fluent-sdk
Hybrid ServiceNow Development with NowSDK Fluent
Overview
This skill implements a three-tier development strategy for ServiceNow, routing each operation to the most capable tool:
TIER 1: NowSDK Fluent (metadata-as-code)
Flows, tables, business rules, catalog items, ACLs, scoped apps
TypeScript → build → deploy as scoped application
↓ falls through when...
- Runtime data operations needed
- Live instance queries required
- Existing record manipulation
TIER 2: MCP REST Tools (runtime operations)
CRUD on live data, queries, update set management, background scripts
Direct REST API calls to instance
↓ falls through when...
- REST API has documented limitations
- UI-only operations (Flow compilation, UI Policy action linking)
- Complex server-side operations not exposed via REST
TIER 3: Fix Scripts (manual fallback)
SN-Create-Fix-Script for operations neither tier can handle
Generated scripts for manual execution in instance
Used for: Flow compilation, UI Policy setValue(), complex GlideRecord ops
When to use this skill:
- "Build a new flow for incident escalation"
- "Create a scoped app with tables and business rules"
- "Set up a catalog item with approval workflow"
- "Deploy metadata changes with version control"
- "I need a flow but REST can't create flows"
Foundation: ServiceNow Official Fluent Skills
This skill builds on ServiceNow's official AI skills from github.com/ServiceNow/sdk:
vendor/now-sdk-setup.md— Environment setup (Node 20+, SDK install, auth). Run this first ifnow-sdkcommands fail.vendor/now-sdk-explain.md— Self-documenting SDK reference vianpx @servicenow/sdk explain. Always consult this before writing Fluent code — it covers every metadata type, convention, and project structure detail.
Before writing any Fluent code, follow the explain skill's protocol:
npx @servicenow/sdk explain <search-term> --list --format=raw— find relevant topicsnpx @servicenow/sdk explain <topic> --peek --format=raw— preview before committingnpx @servicenow/sdk explain <topic> --format=raw— read the full topic
This ensures you're using the latest API signatures and conventions, not stale examples.
Prerequisites
- Node.js: v20+ (
node --version) - NowSDK: v4.6.0+ (
npm install -g @servicenow/sdk@latest) - Instance: ServiceNow SDK plugin enabled, user has
adminorsn_sdk.userrole - MCP Server: happy-platform-mcp configured and connected
- Auth:
now-sdk authcompleted for target instance - Related Skills:
development/mcp-serverfor MCP tool reference,vendor/now-sdk-explain.mdfor Fluent API docs
Tier Decision Matrix
Use this matrix to determine which tier handles each operation:
| Operation | Tier 1 (Fluent) | Tier 2 (MCP REST) | Tier 3 (Fix Script) |
|---|---|---|---|
| Create flow with logic | YES - full Flow DSL | No - cannot create flows | No |
| Compile/publish flow | Automatic on deploy | No | YES - manual in UI |
| Create table + schema | YES - Table() with typed columns |
Yes - but no version control | No |
| Business rules | YES - BusinessRule() with scripts |
Yes - SN-Create-Record on sys_script |
No |
| Catalog items | YES - CatalogItem() with variables |
Yes - but UI policies limited | Partial |
| UI Policy actions | YES - deployed with app | No - REST can't link actions | YES - setValue() script |
| ACLs | YES - Acl() definition |
Yes - SN-Create-Record on sys_security_acl |
No |
| Script includes | YES - with server modules | Yes - SN-Create-Record on sys_script_include |
No |
| Query live data | No - not for runtime | YES - SN-Query-Table |
No |
| Update existing records | No - creates new metadata | YES - SN-Update-Record |
No |
| Update set management | Automatic on deploy | YES - SN-Set-Update-Set, inspect, move |
No |
| Background script execution | No | YES - SN-Execute-Background-Script |
No |
| Scoped app creation | YES - now.config.json defines scope |
Yes - SN-Create-Record on sys_app |
No |
| Deploy to instance | YES - now-sdk deploy |
