# AGENT.md & GEMINI.md Rule Template

To ensure that any AI assistant working on the project strictly adheres to the database design process and never modifies the database without updating the MCD/MLD, add the following section to the project's root `AGENT.md` or `GEMINI.md` file (or `.agents/rules/db-modeling.md`).

---

## Copy-Paste Section for `AGENT.md` / `GEMINI.md`

```markdown
<!-- ===================================================================== -->
<!-- DATABASE DESIGN & MODIFICATION POLICY                                 -->
<!-- ===================================================================== -->

## Database Design & Modification Rules (MANDATORY)

> [!IMPORTANT]
> **YOU CANNOT PERFORM ANY DATABASE MODIFICATIONS WITHOUT USING THE `mcd-mld-designer` SKILL.**
> 
> Direct editing of database tables, columns, migrations, or ORM models without first updating the documentation is strictly forbidden.

### 1. Source of Truth Files
All database models are tracked and versioned in the following project files:
- `db/mcd.md`: Conceptual Data Model (MCD) containing the Data Dictionary, Entities, Associations, and Mermaid Flowchart.
- `db/mld.md`: Logical Data Model (MLD) containing Relational Schemas, Constraints, and Mermaid ER Diagram.

### 2. Pre-Modification Protocol
Before creating a new table, adding/renaming a column, or altering a relationship:
1. Activate the `mcd-mld-designer` skill.
2. Read and analyze the current state in `db/mcd.md` and `db/mld.md`.
3. Update `db/mcd.md` (Entities, Attributes, Associations, Cardinalities).
4. Update `db/mld.md` (Relational Schemas, Foreign Keys, Types, Constraints).
5. Document the modification in the Changelog section of both files.
6. Only after steps 1-5 are completed may code, ORM models, or migration scripts be written.

### 3. Strict Naming Conventions
- **Tables**: `<3_CHARS_DB>_<TABLE_NAME>` in UPPERCASE (e.g. `ECO_CUSTOMER`).
- **Columns**: `<3_CHARS_TABLE>_<COLUMN_NAME>` in UPPERCASE (e.g. `CUS_EMAIL`, `CUS_ID`).
- **Foreign Keys**: `<HOST_TRIGRAM>_<TARGET_TRIGRAM>_<COLUMN_NAME>` (e.g. in `ECO_ORDER`, FK referencing `ECO_CUSTOMER` is `ORD_CUS_ID`).
- **Associative Tables**: Meaningful functional name (e.g. `ECO_ORDER_ITEM` with `ITE_ORD_ID`, `ITE_PRO_ID`, `ITE_QUANTITY`) or concatenated entity names.
- **Casing**: UPPERCASE for all prefixes, table names, column names, and data types.
```

---

## Alternative: Local Rule File (`.agents/rules/db-modeling.md`)

If the project uses Antigravity directory-based rules, create `.agents/rules/db-modeling.md` with frontmatter:

```markdown
---
description: Mandatory database design and modification rules using mcd-mld-designer
trigger: always_on
---

# Database Modification Enforcement Rule

Whenever the user's prompt or task involves database tables, schema design, migrations, or ORM models:
1. Activate and follow the `mcd-mld-designer` skill.
2. Ensure all schema definitions exist and are maintained in `db/mcd.md` and `db/mld.md`.
3. Respect all naming conventions (<DB>_<TABLE> and <TBL>_<COL>) and UPPERCASE casing.
```