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verzth

n8n MCP Server

by verzth

List n8n Variables

n8n_list_variables
Read-onlyIdempotent

List all global workflow variables (key-value pairs) used across every n8n workflow. Control result size with limit and navigate pages using cursor.

Instructions

List all workflow variables (global key-value pairs available in all workflows).

Args:

  • limit (number): Max results (1-250, default 20)

  • cursor (string?): Pagination cursor

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
limitNo
cursorNo
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations (readOnly, idempotent, non-destructive), the description adds behavioral context about pagination via the cursor parameter and limit default, as well as clarifying that variables are global across workflows. This is useful context not present in the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is brief and front-loaded with the purpose, followed by a compact parameter list. Every sentence earns its place with no redundancy or fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple list tool with two optional parameters and no output schema, the description covers purpose, parameter semantics, and pagination behavior. It does not describe the return structure, but that is somewhat self-evident for a list operation. Overall, it is nearly complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has no descriptions, but the description compensates fully by documenting limit (range and default) and cursor as a pagination cursor. This adds meaning beyond the raw type and constraints in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool lists all workflow variables, defining them as global key-value pairs available in all workflows. This uses a specific verb and resource, and distinguishes it from sibling tools like n8n_list_workflows and n8n_create_variable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The usage context is implied: you use this to list variables. However, it does not explicitly mention alternatives or when not to use it (e.g., 'use n8n_create_variable to add variables'). The readOnlyHint annotation partially covers this, but the description itself provides no direct guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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