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AGENTS.md

This file provides guidance on how to work with the n8n repository.

Project Overview

n8n is a workflow automation platform written in TypeScript, using a monorepo structure managed by pnpm workspaces. It consists of a Node.js backend, Vue.js frontend, and extensible node-based workflow engine.

General Guidelines

  • Always use pnpm
  • Write all technical text (code comments, PR descriptions, issue and ticket descriptions, docs) in ASD-STE100 Simplified Technical English: use short sentences, the active voice, and one instruction for each sentence
  • JSDoc on @Env(...) config properties is public documentation. The docs team exports these comments into the environment variable reference on docs.n8n.io. Write them for a self-hosting operator and follow the n8n:env-var-docs skill, which applies the n8n docs style guide and overrides the ASD-STE100 rule above for these comments
  • Secrets on the command line: if a developer opted into anonymous dev metrics (scripts/dev-metrics), pnpm command arguments are recorded. Arguments of secret-carrying words (config, login, publish, token) — whether a subcommand or baked into a flag — are dropped, and the home dir is stripped from paths, but other args are sent as-is — so never put secrets in a command. Pass sensitive values via environment variables, which are never captured.
  • When adding comments, keep them concise and to the point - explain the "why" in a line or two; don't be overly verbose. Comments should be scoped and relevant to the surrounding code, not just to the current task
  • We use Linear as a ticket tracking system
  • We use Posthog for feature flags
  • To find registered telemetry events (names, descriptions, properties), run pnpm --filter @n8n/telemetry catalog (--json for structured output). The registry is being adopted incrementally, so search call sites if the catalog has no match. The n8n:telemetry skill covers adding or changing events
  • When starting to work on a new ticket – create a new branch from fresh master with the name specified in Linear ticket
  • When creating a new branch for a ticket in Linear - use the branch name suggested by Linear, unless it is a security fix (see Security Fix Hygiene below)
  • Use mermaid diagrams in MD files when you need to visualise something
  • Write an ADR only when asked. When a change makes a decision that an engineer could challenge in 12 months, say so in one line and let the human decide. Read docs/adr/README.md before you write one. CI enforces its conventions
  • Developing v3 features: land normal feature work on master behind an opt-in flag; introduce breaking changes only on the 3.x branch. See .github/DEVELOPING_V3.md.
  • The AI gateway feature is "Gateway credits" in user-facing text (UI copy, error messages, prompts). Only internal identifiers, i18n keys, telemetry, and comments keep the historical n8nConnect / n8n credits / AI Gateway names
  • Shared utilities: before you hand-roll a utility (isRecord, secret or PII redaction, JSON extraction from LLM output, Zod to JSON Schema, model-id parsing, AI client HTTP transport and response-size limiting, …), you MUST check the shared packages for an existing implementation and use it: @n8n/utils (generic helpers, redaction), @n8n/ai-utilities (AI- and LLM-specific helpers) and n8n-workflow (workflow graph and traversal). A new shared helper usually belongs in one of these packages too; domain logic stays in the package that owns the domain.

Agent Skills and Claude Code Plugin

n8n shared skills live in .agents/skills/. Claude Code consumes them through symlinks in .claude/plugins/n8n/skills/; OpenCode reads .agents/skills/ directly. Harness-specific overrides remain real directories in the harness path, such as .opencode/skills/setup-mcps/. See skills README for editing and sync guidance.

n8n-specific Claude Code commands and agents live in .claude/plugins/n8n/ and are namespaced under n8n:. Use n8n: prefix when invoking them (e.g. /n8n:create-pr, /n8n:plan, n8n:developer agent). See plugin README for structure and details.

Essential Commands

For routine pre-commit checks, follow Verify changes. For focused tests, use pnpm agent:test or pnpm agent:playwright. Pass test files and worker limits after --. Run each command with --help for its options.

pnpm agent:lint and pnpm agent:typecheck run full-repo checks by default. With --filter <package>, they still check the whole package. These wrappers save logs and reduce console output. They do not reduce CPU or memory use. Do not use them as routine pre-commit checks.

Fresh checkout / agent setup

For a fresh checkout (cat-bot, a new hire, any agent verifying the repo builds), prefer pnpm agent:setup over running install + build + tests by hand. It chains them in one process, caps per-process memory and turbo concurrency so a 6GB box doesn't OOM, streams all output to .agent-setup/<step>.log (gitignored), and surfaces only a one-line summary per step plus the tail of the failing log. A machine-readable .agent-setup/summary.json is always written so a backgrounded run is readable in a single shot — no polling, no scrolling logs.

pnpm agent:setup                 # install → build → test (full suite)
pnpm agent:setup install         # one step at a time
pnpm agent:setup --json          # JSON summary on stdout (for scripts/agents)

Building

Use pnpm build to build all packages. ALWAYS redirect the output of the build command to a file:

pnpm build > build.log 2>&1

You can inspect the last few lines of the build log file to check for errors:

tail -n 20 build.log

If build outputs or the turbo cache are stale (e.g. after switching branches or worktrees) but dependencies haven't changed, use pnpm reset (lightweight by default) for a fast recovery: it cleans build outputs and force-rebuilds (keeping node_modules and untracked files). If that doesn't fix your issue, use pnpm reset --full, which also wipes untracked files and reinstalls dependencies.

