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n8n MCP Server

n8n MCP Server

by verzth
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Local

Delete n8n Variable

n8n_delete_variable
Destructive

Remove a workflow variable by its ID. Deleting it causes workflows referencing it to get undefined, helping clean up unused variables.

Instructions

Delete a workflow variable. Workflows referencing it will get undefined.

Args:

  • id (string): Variable ID to delete

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "id": "<id>"
    },
    "name": "n8n_delete_variable"
  }
}

Input Schema

NameRequiredDescriptionDefault
idYesVariable ID to delete

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv1.0.0

TDQS

A3.9/5.0
Behavior4/5

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

The description adds a critical behavioral consequence: 'Workflows referencing it will get undefined.' This goes beyond the annotations (which already flag destructiveHint) and provides useful context about the impact of deletion. It could mention permissions or irreversibility, but the added side-effect note is valuable.

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

Conciseness4/5

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

The description is very short and front-loaded with the primary action and effect. The 'Args' section duplicates schema information but is not verbose; the overall structure is efficient and easy to parse.

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 one-parameter delete tool with annotations indicating destructiveness, the description is sufficiently complete. It explains the key side effect and does not need to elaborate on return values given the simplicity and the presence of annotations. However, it does not explicitly state what the response will be, which is a minor gap.

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

Parameters3/5

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

Schema coverage is 100% and the description repeats the same information as the schema ('id (string): Variable ID to delete') without adding additional meaning. The schema already fully documents the parameter, so the description contributes no extra semantic value.

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 uses a specific verb 'Delete' with a clear resource 'workflow variable', and the resource type distinguishes it from sibling delete tools like n8n_delete_workflow or n8n_delete_credential. The purpose is immediately clear and unambiguous.

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 description implies the tool is used to remove a workflow variable, but it does not explicitly state when to prefer it over alternatives like update or create, nor does it mention any exclusions or prerequisites. Usage context is implied rather than clearly contrasted with sibling tools.

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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