# AI Auto-Fix & Gemini Flash Provider Implementation Plan

> **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.

**Goal:** Add Gemini 2.5 Flash as primary AI provider (with Claude fallback), then build an AI-powered "Fix with AI" feature that generates structural fixes for validation errors in the tree editor.

**Architecture:** A provider abstraction layer (`ai_provider.py`) wraps Gemini and Anthropic SDKs behind a unified `generate_json()` interface. The existing `ai_tree_generator_service.py` swaps its direct Anthropic calls for this abstraction. A new `ai_fix_service.py` builds prompts from validation errors + tree context and returns proposed node patches. The frontend adds a "Fix with AI" button to `ValidationSummary` and a review modal for applying fixes.

**Tech Stack:** Python FastAPI, google-genai SDK, anthropic SDK, Pydantic v2, React 19, TypeScript, Zustand, Tailwind CSS

**Design Doc:** `docs/plans/2026-02-26-ai-autofix-gemini-design.md`

---

## Task 1: Install google-genai SDK

**Files:**
- Modify: `backend/requirements.txt`

**Step 1: Add the dependency**

Add `google-genai` to `backend/requirements.txt`:

```
google-genai>=1.0.0
```

**Step 2: Install it**

Run: `cd backend && pip install google-genai`

**Step 3: Commit**

```bash
git add backend/requirements.txt
git commit -m "chore: add google-genai SDK dependency"
```

---

## Task 2: Add Gemini config vars to Settings

**Files:**
- Modify: `backend/app/core/config.py:75-85`

**Step 1: Add new config variables**

In `backend/app/core/config.py`, after line 80 (`AI_REQUEST_TIMEOUT_SECONDS`), add:

```python
    # AI Provider selection
    AI_PROVIDER: str = "gemini"  # "gemini" or "anthropic"
    GOOGLE_AI_API_KEY: Optional[str] = None
    AI_MODEL_GEMINI: str = "gemini-2.5-flash"
    AI_MODEL_ANTHROPIC: str = "claude-haiku-4-5-20251001"
```

**Step 2: Update `ai_enabled` property**

Replace the existing `ai_enabled` property (lines 82-85) with:

```python
    @property
    def ai_enabled(self) -> bool:
        """Check if any AI provider is configured."""
        return self.ANTHROPIC_API_KEY is not None or self.GOOGLE_AI_API_KEY is not None
```

**Step 3: Verify no tests break**

Run: `cd backend && python -m pytest tests/test_ai_tree_validator.py -v`
Expected: All pass (config changes don't affect validator tests).

**Step 4: Commit**

```bash
git add backend/app/core/config.py
git commit -m "feat: add Gemini Flash config vars to Settings"
```

---

## Task 3: Build the AI provider abstraction

**Files:**
- Create: `backend/app/core/ai_provider.py`
- Test: `backend/tests/test_ai_provider.py`

**Step 1: Write tests for the provider abstraction**

Create `backend/tests/test_ai_provider.py`:

```python
"""Tests for AI provider abstraction layer."""
import pytest
from unittest.mock import AsyncMock, patch, MagicMock

from app.core.config import settings


class TestGetAIProvider:
    """Test provider factory function."""

    def test_returns_gemini_when_configured(self):
        original_provider = settings.AI_PROVIDER
        original_key = settings.GOOGLE_AI_API_KEY
        settings.AI_PROVIDER = "gemini"
        settings.GOOGLE_AI_API_KEY = "fake-gemini-key"
        try:
            from app.core.ai_provider import get_ai_provider, GeminiProvider
            provider = get_ai_provider()
            assert isinstance(provider, GeminiProvider)
        finally:
            settings.AI_PROVIDER = original_provider
            settings.GOOGLE_AI_API_KEY = original_key

    def test_returns_anthropic_when_configured(self):
        original_provider = settings.AI_PROVIDER
        original_key = settings.ANTHROPIC_API_KEY
        settings.AI_PROVIDER = "anthropic"
        settings.ANTHROPIC_API_KEY = "fake-anthropic-key"
        try:
            from app.core.ai_provider import get_ai_provider, AnthropicProvider
            provider = get_ai_provider()
            assert isinstance(provider, AnthropicProvider)
        finally:
            settings.AI_PROVIDER = original_provider
            settings.ANTHROPIC_API_KEY = original_key

    def test_falls_back_to_anthropic_when_gemini_key_missing(self):
        original_provider = settings.AI_PROVIDER
        original_gemini_key = settings.GOOGLE_AI_API_KEY
        original_anthropic_key = settings.ANTHROPIC_API_KEY
        settings.AI_PROVIDER = "gemini"
        settings.GOOGLE_AI_API_KEY = None
        settings.ANTHROPIC_API_KEY = "fake-anthropic-key"
        try:
            from app.core.ai_provider import get_ai_provider, AnthropicProvider
            provider = get_ai_provider()
            assert isinstance(provider, AnthropicProvider)
        finally:
            settings.AI_PROVIDER = original_provider
            settings.GOOGLE_AI_API_KEY = original_gemini_key
            settings.ANTHROPIC_API_KEY = original_anthropic_key

    def test_raises_when_no_provider_configured(self):
        original_provider = settings.AI_PROVIDER
        original_gemini_key = settings.GOOGLE_AI_API_KEY
        original_anthropic_key = settings.ANTHROPIC_API_KEY
        settings.AI_PROVIDER = "gemini"
        settings.GOOGLE_AI_API_KEY = None
        settings.ANTHROPIC_API_KEY = None
        try:
            from app.core.ai_provider import get_ai_provider
            with pytest.raises(RuntimeError, match="No AI provider configured"):
                get_ai_provider()
        finally:
            settings.AI_PROVIDER = original_provider
            settings.GOOGLE_AI_API_KEY = original_gemini_key
            settings.ANTHROPIC_API_KEY = original_anthropic_key


class TestAnthropicProvider:
    """Test Anthropic provider generate_json."""

    @pytest.mark.asyncio
    async def test_generate_json_returns_text_and_tokens(self):
        from app.core.ai_provider import AnthropicProvider

        mock_response = MagicMock()
        mock_response.content = [MagicMock(text='{"key": "value"}')]
        mock_response.usage = MagicMock(input_tokens=100, output_tokens=50)

        mock_client = AsyncMock()
        mock_client.messages.create = AsyncMock(return_value=mock_response)

        with patch("app.core.ai_provider.anthropic.AsyncAnthropic", return_value=mock_client):
            provider = AnthropicProvider(api_key="fake-key")
            text, inp, out = await provider.generate_json(
                system_prompt="You are a helper.",
                messages=[{"role": "user", "content": "Hello"}],
                max_tokens=1024,
            )
            assert text == '{"key": "value"}'
            assert inp == 100
            assert out == 50


class TestGeminiProvider:
    """Test Gemini provider generate_json."""

    @pytest.mark.asyncio
    async def test_generate_json_returns_text_and_tokens(self):
        from app.core.ai_provider import GeminiProvider

        mock_response = MagicMock()
        mock_response.text = '{"key": "value"}'
        mock_response.usage_metadata = MagicMock(
            prompt_token_count=100,
            candidates_token_count=50,
        )

        mock_client = MagicMock()
        mock_model = MagicMock()
        mock_model.generate_content_async = AsyncMock(return_value=mock_response)
        mock_client.models = mock_model

        with patch("app.core.ai_provider.genai.Client", return_value=mock_client):
            provider = GeminiProvider(api_key="fake-key")
            text, inp, out = await provider.generate_json(
                system_prompt="You are a helper.",
                messages=[{"role": "user", "content": "Hello"}],
                max_tokens=1024,
            )
            assert text == '{"key": "value"}'
            assert inp == 100
            assert out == 50
```