No - records created individually | No |
| Complex GlideRecord ops | No | Partial | YES - full server-side API |
Procedure
Step 1: Environment Setup
Follow vendor/now-sdk-setup.md to verify NowSDK is installed and working:
# Check Node version (must be 20+)
node --version
# Check SDK version (must be 4.6.0+)
npx @servicenow/sdk --version
# If not installed or outdated:
npm install -g @servicenow/sdk@latest
# Authenticate to your instance
now-sdk auth
# Follow prompts: instance URL, credentials
Verify with explain command:
npx @servicenow/sdk explain quickstart --list --format=raw
Then familiarize yourself with the Fluent API for whatever you're about to build:
# Example: about to create flows
npx @servicenow/sdk explain Flow --list --peek --format=raw
npx @servicenow/sdk explain Flow --format=raw
Step 2: Determine the Right Tier
Before writing any code, classify the request:
Route to Tier 1 (Fluent) when:
- Creating new metadata from scratch (flows, tables, business rules, catalog items)
- Building a scoped application
- Need version-controlled, reproducible deployments
- Flow Designer operations (REST API cannot create flows)
- Complex catalog items with variable sets, pricing, access controls
Route to Tier 2 (MCP REST) when:
- Querying or modifying live data
- Managing update sets (inspect, move, clone)
- One-off record updates on existing records
- Running background scripts
- Verifying Tier 1 deployments
Route to Tier 3 (Fix Script) when:
- Flow compilation (must happen in UI after deploy)
- UI Policy action linking via
setValue() - Complex GlideRecord operations not exposed via REST
- Bulk data operations requiring server-side performance
Step 3: Scaffold a Fluent Project (Tier 1)
Create the project structure for a new scoped application.
Project Structure:
my-sn-app/
├── now.config.json # Scope and instance config
├── package.json # Dependencies
├── tsconfig.json # TypeScript config (optional)
├── src/
│ └── fluent/
│ ├── generated/
│ │ └── keys.ts # Auto-generated sys_id mappings
│ ├── tables.now.ts # Table definitions
│ ├── rules.now.ts # Business rules
│ ├── flows.now.ts # Flow definitions
│ ├── catalog.now.ts # Catalog items
│ ├── acls.now.ts # Access controls
│ └── *.server.js # External script files
└── src/
└── server/ # Server-side TypeScript modules
now.config.json:
{
"scope": "x_myapp",
"scopeId": "<sys_id from instance or generated on first deploy>"
}
package.json:
{
"name": "my-sn-app",
"version": "1.0.0",
"scripts": {
"build": "now-sdk build",
"deploy": "now-sdk deploy",
"explain": "now-sdk explain"
},
"devDependencies": {
"@servicenow/glide": "catalog:",
"@servicenow/sdk": "catalog:",
"typescript": "catalog:"
}
}
Step 4: Write Fluent Definitions
Tables
// src/fluent/tables.now.ts
import {
Table, StringColumn, IntegerColumn, BooleanColumn,
DateColumn, ReferenceColumn
} from '@servicenow/sdk/core'
export const x_myapp_request = Table({
name: 'x_myapp_request',
schema: {
title: StringColumn({ mandatory: true, label: 'Title', maxLength: 200 }),
priority: IntegerColumn({ mandatory: true, label: 'Priority' }),
active: BooleanColumn({ mandatory: true, label: 'Active', default: true }),
due_date: DateColumn({ label: 'Due Date' }),
assigned_to: ReferenceColumn({
label: 'Assigned To',
referenceTable: 'sys_user',
}),
},
})
Business Rules
// src/fluent/rules.now.ts
import { BusinessRule } from '@servicenow/sdk/core'
export const validatePriority = BusinessRule({
$id: Now.ID['validate_priority'],
name: 'Validate Priority on Create',
active: true,
table: 'x_myapp_request',
when: 'before',
insert: true,
script: Now.include('./validate-priority.server.js'),
})
// src/fluent/validate-priority.server.js
(function executeRule(current, previous) {
if (!current.priority || current.priority < 1 || current.priority > 5) {
current.priority = 3; // Default to medium
}
if (!current.assigned_to && current.priority == 1) {
gs.addErrorMessage('Critical requests must have an assignee');
