it-tools-mcp/build/tools/crypto/decode_jwt/index.js

MCP-compliant server access to over 100 IT tools and utilities commonly used by developers, system administrators, and IT professionals.

import { z } from "zod";
export function registerDecodeJwt(server) {
    server.registerTool("decode_jwt", {
        inputSchema: {
            token: z.string().describe("JWT token to decode"),
        },
        // VS Code compliance annotations
        annotations: {
            title: "Decode Jwt",
            readOnlyHint: false
        }
    }, async ({ token }) => {
        try {
            const parts = token.split('.');
            if (parts.length !== 3) {
                throw new Error("Invalid JWT format. JWT must have 3 parts separated by dots.");
            }
            const header = JSON.parse(Buffer.from(parts[0], 'base64url').toString());
            const payload = JSON.parse(Buffer.from(parts[1], 'base64url').toString());
            return {
                content: [
                    {
                        type: "text",
                        text: `JWT Token Decoded:

Header:
${JSON.stringify(header, null, 2)}

Payload:
${JSON.stringify(payload, null, 2)}

Note: Signature verification is not performed. Do not trust this token without proper verification.`,
                    },
                ],
            };
        }
        catch (error) {
            return {
                content: [
                    {
                        type: "text",
                        text: `Error decoding JWT: ${error instanceof Error ? error.message : 'Unknown error'}`,
                    },
                ],
            };
        }
    });
}