Seeding a local instance

An empty instance is a bad place to test anything that reads a user's work. These commands fill one. They are dev tooling on the private root package, so they never reach a user.

N8N_API_KEY=<jwt> pnpm seed:preference   # 10 workflows in one house style, plus history
N8N_API_KEY=<jwt> pnpm seed:account      # ~500 varied workflows across 30 projects
pnpm inspect:activity                    # read-only activity_event viewer on 127.0.0.1

Both seed profiles delete their own prior output, so a re-run replaces it. That clear step deletes anything named [seed] and any empty team project, whoever made them, so do not point either at a shared instance. The viewer is unauthenticated and serves the whole table: keep it on loopback.

See scripts/instance-seeding/AGENTS.md for profiles, tokens, determinism, and the other commands.

Architecture Overview

Monorepo Structure: pnpm workspaces with Turbo build orchestration

Package Structure

The monorepo is organized into these key packages:

  • packages/@n8n/api-types: Shared TypeScript interfaces between frontend and backend
  • packages/workflow: Core workflow interfaces and types
  • packages/core: Workflow execution engine
  • packages/cli: Express server, REST API, and CLI commands
  • packages/frontend/editor-ui: Vue 3 frontend application
  • packages/frontend/@n8n/i18n: Internationalization for UI text
  • packages/nodes-base: Built-in nodes for integrations
  • packages/@n8n/nodes-langchain: AI/LangChain nodes
  • packages/@n8n/instance-ai: "n8n Assistant" in the UI, "Instance AI" in code — n8n Assistant backend. See its CLAUDE.md for architecture docs.
  • @n8n/design-system: Vue component library for UI consistency
  • @n8n/config: Centralized configuration management

Technology Stack

  • Frontend: Vue 3 + TypeScript + Vite + Pinia + Storybook UI Library
  • Backend: Node.js + TypeScript + Express + TypeORM
  • Testing: Vitest (unit) + Playwright (UI, API, infrastructure, lifecycle, performance, and E2E orchestration)
  • Database: TypeORM with SQLite/PostgreSQL support
  • Code Quality: Biome (for formatting) + ESLint + lefthook git hooks

Key Architectural Patterns

  1. Dependency Injection: Uses @n8n/di for IoC container
  2. Controller-Service-Repository: Backend follows MVC-like pattern
  3. Event-Driven: Internal event bus for decoupled communication
  4. Context-Based Execution: Different contexts for different node types
  5. State Management: Frontend uses Pinia stores
  6. Design System: Reusable components and design tokens are centralized in @n8n/design-system, where all pure Vue components should be placed to ensure consistency and reusability

Key Development Patterns

  • Each package has isolated build configuration and can be developed independently
  • Hot reload works across the full stack during development
  • Node development uses dedicated node-dev CLI tool
  • Workflow tests are JSON-based for integration testing
  • AI features have dedicated development workflow (pnpm dev:ai)

Workflow Traversal Utilities

The n8n-workflow package exports graph traversal utilities from packages/workflow/src/common/. Use these instead of custom traversal logic.

Key concept: workflow.connections is indexed by source node. To find parent nodes, use mapConnectionsByDestination() to invert it first.

import { getParentNodes, getChildNodes, mapConnectionsByDestination } from 'n8n-workflow';

// Finding parent nodes (predecessors) - requires inverted connections
const connectionsByDestination = mapConnectionsByDestination(workflow.connections);
const parents = getParentNodes(connectionsByDestination, 'NodeName', 'main', 1);

// Finding child nodes (successors) - uses connections directly
const children = getChildNodes(workflow.connections, 'NodeName', 'main', 1);

TypeScript Best Practices

  • NEVER use any type - use proper types or unknown
  • Avoid type casting with as - use type guards or type predicates instead (except in test code where as is acceptable)
  • Define shared interfaces in @n8n/api-types package for FE/BE communication
  • Lazy-load heavy modules — if a module is only used in a specific code path (not every request), use await import() at point of use instead of top-level import. Applies especially to native modules and large parsers.