**Step 2: Run tests to verify they fail**

Run: `cd backend && python -m pytest tests/test_ai_provider.py -v`
Expected: ImportError — `ai_provider` module doesn't exist yet.

**Step 3: Implement the provider abstraction**

Create `backend/app/core/ai_provider.py`:

```python
"""AI provider abstraction layer.

Supports Gemini (default) and Anthropic (fallback) behind a unified interface.
"""
import logging
from abc import ABC, abstractmethod
from typing import Any

import anthropic
from google import genai
from google.genai import types as genai_types

from app.core.config import settings

logger = logging.getLogger(__name__)


class AIProvider(ABC):
    """Base class for AI providers."""

    @abstractmethod
    async def generate_json(
        self,
        system_prompt: str,
        messages: list[dict[str, str]],
        max_tokens: int = 4096,
    ) -> tuple[str, int, int]:
        """Generate a JSON response from the AI model.

        Args:
            system_prompt: System instructions for the model.
            messages: List of {"role": "user"|"assistant", "content": str} dicts.
            max_tokens: Maximum output tokens.

        Returns:
            (response_text, input_tokens, output_tokens)
        """
        ...


class GeminiProvider(AIProvider):
    """Google Gemini provider using google-genai SDK."""

    def __init__(self, api_key: str, model: str | None = None):
        self._api_key = api_key
        self._model = model or settings.AI_MODEL_GEMINI

    async def generate_json(
        self,
        system_prompt: str,
        messages: list[dict[str, str]],
        max_tokens: int = 4096,
    ) -> tuple[str, int, int]:
        client = genai.Client(api_key=self._api_key)

        # Build contents: system instruction is separate in Gemini API
        contents: list[genai_types.Content] = []
        for msg in messages:
            role = "user" if msg["role"] == "user" else "model"
            contents.append(genai_types.Content(
                role=role,
                parts=[genai_types.Part(text=msg["content"])],
            ))

        config = genai_types.GenerateContentConfig(
            system_instruction=system_prompt,
            max_output_tokens=max_tokens,
            response_mime_type="application/json",
        )

        response = await client.models.generate_content_async(
            model=self._model,
            contents=contents,
            config=config,
        )

        text = response.text or ""
        input_tokens = getattr(response.usage_metadata, "prompt_token_count", 0) or 0
        output_tokens = getattr(response.usage_metadata, "candidates_token_count", 0) or 0

        return text, input_tokens, output_tokens


class AnthropicProvider(AIProvider):
    """Anthropic Claude provider."""

    def __init__(self, api_key: str, model: str | None = None):
        self._api_key = api_key
        self._model = model or settings.AI_MODEL_ANTHROPIC

    async def generate_json(
        self,
        system_prompt: str,
        messages: list[dict[str, str]],
        max_tokens: int = 4096,
    ) -> tuple[str, int, int]:
        client = anthropic.AsyncAnthropic(
            api_key=self._api_key,
            timeout=settings.AI_REQUEST_TIMEOUT_SECONDS,
        )

        response = await client.messages.create(
            model=self._model,
            max_tokens=max_tokens,
            system=system_prompt,
            messages=messages,
        )

        text = response.content[0].text
        input_tokens = response.usage.input_tokens
        output_tokens = response.usage.output_tokens

        return text, input_tokens, output_tokens


def get_ai_provider() -> AIProvider:
    """Factory: return the configured AI provider.

    Falls back to Anthropic if Gemini key is missing.
    Raises RuntimeError if no provider is configured.
    """
    if settings.AI_PROVIDER == "gemini" and settings.GOOGLE_AI_API_KEY:
        logger.info("Using Gemini provider (%s)", settings.AI_MODEL_GEMINI)
        return GeminiProvider(api_key=settings.GOOGLE_AI_API_KEY)

    if settings.AI_PROVIDER == "anthropic" and settings.ANTHROPIC_API_KEY:
        logger.info("Using Anthropic provider (%s)", settings.AI_MODEL_ANTHROPIC)
        return AnthropicProvider(api_key=settings.ANTHROPIC_API_KEY)

    # Fallback: if Gemini requested but key missing, try Anthropic
    if settings.ANTHROPIC_API_KEY:
        logger.warning("Gemini key missing, falling back to Anthropic provider")
        return AnthropicProvider(api_key=settings.ANTHROPIC_API_KEY)

    raise RuntimeError(
        "No AI provider configured. Set GOOGLE_AI_API_KEY or ANTHROPIC_API_KEY."
    )
```

**Step 4: Run tests to verify they pass**

Run: `cd backend && python -m pytest tests/test_ai_provider.py -v`
Expected: All pass.

**Step 5: Commit**

```bash
git add backend/app/core/ai_provider.py backend/tests/test_ai_provider.py
git commit -m "feat: add AI provider abstraction with Gemini and Anthropic support"
```

---

## Task 4: Migrate ai_tree_generator_service to use provider abstraction

**Files:**
- Modify: `backend/app/core/ai_tree_generator_service.py`
- Modify: `backend/app/api/endpoints/ai_builder.py`

**Step 1: Update ai_tree_generator_service.py**

In `backend/app/core/ai_tree_generator_service.py`:

Replace the import at line 16:
```python
# OLD
import anthropic
# NEW
from app.core.ai_provider import get_ai_provider
```

Remove the `_get_client()` function (lines 124-131).

