Neo4j MCP Server

neo4j_insert_relationship

Create a relationship between two existing nodes by specifying their labels and unique matching properties, along with the relationship type and optional properties.

Instructions

Create a relationship between two existing nodes (matched by label + properties).

Args: from_label: Label of the source node. from_properties: Properties to match the source node (must be unique). rel_type: Relationship type (e.g. "PAGOU", "PERTENCE"). to_label: Label of the target node. to_properties: Properties to match the target node (must be unique). rel_properties: Optional properties on the relationship itself.

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": {
      "from_label": "<from_label>",
      "from_properties": "<from_properties>",
      "rel_type": "<rel_type>",
      "to_label": "<to_label>",
      "to_properties": "<to_properties>"
    },
    "name": "neo4j_insert_relationship"
  }
}

Input Schema

Name	Required	Description	Default
`rel_type`	Yes
`to_label`	Yes
`from_label`	Yes
`to_properties`	Yes
`rel_properties`	No
`from_properties`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 9, 2026

TDQS

A3.6/5.0

Behavior2/5

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

No annotations are provided, so the description must cover behavioral traits. It only states that the relationship is created between existing nodes, but does not disclose what happens if nodes are not found, whether the operation is idempotent, or any side effects. This is insufficient for safe invocation.

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 concise, uses a clear docstring format, and front-loads the action. The Args section is efficient, though not every sentence is essential. No wasted words.

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

Completeness3/5

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

An output schema exists, so return value documentation is not required. However, the description lacks information on error handling, constraints (e.g., relationship uniqueness), and success indicators. It is minimally complete for a tool with 6 parameters and no annotations.

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

Parameters4/5

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

Schema description coverage is 0%, so the description must compensate. It explains each parameter's purpose, notes that from_properties and to_properties must be unique, and clarifies rel_properties is optional. This adds significant meaning beyond the raw 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 verb 'create' and the resource 'relationship', and specifies that nodes are matched by label and properties. It distinguishes from siblings like 'neo4j_insert' (creates nodes) and 'neo4j_search_relationships' (searches relationships).

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 should be used when creating a relationship, but does not provide explicit guidance on when to use it versus alternatives (e.g., neo4j_insert for nodes, neo4j_update for modifying nodes). No exclusion criteria or prerequisites are mentioned.

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

Deploy Server