import { z } from "zod"
import { callNextJsTool } from "../_internal/nextjs-runtime-manager.js"
export const inputSchema = {
port: z
.union([z.string(), z.number()])
.transform((val) => (typeof val === "string" ? parseInt(val, 10) : val))
.describe("Port number of the Next.js dev server (required)."),
toolName: z
.string()
.describe(
"Name of the Next.js MCP tool to call (required). Use 'nextjs_index' first to discover available tool names."
),
args: z
.record(z.string(), z.unknown())
.optional()
.describe(
"Arguments object to pass to the Next.js MCP tool. MUST be an object (e.g., {param: 'value'}), NOT a string. Only provide this parameter if the tool requires arguments - omit it entirely for tools that take no arguments. Use 'nextjs_index' to see the inputSchema for each tool."
),
}
export const metadata = {
name: "nextjs_call",
description: `Call a specific MCP tool on a running Next.js development server.
REQUIREMENTS:
- Port number of the target Next.js dev server
- Tool name to execute
- Optional arguments object (if the tool requires parameters)
Use 'nextjs_index' first to discover available servers, tools, and their input schemas.
If 'nextjs_index' auto-discovery fails, ask the user for the port and call 'nextjs_index' again with the 'port' parameter.
IMPORTANT: When calling tools:
- The 'args' parameter MUST be an object (e.g., {key: "value"}), NOT a string
- If a tool doesn't require arguments, OMIT the 'args' parameter entirely - do NOT pass {} or "{}"
- Check the tool's inputSchema from 'nextjs_index' to see what arguments are required
Common Next.js MCP tools include:
- Error diagnostics (get compilation/runtime errors)
- Route information (list all routes)
- Build status (check compilation state)
- Cache management (clear caches)
- And more (varies by Next.js version)
Example usage:
1. Call 'nextjs_index' to see servers and tools
2. Call 'nextjs_call' with port=3000, toolName="get_errors" to get errors from server on port 3000`,
}
type NextjsCallArgs = {
port: string | number
toolName: string
args?: Record<string, unknown>
}
export async function handler(args: NextjsCallArgs): Promise<string> {
try {
if (!args.port) {
return JSON.stringify({
success: false,
error: "Port is required.",
hint: "Use 'nextjs_index' first to discover available servers and their ports. If auto-discovery fails, ask the user for the port and call 'nextjs_index' with the 'port' parameter.",
})
}
if (!args.toolName) {
return JSON.stringify({
success: false,
error: "toolName is required.",
hint: "Use 'nextjs_index' to discover available tool names for your server.",
})
}
// Ensure port is a number
const portNumber = typeof args.port === "string" ? parseInt(args.port, 10) : args.port
const result = await callNextJsTool(portNumber, args.toolName, args.args || {})
return JSON.stringify({
success: true,
port: portNumber,
toolName: args.toolName,
result,
})
} catch (error) {
const errorMessage = error instanceof Error ? error.message : String(error)
return JSON.stringify({
success: false,
error: errorMessage,
port: args.port,
toolName: args.toolName,
})
}
}