current.setAbortAction(true);
}
})(current, previous);
Flows
// src/fluent/flows.now.ts
import { action, Flow, wfa, trigger } from '@servicenow/sdk/automation'
export const escalationFlow = Flow(
{
$id: Now.ID['request_escalation_flow'],
name: 'Request Escalation Flow',
description: 'Escalates high-priority requests when unassigned after creation',
},
wfa.trigger(
trigger.record.created,
{ $id: Now.ID['new_request_trigger'] },
{
table: 'x_myapp_request',
condition: 'priority=1^assigned_toISEMPTY',
run_flow_in: 'background',
run_on_extended: 'false',
run_when_setting: 'both',
run_when_user_setting: 'any',
run_when_user_list: [],
}
),
(params) => {
// Log the escalation
wfa.action(
action.core.log,
{ $id: Now.ID['log_escalation'] },
{
log_level: 'warn',
log_message: `Escalating unassigned critical request: ${wfa.dataPill(params.trigger.current.title, 'string')}`,
}
)
// Look up the on-call manager
const manager = wfa.action(
action.core.lookUpRecord,
{ $id: Now.ID['lookup_oncall_manager'] },
{
table: 'sys_user',
conditions: 'active=true^roles=manager',
sort_type: 'sort_asc',
if_multiple_records_are_found_action: 'use_first_record',
}
)
// Auto-assign to manager
wfa.action(
action.core.updateRecord,
{ $id: Now.ID['assign_to_manager'] },
{
table_name: 'x_myapp_request',
record: wfa.dataPill(params.trigger.current.sys_id, 'reference'),
values: TemplateValue({
assigned_to: wfa.dataPill(manager.Record.sys_id, 'reference'),
}),
}
)
// Send notification
wfa.action(
action.core.sendEmail,
{ $id: Now.ID['notify_manager'] },
{
table_name: 'x_myapp_request',
watermark_email: true,
ah_subject: `Critical Request Escalation: ${wfa.dataPill(params.trigger.current.title, 'string')}`,
ah_body: `A critical request has been auto-assigned to you.`,
record: wfa.dataPill(params.trigger.current.sys_id, 'reference'),
ah_to: wfa.dataPill(manager.Record.email, 'string'),
}
)
}
)
Catalog Items
// src/fluent/catalog.now.ts
import {
CatalogItem, VariableSet, SingleLineTextVariable,
MultiLineTextVariable, SelectBoxVariable, ReferenceVariable,
RequestedForVariable
} from '@servicenow/sdk/core'
const requestInfoVarSet = VariableSet({
$id: Now.ID['request_info_varset'],
title: 'Request Details',
description: 'Core information for the request',
internalName: 'request_info_varset',
type: 'singleRow',
layout: 'normal',
order: 100,
displayTitle: true,
version: 1,
variables: {
requestTitle: SingleLineTextVariable({
question: 'Request Title',
mandatory: true,
order: 100,
}),
requestDescription: MultiLineTextVariable({
question: 'Description',
mandatory: true,
order: 200,
}),
requestPriority: SelectBoxVariable({
question: 'Priority',
mandatory: true,
order: 300,
choices: {
critical: { label: '1 - Critical' },
high: { label: '2 - High' },
medium: { label: '3 - Medium' },
low: { label: '4 - Low' },
},
defaultValue: 'medium',
}),
},
name: 'Request Details',
})
export const newRequestCatalogItem = CatalogItem({
$id: Now.ID['new_request_catalog_item'],
name: 'New Service Request',
shortDescription: 'Submit a new service request',
description: 'Use this form to submit a service request. Critical requests trigger automatic escalation.',
catalogs: ['e0d08b13c3330100c8b837659bba8fb4'], // Service Catalog
categories: ['d258b953c611227a0146101fb1be7c31'], // Hardware (or your category)
variableSets: [{ variableSet: requestInfoVarSet, order: 100 }],
executionPlan: '523da512c611228900811a37c97c2014',
variables: {
requestedFor: RequestedForVariable({
order: 1,
question: 'Requested For',
}),
assignmentGroup: ReferenceVariable({
order: 2,
question: 'Assignment Group',
referenceTable: 'sys_user_group',
}),
},
})
Step 5: Build and Deploy (Tier 1)
# Build the project (validates TypeScript, generates metadata)
now-sdk build
# Deploy to instance (creates/updates scoped app and all metadata)
now-sdk deploy
Step 6: Verify with MCP Tools (Tier 2)
After Fluent deployment, use MCP tools to verify everything landed correctly.
