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variable_copy

Copy environment variables from one Railway environment to another for migration, configuration sharing, or duplication workflows.

Instructions

[WORKFLOW] Copy variables from one environment to another

⚡️ Best for: ✓ Environment migration ✓ Configuration sharing ✓ Environment duplication

⚠️ Not for: × Single variable updates (use variable_set) × Temporary configuration changes

→ Prerequisites: service_list

→ Alternatives: variable_set

→ Next steps: deployment_trigger, service_restart

→ Related: variable_list, service_update

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
projectIdYesID of the project
sourceEnvironmentIdYesID of the source environment (usually obtained from project_info)
targetEnvironmentIdYesID of the target environment (usually obtained from project_info)
serviceIdNoID of the service (optional, if omitted copies shared variables)
overwriteNoWhether to overwrite existing variables in the target environment

Implementation Reference

  • Registers the 'variable_copy' MCP tool using createTool, providing formatted description, input schema, and handler function that delegates to VariableService.copyVariables
    createTool(
      "variable_copy",
      formatToolDescription({
        type: 'WORKFLOW',
        description: "Copy variables from one environment to another",
        bestFor: [
          "Environment migration",
          "Configuration sharing",
          "Environment duplication"
        ],
        notFor: [
          "Single variable updates (use variable_set)",
          "Temporary configuration changes"
        ],
        relations: {
          prerequisites: ["service_list"],
          nextSteps: ["deployment_trigger", "service_restart"],
          alternatives: ["variable_set"],
          related: ["variable_list", "service_update"]
        }
      }),
      {
        projectId: z.string().describe("ID of the project"),
        sourceEnvironmentId: z.string().describe("ID of the source environment (usually obtained from project_info)"),
        targetEnvironmentId: z.string().describe("ID of the target environment (usually obtained from project_info)"),
        serviceId: z.string().optional().describe("ID of the service (optional, if omitted copies shared variables)"),
        overwrite: z.boolean().optional().default(false).describe("Whether to overwrite existing variables in the target environment")
      },
      async ({ projectId, sourceEnvironmentId, targetEnvironmentId, serviceId, overwrite = false }) => {
        return variableService.copyVariables(projectId, sourceEnvironmentId, targetEnvironmentId, serviceId, overwrite);
      }
    )
  • Zod input schema defining parameters for the variable_copy tool: projectId, sourceEnvironmentId, targetEnvironmentId, optional serviceId, and optional overwrite flag
    {
      projectId: z.string().describe("ID of the project"),
      sourceEnvironmentId: z.string().describe("ID of the source environment (usually obtained from project_info)"),
      targetEnvironmentId: z.string().describe("ID of the target environment (usually obtained from project_info)"),
      serviceId: z.string().optional().describe("ID of the service (optional, if omitted copies shared variables)"),
      overwrite: z.boolean().optional().default(false).describe("Whether to overwrite existing variables in the target environment")
    },
  • Handler function for the variable_copy tool, which invokes VariableService.copyVariables with the provided parameters
    async ({ projectId, sourceEnvironmentId, targetEnvironmentId, serviceId, overwrite = false }) => {
      return variableService.copyVariables(projectId, sourceEnvironmentId, targetEnvironmentId, serviceId, overwrite);
    }
  • Core helper method implementing the variable copying logic: retrieves variables from source and target environments, filters based on overwrite flag, performs bulk upsert, and returns success/error responses
    async copyVariables(projectId: string, sourceEnvironmentId: string, targetEnvironmentId: string, serviceId?: string, overwrite: boolean = false) {
      try {
        // Get variables from source environment
        const sourceVars = await this.client.variables.getVariables(projectId, sourceEnvironmentId, serviceId);
    
        if (Object.keys(sourceVars).length === 0) {
          return createSuccessResponse({
            text: "No variables found in source environment to copy.",
            data: { copied: 0 }
          });
        }
    
        // Get variables from target environment
        const targetVars = await this.client.variables.getVariables(projectId, targetEnvironmentId, serviceId);
    
        // If not overwriting, filter out variables that already exist in target
        const varsToSet = overwrite
          ? sourceVars
          : Object.fromEntries(
              Object.entries(sourceVars).filter(([key]) => !(key in targetVars))
            );
    
        if (Object.keys(varsToSet).length === 0) {
          return createSuccessResponse({
            text: "All variables already exist in target environment.",
            data: { copied: 0 }
          });
        }
    
        // Bulk update the variables
        await this.bulkUpsertVariables(projectId, targetEnvironmentId, varsToSet, serviceId);
    
        const variableType = serviceId ? "service variables" : "shared environment variables";
        return createSuccessResponse({
          text: `Successfully copied ${Object.keys(varsToSet).length} ${variableType} to target environment`,
          data: { copied: Object.keys(varsToSet).length }
        });
      } catch (error) {
        return createErrorResponse(`Error copying variables: ${formatError(error)}`);
      }
    }

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A3.9/5.0
Behavior3/5

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

No annotations provided, so description must carry burden. It describes the copy operation and overwrite flag but does not explicitly state that it modifies the target environment, potential destructive behavior, or permissions needed. Could be more transparent about mutation and risks.

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?

Well-structured with emojis, bullet points, and clear sections. Front-loaded purpose. Some verbosity due to multiple sections, but overall efficient and scannable.

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

Completeness2/5

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

No output schema, so description should cover return value. It does not describe what the tool returns (e.g., success message, count of copied variables). Provides prerequisites and next steps, but misses result explanation for a tool with 5 parameters.

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%, baseline 3. The description adds minimal extra meaning beyond schema: source/target environment IDs from project_info, serviceId optional for shared variables, overwrite flag. No further parameter context.

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 copies variables from one environment to another, using specific verbs and resource. It distinguishes from sibling tools like variable_set (single variable updates) and variable_list.

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?

Provides explicit sections: Best for (environment migration, sharing, duplication), Not for (single variable updates, temp changes), Prerequisites (service_list), Alternatives (variable_set), Next steps (deployment_trigger, service_restart), and Related tools. Excellent guidance on when to use and when not.

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