Now I have all the context needed to write the section. Let me also quickly look at the `_CATEGORY_MAP` keys more carefully and the `PurePosixPath` usage for extracting directories, since the suggestion logic needs to collect directories with recognized asset extensions.

I have all the information needed. Let me produce the section content.

# Section 7: ASSET_REGISTRY -- Fuzzy Match Suggestions

## Overview

When a user calls `godotiq_asset_registry` with a `path_filter` that matches zero assets, the response currently returns empty results with no guidance. This section adds a `suggestions` key containing a sorted list of directories that actually contain recognized asset files, helping the user correct their filter.

The change is entirely Python-side, within `src/godotiq/tools/assets/__init__.py`. It modifies the `_build_asset_registry` function only on the zero-result code path, so there is no performance impact for normal queries.

## File to Modify

- `/Users/salvatorefarruggio/Desktop/godotiq/src/godotiq/tools/assets/__init__.py` -- the `_build_asset_registry` function

## Tests to Add

All tests go in the existing file `/Users/salvatorefarruggio/Desktop/godotiq/tests/test_tools/test_asset_registry.py`.

```python
# --- New test classes to add at the end of test_asset_registry.py ---

class TestAssetRegistrySuggestionsOnEmpty:
    """When path_filter produces 0 matches, suggestions list returned."""

    def test_zero_matches_returns_suggestions(self, session: GodotIQSession) -> None:
        """path_filter with 0 matches -> suggestions list with valid directories."""
        # Use a filter that won't match anything in the sample project
        result = _build_asset_registry(session, path_filter="nonexistent_folder_xyz")
        assert result["total_assets"] == 0
        assert "suggestions" in result
        assert isinstance(result["suggestions"], list)
        # The sample project has assets under res://assets/models/printers/
        # so at least one suggestion should exist
        assert len(result["suggestions"]) >= 1

    def test_suggestions_contain_only_asset_directories(self, session: GodotIQSession) -> None:
        """Suggestions contain only directories with recognized asset files."""
        result = _build_asset_registry(session, path_filter="nonexistent_folder_xyz")
        assert "suggestions" in result
        # Each suggestion should be a res:// directory path string
        for s in result["suggestions"]:
            assert isinstance(s, str)
            assert s.startswith("res://")

    def test_suggestions_sorted_alphabetically(self, session: GodotIQSession) -> None:
        """Suggestions are sorted alphabetically."""
        result = _build_asset_registry(session, path_filter="nonexistent_folder_xyz")
        assert "suggestions" in result
        assert result["suggestions"] == sorted(result["suggestions"])

    def test_suggestions_capped_at_20(self, session: GodotIQSession) -> None:
        """Suggestions list capped at 20 entries."""
        # Inject many fake asset directories into the index to exceed the cap
        original_assets = dict(session._index.assets)
        try:
            for i in range(25):
                fake_path = f"res://fake_dir_{i:02d}/model.glb"
                session._index.assets[fake_path] = {"type": "model", "size_bytes": 10}
            result = _build_asset_registry(session, path_filter="nonexistent_folder_xyz")
            assert "suggestions" in result
            assert len(result["suggestions"]) <= 20
        finally:
            session._index.assets = original_assets


class TestAssetRegistryNoSuggestionsWhenMatches:
    """When path_filter has matches, no suggestions key."""

    def test_matches_no_suggestions(self, session: GodotIQSession) -> None:
        """path_filter with matches -> no suggestions key in result."""
        # "printers" matches assets in the sample project
        result = _build_asset_registry(session, path_filter="printers")
        assert result["total_assets"] > 0
        assert "suggestions" not in result


class TestAssetRegistrySuggestionsEmptyProject:
    """Empty project yields empty suggestions list."""

    def test_empty_project_empty_suggestions(self, session: GodotIQSession) -> None:
        """Empty project -> empty suggestions list."""
        original_assets = dict(session._index.assets)
        try:
            session._index.assets = {}
            result = _build_asset_registry(session, path_filter="anything")
            assert result["total_assets"] == 0
            assert "suggestions" in result
            assert result["suggestions"] == []
        finally:
            session._index.assets = original_assets
```

The tests import `_build_asset_registry` and `GodotIQSession` which are already imported at the top of the existing test file. The `session` fixture comes from `tests/test_tools/conftest.py` and loads the sample project at `tests/fixtures/sample_project/`.

