VeChain MCP Server

Instructions

Implementation Reference

• src/tools.ts:576-599 (handler)

  Handler function that signs a raw VeChain transaction using the agent's secret key from environment variable. Decodes the hex input, signs with secp256k1, encodes, and returns the signed transaction hex.

  callback: async ({ rawTransaction }: { rawTransaction: string }) => {
      const secretKey = process.env.AGENT_SECRET_KEY
  
      if (!secretKey) {
          throw new Error("Missing AGENT_SECRET_KEY variable to use this tool.")
      }
  
      const secretKeyBytes = Address.of(secretKey).bytes
  
      const decodedTxBytes = Hex.of(rawTransaction).bytes
      const decodedTx = Transaction.decode(decodedTxBytes, true);
  
      const signedTx = decodedTx.sign(secretKeyBytes)
      const signedTxBytes = signedTx.encoded
      const signedTxHex = Hex.of(signedTxBytes).toString()
  
      return {
          content: [{
              type: "text",
              text: JSON.stringify(signedTxHex, null, 2)
          }]
      };
  
  }

• src/tools.ts:573-575 (schema)

  Zod input schema defining the required 'rawTransaction' parameter as a string (hex-encoded raw transaction).

  inputSchema: {
      rawTransaction: z.string(),
  },

• src/server.ts:74-92 (registration)

  Registration of all vechainTools (including sign_raw_transaction) with the MCP server using registerTool, passing name, schema, and wrapper around the tool's callback.

  for (const t of vechainTools) {
    server.registerTool(
      t.name,
      {
        title: t.name,
        description: t.description,
        inputSchema: t.inputSchema
      },
      async (args) => {
        const result = await t.callback(args);
        return {
          content: result.content.map(item => ({
            ...item,
            type: "text" as const
          }))
        };
      }
    );
  }