Error Handling

  • Don't use the deprecated ApplicationError class anywhere — it's a compatibility shim kept only so community nodes keep resolving. Use one of these instead, picking by cause:
    • UserError — the user caused it (invalid input, unauthorized action, business-rule violation).
    • OperationalError — a transient, expected issue (network request failing, DB query timing out) that should be handled gracefully.
    • UnexpectedError — a bug in the code (logic mistake, unhandled case, failed assertion) that developers need to fix.
  • Import from appropriate error classes in each package

Persistence layer & the TypeORM boundary

TypeORM (@n8n/typeorm) must stay in the persistence layer. The shared @n8n/db package and backend persistence adapters can import it. A module can colocate or group its entities and repositories according to its domain. Business logic — services, controllers, handlers, commands, factories — must not import from @n8n/typeorm (including @n8n/typeorm/... subpaths). The typeorm-persistence-boundary Code Health rule recognizes entity and repository declarations. It scans backend packages that depend on @n8n/db or @n8n/typeorm. Tests, migrations, and explicit helper-only adapters are exceptions. Existing business-logic imports stay in the shrink-only Code Health baseline. A new business-logic import fails CI.

  • Pattern: when a query needs operators (In, IsNull, LessThan, FindOptionsWhere, …), put it behind a use-case-named repository method that takes plain parameters and returns domain-shaped values — not a generic find(options) passthrough.
  • Transactions: transaction orchestration belongs in the persistence layer. Don't reach for .manager / .manager.transaction(...) or createQueryBuilder(...) in business logic. Use the sanctioned primitive in @n8n/db: inject the abstract TransactionRunner and wrap the unit of work in txRunner.run(ctx, async (ctx) => …). The callback receives an OperationContext carrying the active transaction; thread that ctx into the repository methods you call. run requires a context — pass an empty {} at the operation entry point, and reuse the one you were handed everywhere below it (a context that already carries a transaction is joined, not nested). Repositories extend BaseRepository and resolve the right EntityManager with this.managerFor(ctx); the Transaction handle is opaque and never exposes a driver type to business logic. See oauth-token.service.ts + oauth-*-token.repository.ts for a worked example.
  • Anti-patterns reviewers reject — they hide the dependency instead of removing it:
    • String-matching TypeORM errors, e.g. error.name === 'QueryFailedError'.
    • Relabeling the import from @n8n/typeorm to @n8n/db to silence the rule (@n8n/db re-exports several operators/types, but this relabels the dependency rather than removing it).
    • Pushing .manager / createQueryBuilder into business logic to avoid an operator import — trades a visible leak for an invisible one.

ESLint configuration layers

Rule policy lives in four shared configs in @n8n/eslint-config, and a package config picks exactly one:

layer subpath for
baseConfig @n8n/eslint-config/base runtime-agnostic libraries
backendConfig @n8n/eslint-config/backend anything that runs on Node; adds the network and encryption boundaries
frontendConfig @n8n/eslint-config/frontend Vue packages
nodesConfig @n8n/eslint-config/nodes n8n-nodes-base and @n8n/nodes-langchain; adds the node and credential file rules

A package config may add ignores, an additive plugin config, a block that raises rules to error, and blocks scoped to files. It must not turn a rule down for the whole package: every lint script runs with --quiet, so a warn enforces nothing and reads as if it did. The code-health rule lint-config-layering enforces this, with existing debt in .code-health-baseline.json, which only shrinks.

To stop enforcing a rule everywhere, retire it in base.ts with the count behind the decision. To enforce one again in a package that is ready, set it to error there. node scripts/lint-parity/majority.mjs prints how many packages downgrade each rule, and scripts/lint-parity/snapshot.mjs plus diff.mjs prove a config change only altered what you meant it to.

Encryption boundary

New code encrypts and decrypts only through cipher.encryptV2() / cipher.decryptV2() — the key-manager module decides which key is used and in which output format. Enforced in CI by the rules in packages/@n8n/eslint-config/src/configs/encryption-boundary.ts (part of backendConfig, and so of nodesConfig; every package that runs on Node extends one of those layers):

  • Cipher does not expose the legacy or explicit-key methods.
  • The raw AES classes stay inside packages/core/src/encryption/.
  • Deployment keys are never deleted — data encrypted with a key becomes unreadable without it. Deactivate keys instead; the repository does not expose deletion and database triggers reject direct deletion.
  • Inline disables that name these rules, and bare line-form disables, are themselves lint errors. The code-health rule encryption-boundary (CI "Static Analysis") is the enforcement layer: it checks that every package that depends on n8n-core or @n8n/db extends backendConfig (or nodesConfig) at error severity, and rejects every directive form that would silence the rules in non-test code (eslint-disable* and inline eslint configuration comments). Widening the boundary happens in encryption-boundary.ts only; that file and the rule files require security (IAM) approval via OWNERS.