Update `scaffold_branches()` (starting at line 141). Replace the client creation and API call:

```python
async def scaffold_branches(
    wizard_state: dict[str, Any],
) -> tuple[list[dict[str, str]], int, int, float]:
    """Stage 2: AI suggests top-level branches."""
    provider = get_ai_provider()

    flow_type = wizard_state.get("flow_type", "troubleshooting")
    name = wizard_state.get("name", "")
    description = wizard_state.get("description", "")
    tags = wizard_state.get("environment_tags", [])

    user_message = (
        f"Flow type: {flow_type}\n"
        f"Name: {name}\n"
        f"Description: {description}\n"
    )
    if tags:
        user_message += f"Environment: {', '.join(tags)}\n"

    raw_text, input_tokens, output_tokens = await provider.generate_json(
        system_prompt=SCAFFOLD_SYSTEM_PROMPT,
        messages=[{"role": "user", "content": user_message}],
        max_tokens=1024,
    )
```

Then update the rest of the function to use `raw_text` instead of `response.content[0].text`, and `input_tokens`/`output_tokens` directly instead of `response.usage.*`.

Do the same for `generate_branch_detail()` — replace `_get_client()` + `client.messages.create()` with `provider.generate_json()`. The retry loop structure stays the same; just swap the API call and response parsing.

**Step 2: Update ai_builder.py endpoint**

In `backend/app/api/endpoints/ai_builder.py`, line 13:

```python
# OLD
import anthropic
# NEW (remove this import entirely — no longer needed in the endpoint file)
```

Update the `_require_ai_enabled()` function (line 50) to check the new config:

```python
def _require_ai_enabled() -> None:
    if not settings.ai_enabled:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="AI Flow Builder is not configured. Set GOOGLE_AI_API_KEY or ANTHROPIC_API_KEY.",
        )
```

Update any `except anthropic.APIError` catch blocks in the endpoint to catch generic `Exception` or a broader error type, since the provider abstraction may raise different errors depending on backend.

**Step 3: Run existing AI endpoint tests**

Run: `cd backend && python -m pytest tests/test_ai_endpoints.py -v`

These tests mock `anthropic.AsyncAnthropic` — they need to be updated to mock `app.core.ai_provider.get_ai_provider` instead. Update the mock targets in the test file:

```python
# Replace patches like:
# @patch("app.core.ai_tree_generator_service._get_client")
# With:
# @patch("app.core.ai_tree_generator_service.get_ai_provider")
```

The mock provider should return an `AsyncMock` that returns `(json_text, input_tokens, output_tokens)` from `generate_json`.

**Step 4: Verify all tests pass**

Run: `cd backend && python -m pytest tests/test_ai_endpoints.py tests/test_ai_provider.py tests/test_ai_tree_validator.py -v`
Expected: All pass.

**Step 5: Commit**

```bash
git add backend/app/core/ai_tree_generator_service.py backend/app/api/endpoints/ai_builder.py backend/tests/test_ai_endpoints.py
git commit -m "refactor: migrate AI tree generator to provider abstraction"
```

---

## Task 5: Create AI fix schemas

**Files:**
- Create: `backend/app/schemas/ai_fix.py`

**Step 1: Create the schemas**

Create `backend/app/schemas/ai_fix.py`:

```python
"""Pydantic schemas for the AI auto-fix feature."""
from typing import Any, Literal

from pydantic import BaseModel, Field


class ValidationErrorInput(BaseModel):
    """A single validation error to fix."""

    node_id: str = Field(..., description="ID of the node with the error")
    message: str = Field(..., description="The validation error message")


class AIFixTreeRequest(BaseModel):
    """Request to generate AI fixes for validation errors."""

    tree_structure: dict[str, Any] = Field(..., description="Full tree structure")
    tree_name: str = Field("", max_length=255, description="Name of the flow")
    tree_type: Literal["troubleshooting", "procedural", "maintenance"] = Field(
        "troubleshooting", description="Type of flow"
    )
    validation_errors: list[ValidationErrorInput] = Field(
        ..., min_length=1, max_length=10, description="Errors to fix"
    )


class AIFixProposal(BaseModel):
    """A single proposed fix from the AI."""

    target_node_id: str
    error_message: str
    description: str
    original_node: dict[str, Any]
    fixed_node: dict[str, Any]


class AIFixTokenUsage(BaseModel):
    input: int = 0
    output: int = 0


class AIFixTreeResponse(BaseModel):
    """Response with proposed fixes."""

    fixes: list[AIFixProposal]
    tokens_used: AIFixTokenUsage
```

**Step 2: Commit**

```bash
git add backend/app/schemas/ai_fix.py
git commit -m "feat: add Pydantic schemas for AI fix-tree endpoint"
```

---

## Task 6: Build the AI fix service

**Files:**
- Create: `backend/app/core/ai_fix_service.py`
- Test: `backend/tests/test_ai_fix_service.py`

**Step 1: Write tests**

Create `backend/tests/test_ai_fix_service.py`:

```python
"""Tests for AI fix service — prompt building and node extraction."""
import json
import pytest
from app.core.ai_fix_service import _serialize_tree_outline, _find_node_by_id, _find_parent_node


def _make_tree():
    return {
        "id": "root",
        "type": "decision",
        "question": "Is the server up?",
        "options": [
            {"id": "opt-yes", "label": "Yes", "next_node_id": "check-logs"},
            {"id": "opt-no", "label": "No", "next_node_id": "restart"},
        ],
        "children": [
            {
                "id": "check-logs",
                "type": "action",
                "title": "Check Logs",
                "description": "Review event logs.",
                "next_node_id": "logs-ok",
            },
            {
                "id": "logs-ok",
                "type": "solution",
                "title": "Logs Resolved",
                "description": "Found issue in logs.",
            },
            {
                "id": "restart",
                "type": "decision",
                "question": "Did restart fix it?",
                "options": [
                    {"id": "opt-r-yes", "label": "Yes", "next_node_id": "restart-ok"},
                ],
                "children": [
                    {
                        "id": "restart-ok",
                        "type": "solution",
                        "title": "Restart Worked",
                        "description": "Server is back.",
                    },
                ],
            },
        ],
    }


class TestFindNodeById:
    def test_finds_root(self):
        tree = _make_tree()
        node = _find_node_by_id(tree, "root")
        assert node is not None
        assert node["id"] == "root"

    def test_finds_nested_child(self):
        tree = _make_tree()
        node = _find_node_by_id(tree, "restart-ok")
        assert node is not None
        assert node["id"] == "restart-ok"

    def test_returns_none_for_missing(self):
        tree = _make_tree()
        assert _find_node_by_id(tree, "nonexistent") is None


class TestFindParentNode:
    def test_root_has_no_parent(self):
        tree = _make_tree()
        assert _find_parent_node(tree, "root") is None

    def test_finds_parent_of_child(self):
        tree = _make_tree()
        parent = _find_parent_node(tree, "restart")
        assert parent is not None
        assert parent["id"] == "root"

    def test_finds_parent_of_deeply_nested(self):
        tree = _make_tree()
        parent = _find_parent_node(tree, "restart-ok")
        assert parent is not None
        assert parent["id"] == "restart"


class TestSerializeTreeOutline:
    def test_produces_readable_outline(self):
        tree = _make_tree()
        outline = _serialize_tree_outline(tree)
        assert "[decision] Is the server up?" in outline
        assert "[action] Check Logs" in outline
        assert "[solution] Restart Worked" in outline

    def test_marks_error_node(self):
        tree = _make_tree()
        outline = _serialize_tree_outline(tree, error_node_id="restart")
        assert "ERROR HERE" in outline
```