## Implementation Details

The logic is added inside `_build_asset_registry` in `/Users/salvatorefarruggio/Desktop/godotiq/src/godotiq/tools/assets/__init__.py`. The change happens **after** the main iteration loop has built `assets_list`, and **before** the detail-level branching that builds the result dict.

### Where to Insert

After the `max_results` cap (around line 173 in the current file, after `assets_list = assets_list[:max_results]`), and before the `if detail == "brief":` branching block.

### Logic

1. Check if `path_filter` was provided AND `assets_list` is empty (zero results after filtering).
2. If so, scan ALL assets in `index.assets` (the unfiltered set) to collect unique parent directory paths.
3. Only include a directory if at least one asset file in it has an extension recognized by `_CATEGORY_MAP`.
4. Sort the directory list alphabetically.
5. Cap at 20 entries.
6. Store the result in a local variable (e.g., `suggestions`).

Then, in each of the three detail-level branches (`brief`, `normal`, `full`), add the `suggestions` key to the result dict when it is non-None.

### Pseudocode

```python
# After max_results cap, before detail branching:
suggestions = None
if path_filter and len(assets_list) == 0:
    # Collect directories containing recognized asset files
    asset_dirs: set[str] = set()
    for asset_path in index.assets:
        ext = PurePosixPath(asset_path).suffix.lower()
        if ext in _CATEGORY_MAP:
            parent = str(PurePosixPath(asset_path).parent)
            asset_dirs.add(parent)
    suggestions = sorted(asset_dirs)[:20]
```

Then inside each result-building branch, after setting `result["path_filter"]`:

```python
if suggestions is not None:
    result["suggestions"] = suggestions
```

### Key Design Decisions

- **`_CATEGORY_MAP` filtering**: Only directories containing files with recognized extensions (`.glb`, `.png`, `.tscn`, etc.) are suggested. Directories with only unknown file types (e.g., `.txt`, `.md`) are excluded. This uses the same `_CATEGORY_MAP` dict already defined at module level.

- **`PurePosixPath` for directory extraction**: The codebase already uses `PurePosixPath` for `res://` path manipulation (see line 157 of the current code: `directory = str(PurePosixPath(asset_path).parent)`). The suggestion logic follows the same pattern.

- **Cap at 20**: Prevents token bloat when a project has hundreds of directories. The sort ensures deterministic ordering.

- **Zero-result path only**: The `suggestions` variable remains `None` when there are matches, and the `suggestions` key is only added to the result dict when non-None. This means existing responses are completely unchanged -- no `suggestions` key appears when the filter has matches.

- **No `path_filter` means no suggestions**: If `path_filter` is empty/not provided, suggestions are never computed, even if the project has zero assets. Suggestions are specifically a "your filter didn't match anything, here's what exists" feature.

### Integration with `apply_output_limit`

The `suggestions` list contains short directory path strings (e.g., `"res://assets/models/printers"`), capped at 20 items. This is well within any output limit. If `apply_output_limit` is called with `list_keys`, the suggestions list should NOT be included in truncatable list keys since it is already capped and small. The existing `list_keys` arguments in the three branches (`"unused_list"`, `"assets"`) remain unchanged.

## Dependencies

None. This section is fully independent. It modifies only `_build_asset_registry` in `assets/__init__.py` and adds tests in the existing test file. No other sections touch this function or file.

---

## Implementation Results

### Files Modified
- `src/godotiq/tools/assets/__init__.py` — added suggestion logic after max_results cap, injected `suggestions` key in all three detail branches
- `tests/test_tools/test_asset_registry.py` — added 8 new tests (6 from plan + 2 from code review)

### Deviations from Plan
1. **`res://` normalization**: `PurePosixPath` collapses `res://` to `res:/` in `.parent`. Added post-processing to restore `res://` prefix in suggestions. Test assertion kept at `res://` (stricter than plan's fallback).
2. **Single PurePosixPath construction**: Code review optimization — construct `PurePosixPath` once per asset instead of twice.
3. **Extra tests**: Added `test_suggestions_in_brief_detail` and `test_suggestions_in_full_detail` per code review finding.

### Test Count
- 16 total tests in test_asset_registry.py (8 existing + 8 new)
- All passing