> Use when writing Python code for ERPNext/Frappe Server Scripts including Document Events, API endpoints, Scheduler Events, and Permission Queries. (sandbox blocks ALL imports). Covers frappe.* methods, event name mapping, sandbox, import, doc event, validate, on_submit, before_save, server script example, import not allowed, sandbox rules, which script type to use.
npx skills add https://github.com/Impertio-Studio/Frappe_Claude_Skill_Package --skill frappe-syntax-serverscripts
Server Scripts are Python scripts managed via Setup > Server Script in the
Frappe/ERPNext UI. They run inside a RestrictedPython sandbox.
┌──────────────────────────────────────────────────────────────────┐
│ ALL import STATEMENTS ARE BLOCKED │
│ │
│ import json → ImportError: __import__ not found │
│ from datetime import * → ImportError: __import__ not found │
│ import frappe → ImportError (even frappe itself!) │
│ │
│ EVERYTHING you need is pre-loaded in the frappe namespace. │
│ NEVER write an import line. ALWAYS use frappe.utils.*, etc. │
└──────────────────────────────────────────────────────────────────┘
ALWAYS use the pre-loaded namespace instead of imports:
| Blocked import | Use instead |
|---|---|
| import json | frappe.parse_json() / frappe.as_json() |
| from datetime import date | frappe.utils.today() / frappe.utils.now_datetime() |
| from frappe.utils import cint | frappe.utils.cint() (already loaded) |
| import requests | frappe.make_get_request() / frappe.make_post_request() |
| import re | Not available — restructure logic without regex |
| import os / import sys | Not available — use a custom app instead |
# v14: enabled by default
# v15+: DISABLED by default — you MUST enable explicitly:
bench set-config -g server_script_enabled 1
# Or set server_script_enabled: true in site_config.json
NEVER expect Server Scripts to work on Frappe Cloud shared benches — they
require a private bench.
| Type | Trigger | Key Variable |
|---|---|---|
| Document Event | Document lifecycle (save, submit, cancel) | doc |
| API | HTTP request to /api/method/{name} | frappe.form_dict |
| Scheduler Event | Cron schedule | (none) |
| Permission Query | Document list filtering | user, conditions |
CRITICAL: The UI names differ from internal hook names:
| Server Script UI | Internal Hook | Fires When |
|---|---|---|
| Before Insert | before_insert | Before new doc saved to DB |
| After Insert | after_insert | After first DB insert |
| Before Validate | before_validate | Before framework validation |
| Before Save | validate | Before save (new + update) |
| After Save | on_update | After successful save |
| Before Submit | before_submit | Before submit (docstatus 0→1) |
| After Submit | on_submit | After submit completes |
| Before Cancel | before_cancel | Before cancel (docstatus 1→2) |
| After Cancel | on_cancel | After cancel completes |
| Before Delete | on_trash | Before permanent delete |
| After Delete | after_delete | After permanent delete |
NEVER confuse "Before Save" with before_save — the UI label "Before Save"
maps to the validate hook. The actual before_save hook runs AFTER validate.
Need custom Python logic for a DocType?
│
├─► Can you install a custom Frappe app?
│ ├─► YES: Use a Document Controller when you need:
│ │ • import statements (any Python library)
│ │ • File system access
│ │ • Complex class inheritance
│ │ • autoname / before_naming hooks
│ │ • Unit-testable code
│ │
│ └─► NO: Use a Server Script when:
│ • You only have UI access (no bench CLI)
│ • Logic is simple validation / field calculation
│ • You need a quick API endpoint
│ • You need dynamic permission filtering
│
└─► Is logic > 50 lines or needs external libraries?
├─► YES → Document Controller in a custom app
└─► NO → Server Script is fine
doc # Current document (Document Event only)
frappe # Core namespace — ALWAYS available
frappe.db # Database operations
frappe.utils # Date, number, string utilities
frappe.session # Current session (user, csrf_token)
frappe.form_dict # Request parameters (API scripts)
frappe.response # Response object (API scripts)
frappe.request # Werkzeug request object
frappe.qb # Query Builder (v14+)
json # Python json module (pre-loaded)
# Documents
frappe.get_doc(doctype, name) # Fetch document
frappe.new_doc(doctype) # Create new document
frappe.get_cached_doc(doctype, name) # Cached fetch (read-only)
frappe.get_last_doc(doctype) # Most recent document
frappe.get_mapped_doc(...) # Map fields between DocTypes
frappe.delete_doc(doctype, name) # Delete document
frappe.rename_doc(doctype, old, new) # Rename document
# Querying
frappe.get_all(doctype, filters, fields, order_by, limit) # No permission check
frappe.get_list(doctype, filters, fields, order_by, limit) # With permission check
frappe.db.get_value(doctype, name, fieldname)
frappe.db.get_single_value(doctype, fieldname)
frappe.db.set_value(doctype, name, fieldname, value)
frappe.db.exists(doctype, name_or_filters)
frappe.db.count(doctype, filters)
frappe.db.sql(query, values, as_dict) # ALWAYS parameterize!