**Step 2: Run tests to verify they fail**

Run: `cd backend && python -m pytest tests/test_ai_fix_service.py -v`
Expected: ImportError — module doesn't exist.

**Step 3: Implement the fix service**

Create `backend/app/core/ai_fix_service.py`:

```python
"""AI-powered fix generation for tree validation errors.

Builds targeted prompts for each failing node, sends to the AI provider,
and validates the fix before returning it.
"""
import copy
import json
import logging
import re
from typing import Any

from app.core.ai_provider import get_ai_provider
from app.core.ai_tree_validator import validate_generated_tree

logger = logging.getLogger(__name__)

# ── Helpers ──


def _find_node_by_id(tree: dict[str, Any], node_id: str) -> dict[str, Any] | None:
    """Recursively find a node by ID in the tree."""
    if not isinstance(tree, dict):
        return None
    if tree.get("id") == node_id:
        return tree
    for child in tree.get("children", []):
        result = _find_node_by_id(child, node_id)
        if result is not None:
            return result
    return None


def _find_parent_node(tree: dict[str, Any], target_id: str) -> dict[str, Any] | None:
    """Find the parent of the node with target_id."""
    if not isinstance(tree, dict):
        return None
    for child in tree.get("children", []):
        if isinstance(child, dict) and child.get("id") == target_id:
            return tree
        result = _find_parent_node(child, target_id)
        if result is not None:
            return result
    return None


def _serialize_tree_outline(
    tree: dict[str, Any],
    indent: int = 0,
    error_node_id: str | None = None,
) -> str:
    """Serialize tree as a compact readable outline for the AI prompt."""
    if not isinstance(tree, dict):
        return ""

    node_type = tree.get("type", "?")
    label = tree.get("question") or tree.get("title") or tree.get("id", "?")
    prefix = "  " * indent
    marker = " <<< ERROR HERE" if tree.get("id") == error_node_id else ""

    line = f"{prefix}- [{node_type}] {label}{marker}"
    lines = [line]

    for child in tree.get("children", []):
        lines.append(_serialize_tree_outline(child, indent + 1, error_node_id))

    return "\n".join(lines)


def _strip_markdown_fences(text: str) -> str:
    """Strip ```json ... ``` fences from AI response."""
    match = re.search(r"```(?:json)?\s*\n?(.*?)\n?\s*```", text, re.DOTALL)
    if match:
        return match.group(1).strip()
    return text


# ── Prompt ──

FIX_SYSTEM_PROMPT = """You are ResolutionFlow AI, fixing structural validation errors in IT troubleshooting and maintenance flows used by MSP engineers.

You will receive:
1. A full flow outline showing the tree structure
2. The specific failing node with its full JSON
3. The validation error message

Your task: Return a FIXED version of the failing node as valid JSON. Rules:
- Fix ONLY the structural issue described in the error message
- Keep ALL existing content (titles, descriptions, questions, options) unchanged
- When adding new nodes (e.g., missing branches), generate domain-relevant content that fits the flow's topic
- Every new node must have a unique ID (use descriptive kebab-case IDs)
- Decision nodes must have at least 2 options and at least 2 children
- Action nodes must have a next_node_id pointing to a sibling node in the parent's children
- Solution nodes are leaf nodes (no children)
- Return ONLY the fixed node JSON, no explanation"""


def _build_fix_prompt(
    tree: dict[str, Any],
    node_id: str,
    error_message: str,
    tree_name: str,
    tree_type: str,
) -> str:
    """Build the user message for fixing a specific node."""
    outline = _serialize_tree_outline(tree, error_node_id=node_id)
    failing_node = _find_node_by_id(tree, node_id)
    node_json = json.dumps(failing_node, indent=2) if failing_node else "{}"

    return (
        f"Flow name: {tree_name}\n"
        f"Flow type: {tree_type}\n\n"
        f"FULL FLOW OUTLINE:\n{outline}\n\n"
        f"ERROR: {error_message}\n\n"
        f"FAILING NODE (full JSON):\n{node_json}\n\n"
        f"Return the fixed version of this node as JSON."
    )


# ── Main Service ──


async def generate_fixes(
    tree_structure: dict[str, Any],
    tree_name: str,
    tree_type: str,
    validation_errors: list[dict[str, str]],
) -> tuple[list[dict[str, Any]], int, int]:
    """Generate AI fixes for each validation error.

    Args:
        tree_structure: Full tree JSON.
        tree_name: Name of the flow.
        tree_type: Type of flow (troubleshooting/procedural/maintenance).
        validation_errors: List of {"node_id": str, "message": str}.

    Returns:
        (fixes, total_input_tokens, total_output_tokens)
        Each fix: {"target_node_id", "error_message", "description", "original_node", "fixed_node"}
    """
    provider = get_ai_provider()
    fixes: list[dict[str, Any]] = []
    total_input = 0
    total_output = 0

    for error in validation_errors:
        node_id = error["node_id"]
        error_message = error["message"]

        original_node = _find_node_by_id(tree_structure, node_id)
        if original_node is None:
            logger.warning("Node %s not found in tree, skipping fix", node_id)
            continue

        original_snapshot = copy.deepcopy(original_node)
        user_message = _build_fix_prompt(
            tree_structure, node_id, error_message, tree_name, tree_type
        )

        # Attempt fix (with 1 retry using corrective prompt)
        messages: list[dict[str, str]] = [{"role": "user", "content": user_message}]

        for attempt in range(2):
            try:
                raw_text, inp_tokens, out_tokens = await provider.generate_json(
                    system_prompt=FIX_SYSTEM_PROMPT,
                    messages=messages,
                    max_tokens=4096,
                )
                total_input += inp_tokens
                total_output += out_tokens

                cleaned = _strip_markdown_fences(raw_text)
                fixed_node = json.loads(cleaned)

                # Quick validation: check that the fix actually addresses the error
                # by substituting into tree and re-validating that specific error is gone
                test_tree = copy.deepcopy(tree_structure)
                _replace_node_in_tree(test_tree, node_id, fixed_node)
                remaining_errors = validate_generated_tree(test_tree)
                still_has_error = any(
                    node_id in e and error_message.split(":")[0].lower() in e.lower()
                    for e in remaining_errors
                )

                if still_has_error and attempt == 0:
                    # Retry with corrective prompt
                    messages.append({"role": "assistant", "content": raw_text})
                    messages.append({
                        "role": "user",
                        "content": (
                            f"The fix still has the same validation error. "
                            f"Remaining errors: {remaining_errors}. "
                            f"Please try again."
                        ),
                    })
                    continue

                # Extract description from the fix
                description = _describe_fix(original_snapshot, fixed_node)

                fixes.append({
                    "target_node_id": node_id,
                    "error_message": error_message,
                    "description": description,
                    "original_node": original_snapshot,
                    "fixed_node": fixed_node,
                })
                break

            except (json.JSONDecodeError, KeyError, TypeError) as exc:
                logger.warning(
                    "Fix attempt %d for node %s failed: %s", attempt + 1, node_id, exc
                )
                if attempt == 0:
                    messages.append({"role": "assistant", "content": raw_text if 'raw_text' in dir() else ""})
                    messages.append({
                        "role": "user",
                        "content": f"Invalid JSON response. Return ONLY valid JSON for the fixed node.",
                    })
                else:
                    logger.error("Failed to generate fix for node %s after 2 attempts", node_id)

    return fixes, total_input, total_output


def _replace_node_in_tree(
    tree: dict[str, Any], target_id: str, replacement: dict[str, Any]
) -> bool:
    """Replace a node in the tree by ID. Returns True if found and replaced."""
    if tree.get("id") == target_id:
        tree.clear()
        tree.update(replacement)
        return True
    for child in tree.get("children", []):
        if isinstance(child, dict):
            if child.get("id") == target_id:
                child.clear()
                child.update(replacement)
                return True
            if _replace_node_in_tree(child, target_id, replacement):
                return True
    return False


def _describe_fix(original: dict[str, Any], fixed: dict[str, Any]) -> str:
    """Generate a human-readable description of what changed."""
    orig_children = len(original.get("children", []))
    fixed_children = len(fixed.get("children", []))
    orig_options = len(original.get("options", []))
    fixed_options = len(fixed.get("options", []))

    parts: list[str] = []
    if fixed_children > orig_children:
        added = fixed_children - orig_children
        parts.append(f"Added {added} child node{'s' if added > 1 else ''}")
    if fixed_options > orig_options:
        added = fixed_options - orig_options
        parts.append(f"Added {added} option{'s' if added > 1 else ''}")
    if "next_node_id" in fixed and "next_node_id" not in original:
        parts.append(f"Added next_node_id '{fixed['next_node_id']}'")

    return "; ".join(parts) if parts else "Structural fix applied"
```

