variable_set
Set or update environment variables for services on railway-mcp, ideal for configuring values, managing secrets, and updating connection strings. Use for individual variable changes.
Instructions
[API] Create or update an environment variable
⚡️ Best for: ✓ Setting configuration values ✓ Updating connection strings ✓ Managing service secrets
⚠️ Not for: × Bulk variable updates (use variable_bulk_set) × Temporary configuration changes
→ Prerequisites: service_list
→ Alternatives: variable_bulk_set
→ Next steps: deployment_trigger, service_restart
→ Related: variable_list, variable_delete
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| environmentId | Yes | ID of the environment for the variable (usually obtained from service_list) | |
| name | Yes | Name of the environment variable | |
| projectId | Yes | ID of the project containing the service | |
| serviceId | No | Optional: ID of the service for the variable, if omitted creates/updates a shared variable | |
| value | Yes | Value to set for the variable |
Implementation Reference
- src/tools/variable.tool.ts:60-62 (handler)The execution handler for the 'variable_set' tool, which delegates to the variable service's upsertVariable method.async ({ projectId, environmentId, name, value, serviceId }) => { return variableService.upsertVariable(projectId, environmentId, name, value, serviceId); }
- src/tools/variable.tool.ts:53-59 (schema)Zod input schema defining parameters for the 'variable_set' tool.{ projectId: z.string().describe("ID of the project containing the service"), environmentId: z.string().describe("ID of the environment for the variable (usually obtained from service_list)"), name: z.string().describe("Name of the environment variable"), value: z.string().describe("Value to set for the variable"), serviceId: z.string().optional().describe("Optional: ID of the service for the variable, if omitted creates/updates a shared variable") },
- src/tools/variable.tool.ts:32-63 (registration)Creates and registers the 'variable_set' tool, including its metadata, schema, and handler. This is included in the exported variableTools array.createTool( "variable_set", formatToolDescription({ type: 'API', description: "Create or update an environment variable", bestFor: [ "Setting configuration values", "Updating connection strings", "Managing service secrets" ], notFor: [ "Bulk variable updates (use variable_bulk_set)", "Temporary configuration changes" ], relations: { prerequisites: ["service_list"], nextSteps: ["deployment_trigger", "service_restart"], alternatives: ["variable_bulk_set"], related: ["variable_list", "variable_delete"] } }), { projectId: z.string().describe("ID of the project containing the service"), environmentId: z.string().describe("ID of the environment for the variable (usually obtained from service_list)"), name: z.string().describe("Name of the environment variable"), value: z.string().describe("Value to set for the variable"), serviceId: z.string().optional().describe("Optional: ID of the service for the variable, if omitted creates/updates a shared variable") }, async ({ projectId, environmentId, name, value, serviceId }) => { return variableService.upsertVariable(projectId, environmentId, name, value, serviceId); } ),
- Helper service method that performs the actual upsert (create or update) of the environment variable by calling the API client.async upsertVariable(projectId: string, environmentId: string, name: string, value: string, serviceId?: string) { try { await this.client.variables.upsertVariable({ projectId, environmentId, name, value, serviceId }); const variableType = serviceId ? "service variable" : "shared environment variable"; return createSuccessResponse({ text: `Successfully set ${variableType} "${name}"` }); } catch (error) { return createErrorResponse(`Error setting variable: ${formatError(error)}`); } }