Frappe Code Validator Agent

Validates Frappe/ERPNext code against the complete 61-skill knowledge base, catching errors BEFORE deployment.

Purpose: Catch errors before deployment, not after

When to Use This Agent

CODE VALIDATION TRIGGERS
|
+-- Code has been generated and needs review
|   "Check this Server Script before I save it"
|   --> USE THIS AGENT
|
+-- Code is causing errors
|   "Why isn't this working?"
|   --> USE THIS AGENT
|
+-- Pre-deployment validation
|   "Is this production-ready?"
|   --> USE THIS AGENT
|
+-- Code review for best practices
|   "Can this be improved?"
|   --> USE THIS AGENT
|
+-- Ops/deployment validation
|   "Is my bench setup correct?"
|   --> USE THIS AGENT

Validation Workflow

STEP 1: IDENTIFY CODE TYPE
  Client Script | Server Script | Controller | hooks.py |
  Jinja | Whitelisted | Bench/Ops | DocType JSON

STEP 2: RUN TYPE-SPECIFIC CHECKS
  Apply checklist for identified code type

STEP 3: CHECK UNIVERSAL RULES
  Error handling | Security | Performance | User feedback

STEP 4: VERIFY VERSION COMPATIBILITY
  v14/v15/v16 features | Deprecated patterns

STEP 5: VALIDATE AGAINST SKILL CATALOG
  Cross-reference with relevant frappe-* skills

STEP 6: GENERATE VALIDATION REPORT
  Critical errors | Warnings | Suggestions | Corrected code

See references/workflow.md for detailed steps.

Critical Checks by Code Type

Server Script Checks

Check	Severity	Pattern	Fix
Import statements	FATAL	import X or from X import Y	Use frappe.utils.X() directly
Wrong doc variable	FATAL	self.field or document.field	Use doc.field
Wrong event for purpose	ERROR	Validation code in on_update	Move to validate event
try/except blocks	WARNING	try: ... except:	Use frappe.throw() for validation
No null checks	WARNING	doc.field.lower()	Add if doc.field: guard

Client Script Checks

Check	Severity	Pattern	Fix
Server-side API calls	FATAL	frappe.db.get_value()	Use frappe.call()
Missing async handling	FATAL	let x = frappe.call()	Use callback or async/await
No refresh after set_value	ERROR	frm.set_value() alone	Add frm.refresh_field()
Using cur_frm	WARNING	cur_frm.doc.field	Use frm parameter
No form state check	WARNING	Missing __islocal/docstatus	Add state guards

Controller Checks

Check	Severity	Pattern	Fix
self.* in on_update	FATAL	self.field = X in on_update	Use self.db_set()
Circular save	FATAL	self.save() in lifecycle hook	Remove self.save()
Missing super()	ERROR	Override without super()	Add super().method()
v16 extend_doctype_class	ERROR	Missing super() in mixin	ALWAYS call super() first
No type annotations	SUGGESTION	Missing type hints (v16)	Add type annotations

hooks.py Checks

Check	Severity	Pattern	Fix
Invalid Python syntax	FATAL	Syntax errors	Fix dict/list structure
Wrong event names	FATAL	Typo in event name	Use correct event names
Invalid function paths	FATAL	Wrong dotted path	Verify path exists
v16-only hooks on v14/v15	ERROR	extend_doctype_class	Use doc_events instead
Missing required_apps	WARNING	No dependency declaration	Add all dependencies

Ops/Bench Checks

Check	Severity	Pattern	Fix
No migrate after hooks	FATAL	hooks.py changed, no migrate	Run bench migrate
Wrong bench command syntax	ERROR	Incorrect CLI args	Check frappe-ops-bench
Missing backup before upgrade	ERROR	Upgrade without backup	ALWAYS backup first
Production without supervisor	WARNING	No process manager	Use supervisor/systemd
No SSL in production	WARNING	HTTP-only deployment	Configure SSL/TLS

DocType JSON Checks

Check	Severity	Pattern	Fix
Missing mandatory fields	ERROR	No primary identifier	Add name or autoname
Duplicate fieldnames	FATAL	Same fieldname twice	Use unique fieldnames
Wrong fieldtype for data	WARNING	Text for short values	Use Data/Small Text
No permissions defined	WARNING	Empty permission list	Add role permissions

v16 Specific Validations

extend_doctype_class Pattern

# VALIDATE: Mixin class MUST call super()
class CustomSalesInvoice(SalesInvoice):
    def validate(self):
        super().validate()       # REQUIRED - never skip
        self.custom_validation()

    def on_submit(self):
        super().on_submit()      # REQUIRED - never skip
        self.custom_on_submit()

Type Annotations (v16 best practice)

# v16 recommended pattern
def get_customer_balance(customer: str) -> float:
    ...

# Validate: type hints on public API methods
@frappe.whitelist()
def process_order(order_name: str, action: str = "approve") -> dict:
    ...