**Step 4: Run tests**

Run: `cd backend && python -m pytest tests/test_ai_fix_service.py -v`
Expected: All pass.

**Step 5: Commit**

```bash
git add backend/app/core/ai_fix_service.py backend/tests/test_ai_fix_service.py
git commit -m "feat: add AI fix service with prompt building and validation"
```

---

## Task 7: Create the fix-tree endpoint

**Files:**
- Create: `backend/app/api/endpoints/ai_fix.py`
- Modify: `backend/app/api/router.py`
- Test: `backend/tests/test_ai_fix_endpoint.py`

**Step 1: Write the endpoint test**

Create `backend/tests/test_ai_fix_endpoint.py`:

```python
"""Integration tests for AI fix-tree endpoint."""
import json
from unittest.mock import AsyncMock, patch

import pytest

from app.core.config import settings


SAMPLE_TREE = {
    "id": "root",
    "type": "decision",
    "question": "Is the server up?",
    "options": [
        {"id": "opt-yes", "label": "Yes", "next_node_id": "check-logs"},
        {"id": "opt-no", "label": "No", "next_node_id": "restart"},
    ],
    "children": [
        {
            "id": "check-logs",
            "type": "action",
            "title": "Check Logs",
            "description": "Review logs.",
            "next_node_id": "logs-ok",
        },
        {
            "id": "logs-ok",
            "type": "solution",
            "title": "Logs OK",
            "description": "Issue in logs.",
        },
        {
            "id": "restart",
            "type": "decision",
            "question": "Did restart work?",
            "options": [{"id": "opt-r", "label": "Yes", "next_node_id": "done"}],
            "children": [
                {"id": "done", "type": "solution", "title": "Done", "description": "Fixed."},
            ],
        },
    ],
}


@pytest.fixture
def enable_ai():
    original_key = settings.GOOGLE_AI_API_KEY
    original_provider = settings.AI_PROVIDER
    settings.GOOGLE_AI_API_KEY = "fake-key"
    settings.AI_PROVIDER = "gemini"
    yield
    settings.GOOGLE_AI_API_KEY = original_key
    settings.AI_PROVIDER = original_provider


@pytest.mark.asyncio
class TestFixTreeEndpoint:

    async def test_returns_401_without_auth(self, client):
        response = await client.post("/api/v1/ai/fix-tree", json={
            "tree_structure": SAMPLE_TREE,
            "tree_name": "Test",
            "tree_type": "troubleshooting",
            "validation_errors": [{"node_id": "restart", "message": "Need 2 options"}],
        })
        assert response.status_code == 401

    async def test_returns_503_when_ai_disabled(self, client, auth_headers):
        original = settings.GOOGLE_AI_API_KEY
        orig_anthropic = settings.ANTHROPIC_API_KEY
        settings.GOOGLE_AI_API_KEY = None
        settings.ANTHROPIC_API_KEY = None
        try:
            response = await client.post(
                "/api/v1/ai/fix-tree",
                json={
                    "tree_structure": SAMPLE_TREE,
                    "tree_name": "Test",
                    "tree_type": "troubleshooting",
                    "validation_errors": [{"node_id": "restart", "message": "test"}],
                },
                headers=auth_headers,
            )
            assert response.status_code == 503
        finally:
            settings.GOOGLE_AI_API_KEY = original
            settings.ANTHROPIC_API_KEY = orig_anthropic

    async def test_returns_fixes_on_success(self, client, auth_headers, enable_ai):
        fixed_node = {
            "id": "restart",
            "type": "decision",
            "question": "Did restart work?",
            "options": [
                {"id": "opt-r-yes", "label": "Yes", "next_node_id": "done"},
                {"id": "opt-r-no", "label": "No", "next_node_id": "escalate"},
            ],
            "children": [
                {"id": "done", "type": "solution", "title": "Done", "description": "Fixed."},
                {"id": "escalate", "type": "solution", "title": "Escalate", "description": "Escalate to vendor."},
            ],
        }

        mock_provider = AsyncMock()
        mock_provider.generate_json = AsyncMock(
            return_value=(json.dumps(fixed_node), 500, 300)
        )

        with patch("app.core.ai_fix_service.get_ai_provider", return_value=mock_provider):
            response = await client.post(
                "/api/v1/ai/fix-tree",
                json={
                    "tree_structure": SAMPLE_TREE,
                    "tree_name": "Server Flow",
                    "tree_type": "troubleshooting",
                    "validation_errors": [
                        {"node_id": "restart", "message": "Decision node must have at least 2 options"},
                    ],
                },
                headers=auth_headers,
            )

        assert response.status_code == 200
        data = response.json()
        assert len(data["fixes"]) == 1
        assert data["fixes"][0]["target_node_id"] == "restart"
        assert data["tokens_used"]["input"] == 500
        assert data["tokens_used"]["output"] == 300
```

