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AGENTS.md

Guidance for node development in the nodes-base package.

Node Structure

Every node implements the INodeType interface with:

  • description: INodeTypeDescription - Node metadata and UI configuration
  • execute?() - For programmatic nodes
  • poll?() - For polling triggers (set polling: true in description)
  • trigger?() - For generic triggers
  • webhook?() - For webhook triggers
  • webhookMethods? - Webhook lifecycle (checkExists, create, delete)
  • methods? - loadOptions, listSearch, credentialTest, resourceMapping

Node Types

Programmatic Nodes

Use execute function for custom logic. Example: nodes/Discord/v2/DiscordV2.node.ts

Declarative Nodes

Use requestDefaults and routing configuration instead of execute. Example: nodes/Okta/Okta.node.ts

Trigger Nodes

  • Webhook triggers: Implement webhook and webhookMethods (checkExists, create, delete). Example: nodes/Microsoft/Teams/MicrosoftTeamsTrigger.node.ts
  • Polling triggers: Set polling: true and implement poll. Use getWorkflowStaticData('node') to persist state. Example: nodes/Google/Gmail/GmailTrigger.node.ts
  • Generic triggers: Implement trigger function. Example: nodes/MQTT/MqttTrigger.node.ts

Node Parameters

Common parameter types:

  • string - Text input
  • options - Dropdown (static or dynamic via loadOptionsMethod)
  • resourceLocator - Select by list, ID, or URL
  • collection - Key-value pairs
  • fixedCollection - Structured collections

Use displayOptions to show/hide fields based on other parameters. Use noDataExpression: true for resource/operation selectors.

Versioning

  • Light versioning: Use version arrays in description: version: [3, 3.1, 3.2]
  • Full versioning: Use VersionedNodeType class with separate version implementations. Example: nodes/Set/Set.node.ts

Credentials

Credentials are defined in credentials/ directory and implement ICredentialType:

  • name - Internal identifier
  • displayName - Human-readable name
  • properties - Credential fields
  • authenticate - Authentication configuration (generic or custom function)
  • test - Credential test request

Nodes can test credentials via methods.credentialTest.

Testing

Unit Tests

  • Use vitest-mock-extended for mocking interfaces
  • Use nock for HTTP mocking
  • Mock all external dependencies
  • Test happy paths, error handling, edge cases, and binary data

Workflow Tests

  • Use NodeTestHarness with JSON workflow definitions
  • Mock external APIs with nock
  • Use pnpm test for running tests. Example: cd packages/nodes-base/ && pnpm test TestFileName

Common Development Tasks

Creating a New Node

  1. Create directory: nodes/YourService/
  2. Create YourService.node.ts implementing INodeType
  3. Add icon SVG files in node directory
  4. Define credentials in credentials/ if needed
  5. Write tests following testing guidelines
  6. Register in package.json nodes array if needed

Adding Dynamic Options

Add loadOptionsMethod to parameter's typeOptions and implement method in methods.loadOptions.

Adding Resource Locator

Change parameter type to 'resourceLocator', define modes (list, id, url), add searchListMethod for list mode, add extractValue regex for URL mode.

Best Practices

TypeScript

  • Never use any type - use proper types or unknown
  • Avoid type casting with as - use type guards instead
  • Define interfaces for API responses

Error Handling

  • Use NodeOperationError for user-facing errors
  • Use NodeApiError for API-related errors
  • Support continueOnFail option when appropriate

Security

User input is untrusted. In nodes it arrives mainly through this.getNodeParameter(...) (and incoming item.json), and a workflow author controls these values.

Never use an untrusted value as a computed object key in an assignment. A value such as __proto__, constructor, or prototype pollutes the prototype chain:

// UNSAFE — `table`/`key` come from this.getNodeParameter(...)
if (acc[table] === undefined) acc[table] = {};
acc[table][key] = value;

Route dynamic-key writes through the n8n-workflow helpers, or build the accumulator as a Map / Object.create(null):

import { setSafeObjectProperty, isSafeObjectProperty } from 'n8n-workflow';

if (isSafeObjectProperty(table) && acc[table] === undefined) {
	setSafeObjectProperty(acc, table, {});
}

This only applies to dynamic-key writes (grouping/aggregating rows by a user-chosen column is the common case). Reads like const x = obj[key] are safe. Reference usage: nodes/Google/GSuiteAdmin/GSuiteAdmin.node.ts.

Code Organization

  • Separate operation/field descriptions into separate files
  • Create reusable API request helpers in GenericFunctions
  • Use kebab-case for files, PascalCase for classes

UI/UX

  • Use clear displayName and description fields
  • Set sensible default values
  • Use displayOptions to show/hide fields conditionally

Example Nodes

  • Declarative: nodes/Okta/Okta.node.ts
  • Programmatic: nodes/Discord/v2/DiscordV2.node.ts
  • Webhook Trigger: nodes/Microsoft/Teams/MicrosoftTeamsTrigger.node.ts
  • Polling Trigger: nodes/Google/Gmail/GmailTrigger.node.ts
  • Generic Trigger: nodes/MQTT/MqttTrigger.node.ts
  • Versioned: nodes/Set/Set.node.ts