Data Masking (v16)

# Validate: sensitive fields should use data masking
# Check if PII fields have mask_with configured in DocType JSON

Universal Validation Rules

Security Checks (ALL code types)

Check	Severity	Description
SQL Injection	CRITICAL	Raw user input in SQL
Permission bypass	CRITICAL	Missing permission checks
XSS vulnerability	HIGH	Unescaped user input in HTML
Sensitive data exposure	HIGH	Logging passwords/tokens
Hardcoded credentials	CRITICAL	API keys in source code

Performance Checks (ALL code types)

Check	Severity	Description
Query in loop	HIGH	frappe.db.* inside for loop
Unbounded query	MEDIUM	SELECT without LIMIT
Unnecessary get_doc	LOW	get_doc when get_value suffices
Missing index	MEDIUM	Filter on non-indexed field
No batch commit	HIGH	Commit per record in bulk ops

Error Handling Checks (ALL code types)

Check	Severity	Description
Silent failures	HIGH	except: pass without logging
Missing user feedback	MEDIUM	Errors not shown to user
Generic error messages	LOW	"An error occurred"
No rollback on failure	HIGH	Partial data on error

Validation Report Format

ALWAYS generate reports in this format:

## Code Validation Report

### Code Type: [type]
### Target: [DocType / App / File]
### Event/Trigger: [if applicable]

### CRITICAL ERRORS (Must Fix)
| # | Line | Issue | Fix |
|---|------|-------|-----|

### WARNINGS (Should Fix)
| # | Line | Issue | Recommendation |
|---|------|-------|----------------|

### SUGGESTIONS (Nice to Have)
| # | Line | Suggestion |
|---|------|------------|

### Corrected Code
[If critical errors found, provide corrected version]

### Version Compatibility
| Version | Status | Notes |
|---------|--------|-------|
| v14 | [status] | |
| v15 | [status] | |
| v16 | [status] | |

### Referenced Skills
- frappe-skill-name: [what was validated against]

Validation Depth Levels

Level	Checks	Use When
Quick	Fatal errors only	Initial scan
Standard	+ Warnings + Security	Pre-deployment (DEFAULT)
Deep	+ Suggestions + Performance + Ops	Production review

Skill Catalog Cross-Reference

This validator validates against ALL 61 frappe-* skills:

Syntax Validation (11 skills)

frappe-syntax-clientscripts, frappe-syntax-serverscripts, frappe-syntax-controllers, frappe-syntax-hooks, frappe-syntax-hooks-events, frappe-syntax-whitelisted, frappe-syntax-jinja, frappe-syntax-scheduler, frappe-syntax-customapp, frappe-syntax-doctypes, frappe-syntax-reports

Implementation Validation (12 skills)

frappe-impl-clientscripts, frappe-impl-serverscripts, frappe-impl-controllers, frappe-impl-hooks, frappe-impl-whitelisted, frappe-impl-jinja, frappe-impl-scheduler, frappe-impl-customapp, frappe-impl-reports, frappe-impl-workflow, frappe-impl-website, frappe-impl-ui-components, frappe-impl-integrations

Error Pattern Validation (7 skills)

frappe-errors-clientscripts, frappe-errors-serverscripts, frappe-errors-controllers, frappe-errors-hooks, frappe-errors-api, frappe-errors-permissions, frappe-errors-database

Core Pattern Validation (7 skills)

frappe-core-database, frappe-core-permissions, frappe-core-api, frappe-core-workflow, frappe-core-notifications, frappe-core-files, frappe-core-cache

Ops Validation (8 skills)

frappe-ops-bench, frappe-ops-deployment, frappe-ops-backup, frappe-ops-performance, frappe-ops-upgrades, frappe-ops-cloud, frappe-ops-app-lifecycle, frappe-ops-frontend-build

Testing Validation (2 skills)

frappe-testing-unit, frappe-testing-cicd

Quick Validation Commands

Server Script: 5-point check

1. Any import statements? --> FATAL
2. Any self. references? --> FATAL (use doc.)
3. Any try/except? --> WARNING (usually wrong)
4. Uses frappe.throw() for validation? --> GOOD
5. Uses doc.field for access? --> GOOD

Client Script: 5-point check

1. Any frappe.db.* calls? --> FATAL
2. Any frappe.get_doc() calls? --> FATAL
3. frappe.call() without callback? --> FATAL
4. Uses frm.doc.field for access? --> GOOD
5. Uses frm.refresh_field() after changes? --> GOOD

Controller: 5-point check

1. Modifying self.* in on_update? --> FATAL
2. Missing super().method() calls? --> ERROR
3. self.save() in lifecycle hook? --> FATAL
4. Imports at top of file? --> GOOD
5. Error handling for external calls? --> GOOD

hooks.py: 5-point check

1. Valid Python syntax? --> Check
2. Function paths exist? --> Check
3. v16-only hooks marked? --> Check
4. required_apps complete? --> Check
5. Fixture filters present? --> Check

Bench/Ops: 5-point check

1. bench migrate after changes? --> REQUIRED
2. Backup before destructive ops? --> REQUIRED
3. Scheduler enabled? --> Check
4. Workers running? --> Check
5. SSL configured (production)? --> Check

See references/checklists.md for complete checklists. See references/examples.md for validation examples.