**Step 2: Run to verify it fails**

Run: `cd backend && python -m pytest tests/test_ai_fix_endpoint.py -v`
Expected: Fail — endpoint doesn't exist.

**Step 3: Create the endpoint**

Create `backend/app/api/endpoints/ai_fix.py`:

```python
"""AI auto-fix endpoint for tree validation errors."""
import logging
from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, Request, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.rate_limit import limiter
from app.api.deps import get_current_active_user, get_db, require_engineer_or_admin
from app.core.config import settings
from app.core.ai_fix_service import generate_fixes
from app.models.user import User
from app.schemas.ai_fix import AIFixTreeRequest, AIFixTreeResponse, AIFixProposal, AIFixTokenUsage

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/ai", tags=["ai-fix"])


def _require_ai_enabled() -> None:
    if not settings.ai_enabled:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="AI is not configured. Set GOOGLE_AI_API_KEY or ANTHROPIC_API_KEY.",
        )


@router.post("/fix-tree", response_model=AIFixTreeResponse)
@limiter.limit("10/minute")
async def fix_tree(
    request: Request,
    body: AIFixTreeRequest,
    user: Annotated[User, Depends(require_engineer_or_admin)],
    db: Annotated[AsyncSession, Depends(get_db)],
):
    """Generate AI-powered fixes for tree validation errors."""
    _require_ai_enabled()

    try:
        fixes, total_input, total_output = await generate_fixes(
            tree_structure=body.tree_structure,
            tree_name=body.tree_name,
            tree_type=body.tree_type,
            validation_errors=[
                {"node_id": e.node_id, "message": e.message}
                for e in body.validation_errors
            ],
        )
    except RuntimeError as exc:
        logger.error("AI fix generation failed: %s", exc)
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail=str(exc),
        )
    except Exception as exc:
        logger.exception("Unexpected error during AI fix generation")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to generate fixes. Please try again.",
        )

    return AIFixTreeResponse(
        fixes=[
            AIFixProposal(
                target_node_id=f["target_node_id"],
                error_message=f["error_message"],
                description=f["description"],
                original_node=f["original_node"],
                fixed_node=f["fixed_node"],
            )
            for f in fixes
        ],
        tokens_used=AIFixTokenUsage(input=total_input, output=total_output),
    )
```

**Step 4: Register in router**

In `backend/app/api/router.py`, add:

After line 8 (`from app.api.endpoints import ai_builder`):
```python
from app.api.endpoints import ai_fix
```

After line 38 (`api_router.include_router(ai_builder.router)`):
```python
api_router.include_router(ai_fix.router)
```

**Step 5: Run tests**

Run: `cd backend && python -m pytest tests/test_ai_fix_endpoint.py -v`
Expected: All pass.

**Step 6: Run full test suite**

Run: `cd backend && python -m pytest --override-ini="addopts=" -v`
Expected: All pass (100+ tests).

**Step 7: Commit**

```bash
git add backend/app/api/endpoints/ai_fix.py backend/app/api/router.py backend/app/schemas/ai_fix.py backend/tests/test_ai_fix_endpoint.py
git commit -m "feat: add POST /ai/fix-tree endpoint for AI-powered validation fixes"
```

---

## Task 8: Add frontend API client for fix-tree

**Files:**
- Modify: `frontend/src/api/trees.ts`
- Create: `frontend/src/types/ai-fix.ts`
- Modify: `frontend/src/types/index.ts`

**Step 1: Create the types**

Create `frontend/src/types/ai-fix.ts`:

```typescript
export interface AIFixValidationError {
  node_id: string
  message: string
}

export interface AIFixProposal {
  target_node_id: string
  error_message: string
  description: string
  original_node: Record<string, unknown>
  fixed_node: Record<string, unknown>
}

export interface AIFixTreeRequest {
  tree_structure: Record<string, unknown>
  tree_name: string
  tree_type: 'troubleshooting' | 'procedural' | 'maintenance'
  validation_errors: AIFixValidationError[]
}

export interface AIFixTreeResponse {
  fixes: AIFixProposal[]
  tokens_used: { input: number; output: number }
}
```

**Step 2: Export from types/index.ts**

Add to `frontend/src/types/index.ts`:

```typescript
export type { AIFixTreeRequest, AIFixTreeResponse, AIFixProposal, AIFixValidationError } from './ai-fix'
```

**Step 3: Add API method to trees.ts**

In `frontend/src/api/trees.ts`, add a new method to the `treesApi` object:

```typescript
  async fixTree(request: AIFixTreeRequest): Promise<AIFixTreeResponse> {
    const response = await apiClient.post<AIFixTreeResponse>('/ai/fix-tree', request)
    return response.data
  },
```

Import the types at the top of the file.

