afv-library/skills/generating-custom-object/SKILL.md

---
name: generating-custom-object
description: "Use this skill when users need to create, generate, or validate Salesforce Custom Object metadata. Trigger when users mention custom objects, creating objects, object metadata, .object files, sharing models, name fields, or validation rules on objects. Also use when users say things like \"create a custom object\", \"generate object metadata\", \"set up an object for...\", or when they're troubleshooting object deployment errors especially around sharing models and Master-Detail relationships. Always use this skill for any custom object metadata work."
metadata:
  version: "1.0"
---

## When to Use This Skill

Use this skill when you need to:
- Create new custom objects
- Generate custom object metadata XML
- Configure object sharing and security settings
- Set up object features and capabilities
- Troubleshoot deployment errors related to custom objects

## Specification

## 1. Overview and Purpose

This document defines the mandatory constraints for generating CustomObject metadata XML (`.object-meta.xml` file). The agent must verify these constraints before outputting XML to prevent Metadata API deployment errors.

**File extension:** `.object-meta.xml`

---

## 2. Syntactic Essentials (Tier 1)

The following constraints must be true for the XML body to deploy successfully.

**Note:** The API Name (fullName) is NOT a tag; it is the filename (e.g., `Vehicle__c.object-meta.xml`).

### Required Elements

| Element | Requirement | Notes |
|---------|-------------|-------|
| `<label>` | Required | Singular UI name |
| `<pluralLabel>` | Required | Plural UI name |
| `<sharingModel>` | Required | See Sharing Model Rules below |
| `<deploymentStatus>` | Required | Always set to `Deployed` |
| `<nameField>` | Required | Primary record identifier (requires `<label>` and `<type>`) |
| `<visibility>` | Required | Always set to `Public` |

### Sharing Model Rules

**Default:** Set `<sharingModel>` to `ReadWrite`.

**Exception:** If this object contains a Master-Detail relationship field, `<sharingModel>` MUST be `ControlledByParent`.

**Decision Logic:**
- IF object has NO Master-Detail field → use `ReadWrite`
- IF object has Master-Detail field → use `ControlledByParent`
- IF a Master-Detail field is being added to an existing child object → that existing object's `<sharingModel>` must also be updated to `ControlledByParent`

**❌ INCORRECT** — Will cause error: `Cannot set sharingModel to ReadWrite on a CustomObject with a MasterDetail relationship field`
```xml
<CustomObject xmlns="http://soap.sforce.com/2006/04/metadata">
  <label>Order Line Item</label>
  <pluralLabel>Order Line Items</pluralLabel>
  <sharingModel>ReadWrite</sharingModel>  <!-- WRONG: Object has a M-D field -->
  <deploymentStatus>Deployed</deploymentStatus>
</CustomObject>
```

**✅ CORRECT:**
```xml
<CustomObject xmlns="http://soap.sforce.com/2006/04/metadata">
  <label>Order Line Item</label>
  <pluralLabel>Order Line Items</pluralLabel>
  <sharingModel>ControlledByParent</sharingModel>  <!-- CORRECT -->
  <deploymentStatus>Deployed</deploymentStatus>
</CustomObject>
```

---

## 3. Smart Defaults & Decision Logic (Tier 2)

The agent must choose which features to enable based on the object's intended use case.

### A. The Name Field Decision

| Type | When to Use | Additional Requirements |
|------|-------------|------------------------|
| **Text** | Default for human-named entities (Projects, Locations, Teams) | None |
| **AutoNumber** | Use for transactions, logs, or IDs (Invoices, Requests, Tickets) | Must include `<displayFormat>` (e.g., `INV-{0000}`) and `<startingNumber>1</startingNumber>` |

**Text Name Field Example:**
```xml
<nameField>
  <label>Project Name</label>
  <type>Text</type>
</nameField>
```

**AutoNumber Name Field Example:**
```xml
<nameField>
  <label>Invoice Number</label>
  <type>AutoNumber</type>
  <displayFormat>INV-{0000}</displayFormat>
  <startingNumber>1</startingNumber>
</nameField>
```

### B. Object Description

**`<description>`**: Mandatory. Every object must contain a professional summary.

If the intent is vague, generate a summary:
> "Object used to track and manage [Intent] within the organization."
### C. Junction Object Naming

If the object is a many-to-many link between two parents, name the object by combining the two parent entities to ensure the schema remains intuitive.