frappe.db.escape(value) # SQL escape
frappe.db.commit() # ONLY in Scheduler scripts
frappe.db.rollback() # ONLY in Scheduler scripts
# Messaging
frappe.throw(msg, exc, title) # Stop execution + show error
frappe.msgprint(msg, title, indicator) # User notification
frappe.log_error(message, title) # Error Log entry
# HTTP (yes, these work in sandbox!)
frappe.make_get_request(url, params, headers)
frappe.make_post_request(url, data, headers)
frappe.make_put_request(url, data, headers)
# Email
frappe.sendmail(recipients, sender, subject, message)
# Utilities
frappe.utils.today() # "2024-01-15"
frappe.utils.now() # "2024-01-15 10:30:00"
frappe.utils.now_datetime() # datetime object
frappe.utils.add_days(date, n) # Date arithmetic
frappe.utils.add_months(date, n)
frappe.utils.date_diff(d1, d2) # Days between dates
frappe.utils.flt(val) # Safe float (None → 0.0)
frappe.utils.cint(val) # Safe int (None → 0)
frappe.utils.cstr(val) # Safe string (None → "")
frappe.parse_json(string) # JSON string → dict/list
frappe.as_json(obj) # dict/list → JSON string
frappe.render_template(template, ctx) # Jinja rendering
frappe.get_url() # Site URL
frappe.get_hooks(hook) # Read app hooks
run_script(script_name, **kwargs) # Call another Server Script
# Session / Permissions
frappe.session.user # Current user email
frappe.get_roles(user) # User's roles list
frappe.has_permission(doctype, ptype, doc)
frappe.get_fullname(user) # User's display name
_("translatable string") # Translation function
str, int, float, bool, list, dict, tuple, set # Types
range, enumerate, zip, map, filter # Iteration
sum, min, max, len, sorted, reversed # Aggregation
isinstance, type, hasattr, getattr # Introspection
all, any, abs, round, divmod # Math/logic
print # → server log
True, False, None # Constants
open, file # No file I/O
eval, exec, compile # No dynamic code execution
__import__ # No imports (this is the root cause)
globals, locals # No scope introspection
# Config: Reference DocType = Sales Invoice, Event = Before Save
if doc.grand_total < 0:
frappe.throw("Total MUST NOT be negative")
doc.requires_approval = 1 if doc.grand_total > 10000 else 0
# Config: API Method = get_customer_orders, Allow Guest = No
# Endpoint: /api/method/get_customer_orders
customer = frappe.form_dict.get("customer")
if not customer:
frappe.throw("Parameter 'customer' is required")
orders = frappe.get_all("Sales Order",
filters={"customer": customer, "docstatus": 1},
fields=["name", "grand_total", "status"],
order_by="creation desc",
limit=20
)
frappe.response["message"] = {"orders": orders, "count": len(orders)}
# Config: Event Frequency = Cron, Cron Format = 0 9 * * *
overdue = frappe.get_all("Sales Invoice",
filters={"status": "Unpaid", "due_date": ["<", frappe.utils.today()], "docstatus": 1},
fields=["name", "customer", "grand_total"]
)
for inv in overdue:
frappe.log_error(f"Overdue: {inv.name} ({inv.customer})", "Invoice Reminder")
frappe.db.commit() # ALWAYS commit in Scheduler scripts
# Config: Reference DocType = Sales Invoice
# Variables available: user, conditions
roles = frappe.get_roles(user)
if "System Manager" in roles:
conditions = ""
elif "Sales User" in roles:
conditions = f"`tabSales Invoice`.owner = {frappe.db.escape(user)}"
else:
conditions = "1=0"
| Feature | v14 | v15 | v16 |
|---|---|---|---|
| Server Scripts enabled | By default | Disabled by default | Disabled by default |
| Enable command | Not needed | bench set-config -g server_script_enabled 1 | Same as v15 |
| frappe.qb (Query Builder) | Available | Available | Available |
| run_script() for libraries | v13+ | Available | Available |
| frappe.make_get_request() | Available | Available | Available |
| Frappe Cloud shared bench | Supported | NOT supported | NOT supported |
import — everything is in the frappe namespacedoc.save() inside a Before Save script — causes infinite loopfrappe.db.commit() in Document Event scripts — framework handles itfrappe.db.commit() at the end of Scheduler scripts%(var)s with dict, NEVER f-strings in SQLGuide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).
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Use when implementation is complete, all tests pass, and you need to decide how to integrate the work - guides completion of development work by presenting structured options for merge, PR, or cleanup
Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).
React Native and Expo best practices for building performant mobile apps. Use when building React Native components, optimizing list performance, implementing animations, or working with native modules. Triggers on tasks involving React Native, Expo, mobile performance, or native platform APIs.
React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.
Next.js best practices - file conventions, RSC boundaries, data patterns, async APIs, metadata, error handling, route handlers, image/font optimization, bundling
Use when starting feature work that needs isolation from current workspace or before executing implementation plans - creates isolated git worktrees with smart directory selection and safety verification
Take impertio-studio/frappe-syntax-serverscripts from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.