Frontmatter MCP

# 10. Store embedding cache under base directory Date: 2025-12-05 ## Status Accepted ## Context Semantic search requires persistent storage for embedding vectors to avoid regenerating them on every startup. Options considered for cache location: | Option | Example Path | Pros | Cons | |--------|--------------|------|------| | XDG cache | `~/.cache/frontmatter-mcp/` | Standard on Linux | Platform-specific paths needed | | platformdirs | Varies by OS | Cross-platform | Additional dependency | | Base directory | `{base_dir}/.frontmatter-mcp/` | Simple, portable | Stored with user data | Platform-specific cache paths: - Linux: `~/.cache/` - macOS: `~/Library/Caches/` - Windows: `AppData/Local/` ## Decision Store embedding cache under the base directory: `{FRONTMATTER_BASE_DIR}/.frontmatter-mcp/embeddings.duckdb` Override is available via `FRONTMATTER_CACHE_DIR` environment variable. ## Consequences Benefits: - Cache is isolated per vault/project (each base directory gets its own cache) - No platform-specific logic needed - Cache travels with the data when moving directories - No additional dependencies (no platformdirs) Trade-offs: - Hidden directory (`.frontmatter-mcp/`) is stored alongside user content - Backup tools may include cache files unless excluded - Cache is not shared between different base directories (intentional)