Tool: SN-Query-Table
Parameters:
table_name: sys_update_xml
query: application=<app_sys_id>
fields: sys_id,type,name,sys_created_on
limit: 50
Tool: SN-Get-Table-Schema
Parameters:
table_name: x_myapp_request
Tool: SN-Query-Table
Parameters:
table_name: sys_script
query: collection=x_myapp_request^active=true
fields: name,when,active
Step 7: Handle Fallthrough to Fix Scripts (Tier 3)
For operations that neither Fluent nor REST can handle, generate fix scripts.
Flow Compilation (post-deploy):
Tool: SN-Create-Fix-Script
Parameters:
name: "Compile Escalation Flow"
description: "Compile the request escalation flow after Fluent deployment"
script: |
// Navigate to Flow Designer and compile:
// 1. Open Flow Designer
// 2. Find "Request Escalation Flow"
// 3. Click "Activate" to compile and enable
//
// This step cannot be automated - Flow Designer compilation
// requires the UI runtime environment.
gs.info('Manual step: Compile flow in Flow Designer UI');
UI Policy Action Linking (if needed):
Tool: SN-Execute-Background-Script
Parameters:
script: |
var gr = new GlideRecord('sys_ui_policy_action');
gr.addQuery('ui_policy', '<ui_policy_sys_id>');
gr.addQuery('catalog_variable', '');
gr.query();
while (gr.next()) {
gr.catalog_variable = 'IO:<variable_sys_id>';
gr.update();
}
description: "Link UI Policy actions to catalog variables"
execution_method: trigger
Bulk Data Operations:
Tool: SN-Create-Fix-Script
Parameters:
name: "Seed Sample Data"
description: "Create initial sample records for testing"
script: |
var records = [
{ title: 'Test Request 1', priority: 1 },
{ title: 'Test Request 2', priority: 3 },
{ title: 'Test Request 3', priority: 5 }
];
records.forEach(function(data) {
var gr = new GlideRecord('x_myapp_request');
gr.initialize();
gr.title = data.title;
gr.priority = data.priority;
gr.active = true;
gr.insert();
});
gs.info('Created ' + records.length + ' sample records');
Hybrid Workflow Example
A complete end-to-end example combining all three tiers:
GOAL: Build a scoped app with escalation flow, catalog item, and seed data
TIER 1 (Fluent):
1. Create now.config.json with scope
2. Define table schema in tables.now.ts
3. Define business rules in rules.now.ts
4. Define escalation flow in flows.now.ts
5. Define catalog item in catalog.now.ts
6. now-sdk build && now-sdk deploy
TIER 2 (MCP REST):
7. SN-Query-Table → verify all records in update set
8. SN-Get-Table-Schema → confirm table columns created
9. SN-Query-Table on sys_script → verify business rules active
10. SN-Execute-Background-Script → seed sample data
TIER 3 (Fix Script):
11. SN-Create-Fix-Script → flow compilation instructions
12. SN-Create-Fix-Script → any UI Policy action linking
13. Manual: compile flow in Flow Designer UI
NowSDK Explain Reference
The SDK has built-in documentation accessible via CLI:
# List all available topics
npx @servicenow/sdk explain --list --format=raw
# Search for a topic
npx @servicenow/sdk explain flow --list --peek --format=raw
# Read full topic (only after previewing)
npx @servicenow/sdk explain flow --format=raw
# Key topics:
# quickstart - Getting started
# Table - Table definitions
# Flow - Flow automation
# BusinessRule - Business rule definitions
# CatalogItem - Service catalog items
# Acl - Access control lists
# ScriptInclude - Script includes
# naming - Naming conventions
# structure - Project structure
Important: Always use --peek first before reading a full topic to avoid wasting context on irrelevant content.