**Examples:**
- `Position_Candidate__c` (links Position and Candidate)
- `Job_Application__c` (links Job and Application)

### D. Feature Enablement (Clean XML)

To maintain "Clean XML," only include optional tags when deviating from the Salesforce platform default of `false`.

**Scenario A: User-Facing Objects (Apps, Trackers, Business Entities)**
- Trigger: The object is intended for direct user interaction
- Action: Set `<enableSearch>`, `<enableReports>`, `<enableActivities>`, and `<enableHistory>` to `true`

**Scenario B: System-Facing Objects (Junctions, Background Logs)**
- Trigger: The object exists for technical associations or background data
- Action: Omit these tags to keep the UI clean and the XML lean

---

## 4. Critical Constraints & Common Failures

### Reserved Words

Never use reserved words as API names for Custom Objects or Custom Fields:

| Category | Reserved Words (Do Not Use as API Names) |
|----------|------------------------------------------|
| SOQL/SQL | `Select`, `From`, `Where`, `Limit`, `Order`, `Group` |
| System | `User`, `External`, `View`, `Type` |
| Temporal | `Date`, `Number` |

### Relationship Cap

Do not create more than **2 Master-Detail relationships** for a single object. If a third relationship is required, use a Lookup instead.

### XML Root Element

Do NOT include the `<fullName>` tag at the root of the `.object-meta.xml` file. The API name is derived from the filename.

**❌ INCORRECT:**
```xml
<CustomObject xmlns="http://soap.sforce.com/2006/04/metadata">
  <fullName>Vehicle__c</fullName>  <!-- WRONG: Remove this -->
  <label>Vehicle</label>
</CustomObject>
```

**✅ CORRECT:**
```xml
<CustomObject xmlns="http://soap.sforce.com/2006/04/metadata">
  <label>Vehicle</label>
  <!-- fullName comes from filename: Vehicle__c.object-meta.xml -->
</CustomObject>
```

### Validation Rule Naming Convention

Validation rule names follow different conventions than custom fields.

**Rules:**
- Must contain only alphanumeric characters and underscores
- Must begin with a letter
- Cannot end with an underscore
- Cannot contain two consecutive underscores
- **Must NOT end with `__c`** (unlike custom fields)

**❌ INCORRECT:**
```xml
<validationRules>
  <fullName>Require_Start_Date__c</fullName>  <!-- WRONG: Has __c suffix -->
  <active>true</active>
  <errorMessage>Start Date is required.</errorMessage>
  <formula>ISBLANK(Start_Date__c)</formula>
</validationRules>
```
**Error:** `The validation name can only contain alphanumeric characters, must begin with a letter, cannot end with an underscore...`

**✅ CORRECT:**
```xml
<validationRules>
  <fullName>Require_Start_Date</fullName>  <!-- CORRECT: No __c suffix -->
  <active>true</active>
  <errorMessage>Start Date is required.</errorMessage>
  <formula>ISBLANK(Start_Date__c)</formula>
</validationRules>
```

**Naming Pattern Reference:**

| Metadata Type | Naming Pattern | Example |
|---------------|----------------|---------|
| Custom Fields | Ends with `__c` | `Start_Date__c` |
| Validation Rules | No suffix | `Require_Start_Date` |
| Custom Objects | Ends with `__c` | `Vehicle__c` |

---

## 5. Verification Checklist

Before generating the Custom Object XML, verify:

### Syntactic Checks
- [ ] Are both `<label>` and `<pluralLabel>` present?
- [ ] Is `<deploymentStatus>` set to `Deployed`?
- [ ] Is `<visibility>` set to `Public`?
- [ ] Does `<nameField>` include both `<label>` and `<type>`?
- [ ] If `<type>` is `AutoNumber`, are `<displayFormat>` and `<startingNumber>` included?

### Sharing Model Check (Critical)
- [ ] Does this object have a Master-Detail relationship field?
    - If YES → `<sharingModel>` MUST be `ControlledByParent`
    - If NO → `<sharingModel>` should be `ReadWrite`

### Constraint Checks
- [ ] Is the API name free of reserved words?
- [ ] Are there 2 or fewer Master-Detail relationships?
- [ ] Is `<fullName>` absent from the XML root?

### Validation Rule Checks (if applicable)
- [ ] Do validation rule names NOT end with `__c`?
- [ ] Do validation rule names follow alphanumeric + underscore pattern?

### Architectural Checks
- [ ] Is `<description>` present with a meaningful summary?
- [ ] Are `<enableSearch>` and `<enableReports>` set to `true` if user-facing?
- [ ] Does the filename match the intended API name?