Railway MCP Server

volume_create

Create persistent storage volumes for Railway services to handle database storage, persistent data, and file storage needs.

Instructions

[API] Create a new persistent volume for a service

⚡️ Best for: ✓ Setting up database storage ✓ Configuring persistent data ✓ Adding file storage

⚠️ Not for: × Temporary storage needs × Static file hosting × Memory caching

→ Prerequisites: service_list

→ Next steps: volume_list

→ Related: service_update, database_deploy

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": {
      "projectId": "<projectId>",
      "environmentId": "<environmentId>",
      "serviceId": "<serviceId>",
      "mountPath": "<mountPath>"
    },
    "name": "volume_create"
  }
}

Input Schema

Name	Required	Description
`projectId`	Yes	ID of the project containing the service
`environmentId`	Yes	ID of the environment for the volume (usually obtained from service_info)
`serviceId`	Yes	ID of the service to attach volume to
`mountPath`	Yes	Path where the volume should be mounted in the container

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jan 6, 2026

TDQS

A4/5.0

Behavior2/5

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

No annotations are provided, so the description bears full responsibility for behavioral disclosure. It only describes the action and prerequisites but does not mention permissions, rate limits, idempotency, error states, or whether the operation is destructive/reversible. This is a significant gap for a creation tool.

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 highly structured with emojis, bullet points, and clear sections. Every sentence adds value without redundancy. It is concise yet comprehensive for the information it conveys.

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?

Given no output schema, the description does not need to detail return values, but it could hint at the response format (e.g., volume ID). However, it effectively supplies prerequisites, next steps, and context with sibling tools, making it largely complete for a creation tool.

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?

Input schema covers all 4 parameters with descriptions, achieving 100% coverage. The description adds no additional meaning beyond the schema, so baseline 3 is appropriate. No extra context like formats or constraints is provided.

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 explicitly states 'Create a new persistent volume for a service' and lists specific use cases like database storage and persistent data. It distinguishes from sibling tools (volume_delete, volume_list, volume_update) with appropriate best-for/not-for categories.

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

Usage Guidelines5/5

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

The description provides clear when-to-use guidance with 'Best for' and 'Not for' sections, lists a prerequisite (service_list), next steps (volume_list), and related tools (service_update, database_deploy). This helps the agent decide when to invoke this tool vs alternatives.

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