@primeuix/mcp v1.0.1 fails to start with @modelcontextprotocol/sdk >= 1.28.x

[ryansorensen]

Description

The MCP server fails to start with the following error:

  Failed to start PrimeVue MCP Server: Error: Tool get_composable expected a Zod schema or ToolAnnotations, but received an unrecognized object
      at McpServer.tool (file:///.../@modelcontextprotocol/sdk/dist/esm/server/mcp.js:688:27)

Root Cause

In @primeuix/mcp, the internal F function that registers custom tools (passed via the customTools option) calls McpServer.tool() with a plain JSON object as the input schema:

function F(a, e, n) {
    for (let c of n) {
        let r = {};
        for (let [l, t] of Object.entries(c.parameters))
            r[l] = { type: t.type, description: t.description }; // ❌ plain object
        a.tool(c.name, c.description, r, ...);
    }
}

Starting with @modelcontextprotocol/sdk v1.28.x, McpServer.tool() now strictly validates that the schema argument is either a Zod schema or a ToolAnnotations object. Passing a plain object with nested values (like { name: { type: "string", description: "..." } }) throws an error.

Since @primeuix/mcp depends on "@modelcontextprotocol/sdk": "^1.25.2", users will automatically get a version that breaks the server.

Fix

The F function should convert parameter definitions to Zod schemas and use registerTool() instead of tool():

function F(a, e, n) {
    for (let c of n) {
        let r = {};
        for (let [l, t] of Object.entries(c.parameters)) {
            let schema = t.type === "boolean" ? z.boolean()
                       : t.type === "number"  ? z.number()
                       : z.string();
            r[l] = t.description ? schema.describe(t.description) : schema;
        }
        a.registerTool(c.name, { description: c.description, inputSchema: r }, ...);
    }
}

Steps to Reproduce

npx -y @primevue/mcp

Environment

• @primevue/mcp: 4.5.4
• @primeuix/mcp: 1.0.1
• @modelcontextprotocol/sdk: 1.29.0 (resolved via ^1.25.2)

[nicogtm]

Looks like what #229 aims to fix. Also affects the PrimeNG MCP. Would be nice to have the MCP back soon. :)

[HeldvonKosmos]

Here is a patch script.

const fs = require('fs');
const path = 'node_modules/@modelcontextprotocol/sdk/dist/esm/server/mcp.js';

if (fs.existsSync(path)) {
    let content = fs.readFileSync(path, 'utf8');
    const search = /throw new Error\(`Tool \${name} expected a Zod schema or ToolAnnotations, but received an unrecognized object`\);/;
    const replace = `return console.warn(\`Skipping invalid tool definition for: \${name}\`);`;
    
    if (content.match(search)) {
        content = content.replace(search, replace);
        fs.writeFileSync(path, content);
        console.log("✅ Patch erfolgreich angewendet!");
    } else {
        console.log("⚠️ Suchmuster nicht gefunden. Ist der Patch schon aktiv?");
    }
} else {
    console.error("❌ Datei nicht gefunden. Pfad prüfen!");
}

Just run "node patch_mcp.js" and then "node ./node_modules/@primevue/mcp/dist/index.js"

I know this is just a quick fix but until the main problem is fixed this might help.

Same issue also for @primevue/mcp

[csteve64-JHU]

A few on our team are currently blocked by this.

We got through it by adding "@primevue/mcp": "4.5.5" to the root package.json's devDependencies and an override

"pnpm": {
	"overrides": {
		"@modelcontextprotocol/sdk": "1.26.0"
	},
}

Just got this going and seems solid. Will report back if it reveals itself to be fault.