# Advanced Alchemy Services

> Implement Advanced Alchemy service layers for business logic, schema validation, data transformation, and coordinated repository operations using Pydantic, Msgspec, attrs, or plain dictionaries. Use when handlers need more than raw CRUD, when repository results must be converted to schemas, or when complex create and update flows span multiple models. Do not use for low-level model or repository definition alone.

- Skill: `alti3/advanced-alchemy-services` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add alti3/advanced-alchemy-services`
- Raw SKILL.md: https://api.skillmd.com/api/skills/alti3/advanced-alchemy-services/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: alti3 (https://skillmd.com/u/alti3)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/alti3/advanced-alchemy-services

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# Services

## Execution Workflow

1. Start from the repository and wrap it with `SQLAlchemyAsyncRepositoryService` or `SQLAlchemySyncRepositoryService`.
2. Define schema types for create, update, and read flows only where service boundaries need validation or conversion.
3. Set `repository_type`, loader options, and `match_fields` explicitly.
4. Override `create()`, `update()`, or `to_model()` only for real domain rules such as slug generation or multi-model coordination.
5. Convert outbound models with `to_schema()` instead of leaking ORM instances to transport layers.

## Implementation Rules

- Keep services responsible for business rules, not controller or router concerns.
- Accept dictionaries or schema objects, but normalize them consistently through the service.
- Use schema conversion intentionally: Pydantic, Msgspec, and attrs are all supported.
- Keep multi-repository workflows atomic and explicit about commit behavior.

## Example Pattern

```python
from advanced_alchemy.service import SQLAlchemyAsyncRepositoryService


class PostService(SQLAlchemyAsyncRepositoryService[Post, PostRepository]):
    repository_type = PostRepository
```

## Validation Checklist

- Confirm service input can be converted into models for both create and update paths.
- Confirm `to_schema()` returns the expected response shape for the chosen schema library.
- Confirm custom service overrides preserve repository invariants.
- Confirm complex operations load the relationships they depend on.

## Cross-Skill Handoffs

- Use `advanced-alchemy-repositories` for persistence operations beneath the service.
- Use `advanced-alchemy-routing` when mapping service methods onto CRUD endpoints.
- Use `advanced-alchemy-litestar`, `advanced-alchemy-fastapi`, or `advanced-alchemy-flask` for framework DI and request handling.

## Advanced Alchemy References

- https://advanced-alchemy.litestar.dev/latest/usage/services.html
- https://github.com/litestar-org/advanced-alchemy/blob/main/README.md