using-n8n-mcp-skills

Using the n8n-mcp Skills

This is a router, not a reference. It tells you which skill owns the rules for what you're about to do. The skill bodies hold the actual guidance — invoke them with the Skill tool. When in doubt, load more skills rather than fewer.

The community n8n-mcp server and n8n itself move faster than any model's training cutoff. Tool names, parameters, node typeVersions, and default behaviors drift between releases. When you spot drift — a tool a skill names doesn't exist, a parameter shape doesn't match what get_node returns, behavior differs from what a skill describes — trust the live tool, tell the user, and suggest updating the pack and the instance.

Non-negotiables

Three rules with no exceptions. Each one prevents a class of workflow that looks correct but breaks in production.

1. Invoke the relevant skill before any n8n action — not just before MCP calls. Before writing an expression, configuring a node, designing a workflow, wiring a connection, or writing Code, invoke the matching skill. The PreToolUse hooks remind you on the highest-impact tool calls only when the plugin bundle is installed; on Claude.ai (plain skill uploads, no hooks) the responsibility is entirely yours.
2. Validate AND verify before activating. Run validate_workflow (or n8n_validate_workflow by id) before you activate, and call n8n_get_workflow after every create or update to inspect the connections object. Validation alone misses silently dropped wires, Merge index off-by-one, and error outputs that were never wired. Validation passing means the JSON is well-formed — not that the workflow is correct.
3. Secrets never go in text fields. Tokens, API keys, and passwords always go through the n8n credential system. If no native node exists, use the HTTP Request node with the official credential type. A Set node holding a token referenced via {{ $json.token }} is a leak with extra steps. See n8n-mcp-tools-expert.

Lean on skills, not training data

n8n changes constantly. "Remembered" parameter names are often silently wrong — they validate as plain strings and then do nothing at runtime. Trust the skills and the live tools (get_node, search_nodes, tools_documentation) over recollection. If a skill contradicts your memory, trust the skill. If get_node contradicts a skill, trust the tool and flag the drift.

Strong defaults

Each skill owns its own exceptions; these are the defaults.

• The Code node is a last resort. Expression first, then an arrow function inside Edit Fields, then a Code node only when neither can do the job. See n8n-code-javascript.
• A Set node feeding 0–1 consumers is almost always wrong. Inline the expression at the consumer instead. See n8n-expression-syntax.
• Per-item iteration is automatic. Don't add a Loop Over Items node to "make it loop" when default per-item execution already handles the case.
• Configure from the live schema, never from memory. get_node before you set parameters. See n8n-node-configuration.

Red flags: "about to ___" → invoke ___

If you catch yourself thinking any of these, stop and invoke the named skill first.

Thought	Invoke
"This workflow is simple, I'll just build it"	n8n-workflow-patterns — most "simple" flows ship at 10+ nodes
"I'll add a Set node to map these fields"	n8n-expression-syntax — Set feeding ≤1 consumer is the #1 antipattern
"I'll just use a Code node, it's easier"	n8n-code-javascript — the bar is high; most reaches are expressions or Edit Fields
"The user mentioned data, I'll write Python"	n8n-code-javascript — default JS; Python (n8n-code-python) only on explicit ask
"I'm writing code an AI agent will call"	n8n-code-tool — a different runtime contract from the Code node
"Date math — I'll drop in a DateTime node"	n8n-expression-syntax — Luxon inline is almost always right
"I'll wire a Merge with 3 sources"	n8n-node-configuration — Merge defaults to 2 inputs; the 3rd silently drops
"Validation passed, I'm ready to activate"	n8n-validation-expert + n8n-workflow-patterns — run the antipattern scan
"Validation threw an error I don't understand"	n8n-validation-expert — some warnings are false positives, some errors are real
"I'll reference $json.x here"	n8n-expression-syntax — prefer $('Node').item.json.x in branchy workflows
"This webhook/scheduled flow is happy-path only"	n8n-error-handling — wire an error branch on every fallible node; 4xx caller faults, 5xx yours
"I'll pass this file/image through as JSON"	n8n-binary-and-data — file contents live in $binary, and can't cross the agent-tool boundary
"I'll wire up an AI agent and give the model some tools"	n8n-agents — tool names & descriptions ARE the prompt; memory, structured output, and topology have traps
"I'll copy this logic into another workflow" / "this is getting big"	n8n-subworkflows — extract a reusable sub-workflow; search before building
"I'll create that credential / open that workflow" (account has >1 instance)	n8n-multi-instance — every call hits the currently-targeted instance; reads misroute silently, and an ambiguous credential write fails closed with INSTANCE_AMBIGUOUS