**Step 4: Commit**

```bash
git add frontend/src/types/ai-fix.ts frontend/src/types/index.ts frontend/src/api/trees.ts
git commit -m "feat: add frontend API client and types for AI fix-tree"
```

---

## Task 9: Add "Fix with AI" button to ValidationSummary

**Files:**
- Modify: `frontend/src/components/tree-editor/ValidationSummary.tsx`

**Step 1: Update the component**

Add new props and the button to `ValidationSummary`:

```typescript
import { useState } from 'react'
import { AlertCircle, AlertTriangle, ChevronDown, ChevronUp, Sparkles, Loader2 } from 'lucide-react'
import { cn } from '@/lib/utils'
import type { ValidationError } from '@/store/treeEditorStore'

interface ValidationSummaryProps {
  errors: ValidationError[]
  onSelectNode: (nodeId: string) => void
  onFixWithAI?: () => void
  isFixing?: boolean
}

export function ValidationSummary({ errors, onSelectNode, onFixWithAI, isFixing }: ValidationSummaryProps) {
```

In the header button area (after the expand/collapse chevron at line 62), add the "Fix with AI" button. It should appear between the error count text and the chevron icon. Restructure the header to include the button:

After the `</span>` closing the error/warning count (around line 60), add:

```tsx
        {/* Fix with AI button — only when there are fixable errors */}
        {onFixWithAI && errorItems.some(e => e.nodeId) && (
          <button
            onClick={(e) => {
              e.stopPropagation()
              onFixWithAI()
            }}
            disabled={isFixing}
            className={cn(
              'ml-auto mr-2 flex items-center gap-1.5 rounded-md px-3 py-1 text-xs font-medium transition-colors',
              isFixing
                ? 'bg-primary/10 text-primary cursor-wait'
                : 'bg-gradient-brand text-white shadow-sm shadow-primary/20 hover:opacity-90'
            )}
          >
            {isFixing ? (
              <>
                <Loader2 className="h-3 w-3 animate-spin" />
                Generating fixes...
              </>
            ) : (
              <>
                <Sparkles className="h-3 w-3" />
                Fix with AI
              </>
            )}
          </button>
        )}
```

**Step 2: Build to verify**

Run: `cd frontend && npm run build`
Expected: Build passes.

**Step 3: Commit**

```bash
git add frontend/src/components/tree-editor/ValidationSummary.tsx
git commit -m "feat: add Fix with AI button to ValidationSummary"
```

---

## Task 10: Build the AIFixReviewModal

**Files:**
- Create: `frontend/src/components/tree-editor/AIFixReviewModal.tsx`

**Step 1: Create the review modal**

Create `frontend/src/components/tree-editor/AIFixReviewModal.tsx`:

```typescript
import { useState } from 'react'
import { X, Check, SkipForward, Sparkles, ChevronDown, ChevronUp } from 'lucide-react'
import { cn } from '@/lib/utils'
import type { AIFixProposal } from '@/types'

interface AIFixReviewModalProps {
  fixes: AIFixProposal[]
  onApply: (fix: AIFixProposal) => void
  onApplyAll: () => void
  onClose: () => void
}

export function AIFixReviewModal({ fixes, onApply, onApplyAll, onClose }: AIFixReviewModalProps) {
  const [appliedIds, setAppliedIds] = useState<Set<string>>(new Set())
  const [skippedIds, setSkippedIds] = useState<Set<string>>(new Set())
  const [expandedIds, setExpandedIds] = useState<Set<string>>(new Set(fixes.map(f => f.target_node_id)))

  const handleApply = (fix: AIFixProposal) => {
    onApply(fix)
    setAppliedIds(prev => new Set(prev).add(fix.target_node_id))
  }

  const handleSkip = (fix: AIFixProposal) => {
    setSkippedIds(prev => new Set(prev).add(fix.target_node_id))
  }

  const toggleExpanded = (id: string) => {
    setExpandedIds(prev => {
      const next = new Set(prev)
      if (next.has(id)) next.delete(id)
      else next.add(id)
      return next
    })
  }

  const pendingFixes = fixes.filter(
    f => !appliedIds.has(f.target_node_id) && !skippedIds.has(f.target_node_id)
  )
  const allHandled = pendingFixes.length === 0

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/80 backdrop-blur-sm p-4">
      <div className="relative flex h-[80vh] w-full max-w-2xl flex-col bg-card border border-border rounded-2xl shadow-lg">
        {/* Header */}
        <div className="flex items-center justify-between border-b border-border px-6 py-4">
          <div className="flex items-center gap-2">
            <Sparkles className="h-5 w-5 text-primary" />
            <h2 className="text-lg font-semibold text-foreground">
              AI Fix Proposals ({fixes.length})
            </h2>
          </div>
          <button
            onClick={onClose}
            className="rounded-md p-1 text-muted-foreground hover:bg-accent hover:text-foreground"
          >
            <X className="h-5 w-5" />
          </button>
        </div>

        {/* Body */}
        <div className="flex-1 overflow-y-auto p-4 space-y-3">
          {fixes.map((fix) => {
            const isApplied = appliedIds.has(fix.target_node_id)
            const isSkipped = skippedIds.has(fix.target_node_id)
            const isExpanded = expandedIds.has(fix.target_node_id)

            return (
              <div
                key={fix.target_node_id}
                className={cn(
                  'rounded-lg border p-4',
                  isApplied
                    ? 'border-emerald-400/30 bg-emerald-400/5'
                    : isSkipped
                      ? 'border-border bg-accent/30 opacity-60'
                      : 'border-border bg-card'
                )}
              >
                {/* Fix header */}
                <div className="flex items-start justify-between gap-3">
                  <div className="flex-1">
                    <p className="text-sm text-red-400 mb-1">{fix.error_message}</p>
                    <p className="text-sm text-foreground">{fix.description}</p>
                    <p className="text-xs text-muted-foreground mt-1">
                      Node: {fix.target_node_id}
                    </p>
                  </div>
                  {isApplied && (
                    <span className="flex items-center gap-1 rounded-full bg-emerald-400/10 px-2 py-1 text-xs text-emerald-400">
                      <Check className="h-3 w-3" /> Applied
                    </span>
                  )}
                  {isSkipped && (
                    <span className="text-xs text-muted-foreground">Skipped</span>
                  )}
                </div>

                {/* Expand/collapse detail */}
                {!isApplied && !isSkipped && (
                  <>
                    <button
                      onClick={() => toggleExpanded(fix.target_node_id)}
                      className="mt-2 flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground"
                    >
                      {isExpanded ? <ChevronUp className="h-3 w-3" /> : <ChevronDown className="h-3 w-3" />}
                      {isExpanded ? 'Hide' : 'Show'} details
                    </button>

                    {isExpanded && (
                      <div className="mt-3 grid grid-cols-2 gap-3">
                        <div>
                          <p className="text-xs font-medium text-muted-foreground mb-1">Before</p>
                          <pre className="overflow-x-auto rounded bg-accent/50 p-2 text-xs text-muted-foreground max-h-48 overflow-y-auto">
                            {JSON.stringify(fix.original_node, null, 2)}
                          </pre>
                        </div>
                        <div>
                          <p className="text-xs font-medium text-emerald-400 mb-1">After</p>
                          <pre className="overflow-x-auto rounded bg-emerald-400/5 p-2 text-xs text-foreground max-h-48 overflow-y-auto">
                            {JSON.stringify(fix.fixed_node, null, 2)}
                          </pre>
                        </div>
                      </div>
                    )}

                    {/* Action buttons */}
                    <div className="mt-3 flex gap-2">
                      <button
                        onClick={() => handleApply(fix)}
                        className="flex items-center gap-1 rounded-md bg-gradient-brand px-3 py-1.5 text-xs font-medium text-white shadow-sm shadow-primary/20 hover:opacity-90"
                      >
                        <Check className="h-3 w-3" />
                        Apply
                      </button>
                      <button
                        onClick={() => handleSkip(fix)}
                        className="flex items-center gap-1 rounded-md border border-border px-3 py-1.5 text-xs font-medium text-muted-foreground hover:bg-accent hover:text-foreground"
                      >
                        <SkipForward className="h-3 w-3" />
                        Skip
                      </button>
                    </div>
                  </>
                )}
              </div>
            )
          })}
        </div>

        {/* Footer */}
        <div className="flex items-center justify-between border-t border-border px-6 py-4">
          <button
            onClick={onClose}
            className="rounded-md border border-border px-4 py-2 text-sm font-medium text-muted-foreground hover:bg-accent hover:text-foreground"
          >
            {allHandled ? 'Done' : 'Cancel'}
          </button>
          {!allHandled && (
            <button
              onClick={onApplyAll}
              className="rounded-md bg-gradient-brand px-4 py-2 text-sm font-medium text-white shadow-lg shadow-primary/20 hover:opacity-90"
            >
              Apply All ({pendingFixes.length})
            </button>
          )}
        </div>
      </div>
    </div>
  )
}
```

