (
+        <div className="flex items-center gap-1 px-2 py-1 bg-[var(--color-neo-pending)] border-3 border-[var(--color-neo-border)]">
+          <Zap size={14} className="text-yellow-900" />
+          <span className="font-display font-bold text-xs uppercase text-yellow-900">
+            YOLO
+          </span>
+        </div>
+      )}
+
       {/* Control Buttons */}
       <div className="flex gap-1">
         {status === 'stopped' || status === 'crashed' ? (
+          <>
+            {/* YOLO Toggle - only shown when stopped */}
+            <button
+              onClick={() => setYoloEnabled(!yoloEnabled)}
+              className={`neo-btn text-sm py-2 px-3 ${
+                yoloEnabled ? 'neo-btn-warning' : 'neo-btn-secondary'
+              }`}
+              title="YOLO Mode: Skip testing for rapid prototyping"
+            >
+              <Zap size={18} className={yoloEnabled ? 'text-yellow-900' : ''} />
+            </button>
             <button
               onClick={handleStart}
               disabled={isLoading}
               className="neo-btn neo-btn-success text-sm py-2 px-3"
-            title="Start Agent"
+              title={yoloEnabled ? "Start Agent (YOLO Mode)" : "Start Agent"}
             >
               {isLoading ? (
                 <Loader2 size={18} className="animate-spin" />
@@ -49,6 +74,7 @@ export function AgentControl({ projectName, status }: AgentControlProps) {
                 <Play size={18} />
               )}
             </button>
+          </>
         ) : status === 'running' ? (
           <>
             <button

ui/src/components/NewProjectModal.tsx

@@ -39,6 +39,7 @@ export function NewProjectModal({
   const [error, setError] = useState<string | null>(null)
   const [initializerStatus, setInitializerStatus] = useState<InitializerStatus>('idle')
   const [initializerError, setInitializerError] = useState<string | null>(null)
+  const [yoloModeSelected, setYoloModeSelected] = useState(false)
 
   // Suppress unused variable warning - specMethod may be used in future
   void _specMethod
@@ -116,11 +117,13 @@ export function NewProjectModal({
     }
   }
 
-  const handleSpecComplete = async () => {
+  const handleSpecComplete = async (_specPath: string, yoloMode: boolean = false) => {
+    // Save yoloMode for retry
+    setYoloModeSelected(yoloMode)
     // Auto-start the initializer agent
     setInitializerStatus('starting')
     try {
-      await startAgent(projectName.trim())
+      await startAgent(projectName.trim(), yoloMode)
       // Success - navigate to project
       setStep('complete')
       setTimeout(() => {
@@ -136,7 +139,7 @@ export function NewProjectModal({
   const handleRetryInitializer = () => {
     setInitializerError(null)
     setInitializerStatus('idle')
-    handleSpecComplete()
+    handleSpecComplete('', yoloModeSelected)
   }
 
   const handleChatCancel = () => {
@@ -153,6 +156,7 @@ export function NewProjectModal({
     setError(null)
     setInitializerStatus('idle')
     setInitializerError(null)
+    setYoloModeSelected(false)
     onClose()
   }
 

ui/src/components/SpecCreationChat.tsx

@@ -6,7 +6,7 @@
  */
 
 import { useEffect, useRef, useState } from 'react'
-import { Send, X, CheckCircle2, AlertCircle, Wifi, WifiOff, RotateCcw, Loader2, ArrowRight } from 'lucide-react'
+import { Send, X, CheckCircle2, AlertCircle, Wifi, WifiOff, RotateCcw, Loader2, ArrowRight, Zap } from 'lucide-react'
 import { useSpecChat } from '../hooks/useSpecChat'
 import { ChatMessage } from './ChatMessage'
 import { QuestionOptions } from './QuestionOptions'
@@ -16,7 +16,7 @@ type InitializerStatus = 'idle' | 'starting' | 'error'
 
 interface SpecCreationChatProps {
   projectName: string
-  onComplete: (specPath: string) => void
+  onComplete: (specPath: string, yoloMode?: boolean) => void
   onCancel: () => void
   initializerStatus?: InitializerStatus
   initializerError?: string | null
@@ -33,6 +33,7 @@ export function SpecCreationChat({
 }: SpecCreationChatProps) {
   const [input, setInput] = useState('')
   const [error, setError] = useState<string | null>(null)
+  const [yoloEnabled, setYoloEnabled] = useState(false)
   const messagesEndRef = useRef<HTMLDivElement>(null)
   const inputRef = useRef<HTMLInputElement>(null)
 
@@ -257,7 +258,9 @@ export function SpecCreationChat({
               {initializerStatus === 'starting' ? (
                 <>
                   <Loader2 size={20} className="animate-spin" />
-                  <span className="font-bold">Starting agent...</span>
+                  <span className="font-bold">
+                    Starting agent{yoloEnabled ? ' (YOLO mode)' : ''}...
+                  </span>
                 </>
               ) : initializerStatus === 'error' ? (
                 <>
@@ -284,13 +287,28 @@ export function SpecCreationChat({
                 </button>
               )}
               {initializerStatus === 'idle' && (
+                <>
+                  {/* YOLO Mode Toggle */}
                   <button
-                  onClick={() => onComplete('')}
+                    onClick={() => setYoloEnabled(!yoloEnabled)}
+                    className={`neo-btn text-sm py-2 px-3 ${
+                      yoloEnabled ? 'neo-btn-warning' : 'bg-white'
+                    }`}
+                    title="YOLO Mode: Skip testing for rapid prototyping"
+                  >
+                    <Zap size={16} className={yoloEnabled ? 'text-yellow-900' : ''} />
+                    <span className={yoloEnabled ? 'text-yellow-900 font-bold' : ''}>
+                      YOLO
+                    </span>
+                  </button>
+                  <button
+                    onClick={() => onComplete('', yoloEnabled)}
                     className="neo-btn neo-btn-primary"
                   >
                     Continue to Project
                     <ArrowRight size={16} />
                   </button>
+                </>
               )}
             </div>
           </div>

ui/src/hooks/useProjects.ts

@@ -111,7 +111,7 @@ export function useStartAgent(projectName: string) {
   const queryClient = useQueryClient()
 
   return useMutation({
-    mutationFn: () => api.startAgent(projectName),
+    mutationFn: (yoloMode: boolean = false) => api.startAgent(projectName, yoloMode),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['agent-status', projectName] })
     },

ui/src/lib/api.ts

@@ -117,9 +117,13 @@ export async function getAgentStatus(projectName: string): Promise<AgentStatusRe
   return fetchJSON(`/projects/${encodeURIComponent(projectName)}/agent/status`)
 }
 
-export async function startAgent(projectName: string): Promise<AgentActionResponse> {
+export async function startAgent(
+  projectName: string,
+  yoloMode: boolean = false
+): Promise<AgentActionResponse> {
   return fetchJSON(`/projects/${encodeURIComponent(projectName)}/agent/start`, {
     method: 'POST',
+    body: JSON.stringify({ yolo_mode: yoloMode }),
   })
 }
 

ui/src/lib/types.ts

@@ -89,6 +89,7 @@ export interface AgentStatusResponse {
   status: AgentStatus
   pid: number | null
   started_at: string | null
+  yolo_mode: boolean
 }
 
 export interface AgentActionResponse {