Skill index

Skill	Reach for it when
using-n8n-mcp-skills	This router (auto-loaded). Names the skill that owns your task.
n8n-mcp-tools-expert	Choosing or calling any n8n-mcp tool; node discovery; credentials; data tables; security audit; templates
n8n-workflow-patterns	Designing or building a workflow; picking an architecture (webhook / HTTP API / database / AI agent / scheduled / batch)
n8n-node-configuration	Configuring any node; operation-aware required fields; property dependencies; surgical field edits
n8n-expression-syntax	Writing {{ }}, $json/$node/$now; mapping data between nodes; the transform gatekeeper; Set-node discipline
n8n-validation-expert	Interpreting validation errors/warnings; false positives; the validation loop; auto-fix; reviewing an existing workflow
n8n-code-javascript	Any Code node in JavaScript; data access; this.helpers; DateTime; SplitInBatches loop patterns
n8n-code-python	A Code node specifically requested in Python; standard-library limits
n8n-code-tool	The AI-agent-callable Custom Code Tool (toolCode) — returns a string, no $fromAI/$input
n8n-error-handling	Webhook/API or unattended workflows; wiring error outputs; retries; 4xx/5xx response shapes; silent failures
n8n-binary-and-data	Files, images, PDFs, attachments, uploads/downloads, vision; passing a file to/from an agent tool
n8n-subworkflows	Reusable / multi-step builds; Execute Workflow; extracting shared logic; Define-Below inputs; all-vs-each; exposing a workflow as an agent tool
n8n-agents	AI Agent / LLM-with-tools / Text Classifier; tool design & $fromAI; system prompts; structured output; memory; RAG; human review; chat bots
n8n-multi-instance	Accounts with multiple instances (the n8n_instances tool is present); switching the target instance; verifying before credential writes; recovering from an unexpected NOT_FOUND, wrong/empty reads, or an INSTANCE_AMBIGUOUS credential-write fail-close
n8n-self-hosting	Deployment, not workflow-building — self-hosting / installing / deploying n8n on a VM (Docker Compose + Caddy, single vs queue mode), or updating / backing up / hardening it. Triggers on its own; not part of the build flow above.

n8n-mcp tools — working knowledge from turn one

Qualified names look like mcp__<server>__<tool> (<server> is usually n8n-mcp). This closes the gap where a tool's full description isn't loaded until first use.

Discovery & docs

• tools_documentation — meta-docs for every tool; {topic:"ai_agents_guide", depth:"full"} for the agent guide.
• search_nodes — find nodes by keyword.
• get_node — node info. Takes a single SHORT-form nodeType (nodes-base.httpRequest, nodes-langchain.agent), plus detail (minimal/standard/full) and mode (info/docs/search_properties/versions).
• validate_node — validate one node's config in isolation (profiles: minimal/runtime/ai-friendly/strict).
• search_templates / get_template — the template library (by keyword, nodes, task, metadata).

Build & edit

• n8n_create_workflow — create from full workflow JSON.
• n8n_update_partial_workflow — incremental diff ops ({id, operations:[…]}): addNode, updateNode, patchNodeField, addConnection, activateWorkflow, etc. Preferred for edits.
• n8n_update_full_workflow — full replacement.
• n8n_autofix_workflow — auto-fix common issues.
• n8n_generate_workflow / n8n_deploy_template — generate or deploy a template to the instance.

Validate (necessary, not sufficient — always pair with the antipattern scan)

• validate_workflow — full JSON in, errors/warnings/fixes out. Node types here are LONG form (n8n-nodes-base.set).
• n8n_validate_workflow — validate a deployed workflow by {id} (no node JSON to inspect).

Inspect & lifecycle

• n8n_get_workflow — fetch a workflow (full / structure / active / filtered / minimal). Use it to verify connections after edits; mode="filtered" + nodeNames reads one heavy node (e.g. long Code source) without pulling the whole workflow, which can truncate client-side.
• n8n_list_workflows — list/filter (search before duplicating logic).
• n8n_delete_workflow, n8n_workflow_versions (history/rollback), n8n_instances (multi-instance accounts only: list/switch the target instance — see n8n-multi-instance), n8n_health_check (returns the resolved instanceName).

Test & run

• n8n_test_workflow — runs real nodes (Code, HTTP, DB writes, sends all fire). Ask the user before running when side effects exist.
• n8n_executions — list/inspect executions. There is no execute_workflow tool.

Data, credentials, audit

• n8n_manage_datatable — Data Table CRUD, filtering, dry-run.
• n8n_manage_credentials — credential CRUD + getSchema discovery.
• n8n_audit_instance — security audit (hardcoded secrets, unauthenticated webhooks, error-handling gaps).

Node-type form trap: get_node / validate_node take SHORT form (nodes-base.set); workflow JSON inside validate_workflow / n8n_create_workflow uses LONG form (n8n-nodes-base.set). Mixing them is a common, silent mistake — see n8n-mcp-tools-expert.

The protocol, in order

1. Recognize the matching skill from the index and invoke it before the first MCP call.
2. Skim tools_documentation once per session to refresh the tool surface if you're unsure.
3. get_node before configuring any node — read the live schema, don't assume.
4. Build / edit, then validate_workflow before activating and n8n_get_workflow after to check connections.
5. Surface any drift you notice (missing tool, changed parameter, diverging behavior).

When in doubt

• Can't find a workflow the user built in the UI? The most common cause is per-workflow MCP access being off. Ask them to open it in n8n, go to Settings, and enable MCP access.
• User says it's broken? Believe them. Re-check parameters against get_node, trace data references, inspect the execution. See n8n-validation-expert.
• No skill fits and the task is non-trivial? Ask before guessing.

These are opinionated best practices, not laws. Disagree with a call? It's all markdown — edit the skill.