**Step 2: Build to verify**

Run: `cd frontend && npm run build`
Expected: Build passes.

**Step 3: Commit**

```bash
git add frontend/src/components/tree-editor/AIFixReviewModal.tsx
git commit -m "feat: add AIFixReviewModal component for reviewing AI-proposed fixes"
```

---

## Task 11: Wire everything together in TreeEditorPage

**Files:**
- Modify: `frontend/src/pages/TreeEditorPage.tsx`

This is the integration task. The page needs to:

1. Import the new components and API
2. Add state for fix flow (`isFixing`, `fixProposals`)
3. Handle "Fix with AI" button click — call `treesApi.fixTree()`
4. Show `AIFixReviewModal` when proposals are available
5. Handle apply/skip — call `updateNode()` on the tree editor store
6. Re-run `validate()` after applying fixes

**Step 1: Find where ValidationSummary is rendered in TreeEditorPage**

Search for `<ValidationSummary` in `TreeEditorPage.tsx` and note the exact location.

**Step 2: Add imports**

Add to the imports in `TreeEditorPage.tsx`:

```typescript
import { AIFixReviewModal } from '@/components/tree-editor/AIFixReviewModal'
import { treesApi } from '@/api/trees'
import type { AIFixProposal } from '@/types'
```

**Step 3: Add state**

Inside the `TreeEditorPage` component, add:

```typescript
const [isFixing, setIsFixing] = useState(false)
const [fixProposals, setFixProposals] = useState<AIFixProposal[] | null>(null)
```

**Step 4: Add handler for "Fix with AI"**

```typescript
const handleFixWithAI = async () => {
  const store = useTreeEditorStore.getState()
  if (!store.treeStructure) return

  // Get only fixable errors (structural errors with nodeId)
  const fixableErrors = store.validationErrors
    .filter(e => e.severity === 'error' && e.nodeId)
    .map(e => ({ node_id: e.nodeId!, message: e.message }))

  if (fixableErrors.length === 0) return

  setIsFixing(true)
  try {
    const result = await treesApi.fixTree({
      tree_structure: store.treeStructure as Record<string, unknown>,
      tree_name: store.name,
      tree_type: (store.treeType || 'troubleshooting') as 'troubleshooting' | 'procedural' | 'maintenance',
      validation_errors: fixableErrors,
    })
    if (result.fixes.length > 0) {
      setFixProposals(result.fixes)
    } else {
      toast.info('AI could not generate fixes for these errors')
    }
  } catch {
    toast.error('Failed to generate AI fixes. Please try again.')
  } finally {
    setIsFixing(false)
  }
}
```

**Step 5: Add handlers for apply/close**

```typescript
const handleApplyFix = (fix: AIFixProposal) => {
  const store = useTreeEditorStore.getState()
  store.updateNode(fix.target_node_id, fix.fixed_node as Partial<TreeStructure>)
}

const handleApplyAllFixes = () => {
  if (!fixProposals) return
  for (const fix of fixProposals) {
    handleApplyFix(fix)
  }
  setFixProposals(null)
  // Re-validate after applying all fixes
  setTimeout(() => {
    useTreeEditorStore.getState().validate()
  }, 100)
}

const handleCloseFixModal = () => {
  setFixProposals(null)
  // Re-validate in case some fixes were applied
  useTreeEditorStore.getState().validate()
}
```

**Step 6: Pass props to ValidationSummary**

Update the `<ValidationSummary>` JSX to include the new props:

```tsx
<ValidationSummary
  errors={validationErrors}
  onSelectNode={handleSelectNode}
  onFixWithAI={handleFixWithAI}
  isFixing={isFixing}
/>
```

**Step 7: Add the review modal**

After `<ValidationSummary>`, add:

```tsx
{fixProposals && (
  <AIFixReviewModal
    fixes={fixProposals}
    onApply={handleApplyFix}
    onApplyAll={handleApplyAllFixes}
    onClose={handleCloseFixModal}
  />
)}
```

**Step 8: Build to verify**

Run: `cd frontend && npm run build`
Expected: Build passes.

**Step 9: Commit**

```bash
git add frontend/src/pages/TreeEditorPage.tsx
git commit -m "feat: wire AI fix flow into TreeEditorPage"
```

---

## Task 12: Final verification

**Step 1: Run all backend tests**

Run: `cd backend && python -m pytest --override-ini="addopts=" -v`
Expected: All pass.

**Step 2: Run frontend build**

Run: `cd frontend && npm run build`
Expected: Build passes with no errors.

**Step 3: Final commit if any adjustments needed**

Fix any issues found during verification and commit.