Fluent API Quick Reference
Imports by Module
// Core metadata
import {
Table, StringColumn, IntegerColumn, BooleanColumn,
DateColumn, ReferenceColumn, Record, BusinessRule,
ScriptInclude, ClientScript, Acl, Role
} from '@servicenow/sdk/core'
// Flow automation
import {
Flow, Subflow, action, wfa, trigger
} from '@servicenow/sdk/automation'
// Catalog
import {
CatalogItem, VariableSet, SingleLineTextVariable,
MultiLineTextVariable, SelectBoxVariable, ReferenceVariable,
CheckBoxVariable, DateTimeVariable, RequestedForVariable,
EmailVariable
} from '@servicenow/sdk/core'
Key Helpers
| Helper | Purpose | Example |
|---|---|---|
Now.ID['key'] |
Reference a record by key name | $id: Now.ID['my_rule'] |
Now.include('./file.js') |
Include external script file | script: Now.include('./rule.server.js') |
Now.ref(export) |
Cross-reference another Fluent export | table: Now.ref(myTable) |
Now.attach('./file') |
Attach file to record | attachment: Now.attach('./logo.png') |
TemplateValue({}) |
Set field values in flow actions | values: TemplateValue({ state: '2' }) |
wfa.dataPill(ref, type) |
Reference flow data pills | wfa.dataPill(params.trigger.current.sys_id, 'reference') |
Flow Logic Blocks
// Conditional
wfa.flowLogic.if({ $id, condition, annotation }, () => { ... })
wfa.flowLogic.elseIf({ $id, condition, annotation }, () => { ... })
wfa.flowLogic.else({ $id }, () => { ... })
// Loops
wfa.flowLogic.forEach(dataPill, { $id }, () => { ... })
// Subflow outputs
wfa.flowLogic.assignSubflowOutputs({ $id }, params.outputs, { ... })
Flow Actions (action.core.*)
| Action | Purpose |
|---|---|
action.core.log |
Log message with level |
action.core.lookUpRecord |
Query for a single record |
action.core.updateRecord |
Update a record |
action.core.createRecord |
Create a new record |
action.core.sendEmail |
Send email notification |
action.core.sendSms |
Send SMS |
action.core.sendNotification |
Send notification via template |
Flow Triggers (trigger.record.*)
| Trigger | Fires When |
|---|---|
trigger.record.created |
Record created |
trigger.record.updated |
Record updated |
trigger.record.createdOrUpdated |
Record created or updated |
trigger.record.deleted |
Record deleted |
Troubleshooting
NowSDK Not Found
npm install -g @servicenow/sdk@latest
# Verify: npx @servicenow/sdk --version (must be 4.6.0+)
Auth Failures
# Re-authenticate
now-sdk auth
# Ensure instance has SDK plugin enabled
# Ensure user has admin or sn_sdk.user role
Build Errors
# Check explain docs for the specific type
npx @servicenow/sdk explain <TypeName> --format=raw
# Common issues:
# - Missing $id on records → add Now.ID['unique_key']
# - Invalid column types → check Table column type imports
# - Script file not found → verify Now.include() path is relative to .now.ts file
Deploy Creates Wrong Scope
Verify now.config.json has the correct scope and scopeId. The scopeId should match the sys_id of the sys_app record on your instance.
Fallthrough: When Fluent Fails
If now-sdk deploy fails for specific record types, fall through:
- Check if MCP REST can create the record directly (
SN-Create-Record) - If REST also fails, generate a fix script (
SN-Create-Fix-Script) - Document the limitation for future reference
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