Frontend Development

  • Refer to packages/frontend/AGENTS.md
  • All UI text must use i18n - add translations to @n8n/i18n package
  • Use CSS variables directly - never hardcode spacing as px values
  • data-testid must be a single value (no spaces or multiple values)
  • Always use the design-system skill in reviews

Verify changes

  • Before committing, run formatting and lint checks on changed files. Use the package's configured tools through pnpm exec with explicit file paths. Do not append file paths to pnpm lint; package scripts can still check the whole package.
  • Run tests that cover the changed behavior from the owning package: pnpm test <test-file> --maxWorkers=1. Or use the root wrapper: pnpm agent:test --filter <package> -- <test-file> --maxWorkers=1. For Playwright, use pnpm agent:playwright -- <spec-file> --workers=1.
  • For routine commits, run checks one at a time. Use one test worker by default. Do not run full frontend typechecks locally. Use CI for comprehensive lint, typechecks, and test suites.
  • For documentation-only changes, review the diff and run git diff --check. Skip code tests when no behavior changed.
  • Report which checks ran and which checks were left to CI.
  • Use Vitest for unit tests. Use Playwright when a test needs its browser, fixtures, or managed containers.
  • For Vitest packages with @n8n/di decorators, use createVitestConfigWithDecorators from @n8n/vitest-config/node-decorators.
  • Check import and mock side effects before running tests. Keep tests out of user-owned directories. Set N8N_USER_FOLDER to a test-owned directory before importing n8n settings. Clean up only paths that the test created.
  • CI runs @n8n/code-health static analysis on PRs. It checks monorepo rules, including dependency hygiene and encryption-boundary coverage.

Local development

Goal Command
Run product E2E against a local instance pnpm --filter=n8n-playwright test:local
Run backend with PostgreSQL, Redis, email, and proxy services pnpm --filter n8n-containers services --services postgres,redis,mailpit,proxy, then pnpm dev:be
Add editor hot reload pnpm dev:fe:editor
Start a Codespace backend and share its port pnpm dev:up

The root pnpm dev command does not start a server. See the Playwright guide and the Codespaces guide for details.

Common Development Tasks

When implementing features:

  1. Define API types in packages/@n8n/api-types
  2. Implement backend logic in packages/cli module, follow scripts/backend-module/backend-module-guide.md
  3. Add API endpoints via controllers
  4. Update frontend in packages/frontend/editor-ui with i18n support. For a frontend feature module, obey packages/@n8n/module-cli/frontend-module-guide.md
  5. Write tests with proper mocks

Design Principles

Security Must Not Degrade the Building Experience

Security improvements, whether driven by enterprise requirements or internal standards, must NEVER add friction to the common-case building experience. When designing security-related features (defaults, behaviors, flows, error handling), apply these checks:

  • No friction for the common case: A community builder's workflow should remain intuitive. Security should be invisible when it can be.
  • Migration and upgrade paths: Existing users must have a clear, non-disruptive path forward when defaults or behaviors change.
  • Security layers on top, not in competition: Great UX and strong security are not trade-offs. They're both required. If a design forces a choice between them, the design needs more work.

Security Fix Hygiene

This is a public repository. When working on security fixes, never expose the attack vector or vulnerability type in any public-facing artifact. Attackers monitor open-source repos for signals like branch names, commit messages, PR titles, test descriptions, and Linear URLs.

Rules for security fixes:

  • Branch names: Do NOT use the Linear-suggested branch name if it reveals the vulnerability. Rename to describe the fix neutrally (e.g. node-1234-improve-request-handling, not node-1234-fix-ddos-vulnerability).
  • Commit messages: Describe what the code now does, not the threat it prevents (e.g. fix: add payload size validation, not fix: prevent denial of service).
  • Test descriptions: Use neutral, functional language (e.g. 'should sanitize query parameters', not 'should prevent SQL injection').
  • Code comments: Do not describe the attack scenario in comments.
  • Linear references: Never include the URL slug (e.g. .../N8N-1234/fix-ssrf-vulnerability).

Customer Confidentiality

This is a public repository. Never mention customer names in any public-facing artifact — not all customers have agreed to be named publicly, and naming them can reveal security-relevant details about their setup.

This applies to PR titles and descriptions, branch names, commit messages, code, code comments, test names and test data, and fixtures. When implementing a customer request, describe the use case neutrally (e.g. "a customer with a large multi-main setup", not the company name) and use generic placeholder names (e.g. Acme Corp) in tests and examples.

Github Guidelines

  • When creating a PR, use the conventions in .github/pull_request_template.md and .github/pull_request_title_conventions.md.
  • Use gh pr create --draft to create draft PRs.
  • If there is a corresponding Linear ticket, reference it in the PR description using https://linear.app/n8n/issue/[TICKET-ID]. Do not create a Linear ticket on your own — ask first.
  • always link to the github issue if mentioned in the linear ticket.