diff --git a/integration-tests/formating/formatting.test.ts b/integration-tests/formating/formatting.test.ts
index d683088c..2ce2ad55 100644
--- a/integration-tests/formating/formatting.test.ts
+++ b/integration-tests/formating/formatting.test.ts
@@ -32,12 +32,29 @@ describe('Command formatting tests', async () => {
                 expect(flag, `Flag '${flagName}' in command '${command.cmd.id}' is missing the 'required' property`).to.have.property('required');
                 
                 if(flag.type === 'option') {
-                    console.log(flag);
                     expect(flag, `Flag '${flagName}' in command '${command.cmd.id}' is missing a valid 'helpValue'`).to.have.property('helpValue').to.be.a('string').and.not.be.empty;
                 }
             }
         }
     });
+
+    it('Should ensure all itwin-id flags have env properties', async () => {
+        for (const command of allCommands) {
+            const iTwinIdFlag = command.flags.find(([name, _]) => name === "itwin-id");
+            if (iTwinIdFlag) {
+                expect(iTwinIdFlag[1].env, `Flag 'itwin-id' in command '${command.cmd.id}' is missing the 'env' property`).to.be.a('string').and.be.equals("ITP_ITWIN_ID");
+            }
+        }
+    });
+
+    it('Should ensure all imodel-id flags have env properties', async () => {
+        for (const command of allCommands) {
+            const iTwinIdFlag = command.flags.find(([name, _]) => name === "imodel-id");
+            if (iTwinIdFlag) {
+                expect(iTwinIdFlag[1].env, `Flag 'imodel-id' in command '${command.cmd.id}' is missing the 'env' property`).to.be.a('string').and.be.equals("ITP_IMODEL_ID");
+            }
+        }
+    });
 });
 
 type CommandWithFlags = {
diff --git a/src/commands/access-control/group/create.ts b/src/commands/access-control/group/create.ts
index 52c9a475..d8602a6e 100644
--- a/src/commands/access-control/group/create.ts
+++ b/src/commands/access-control/group/create.ts
@@ -7,6 +7,7 @@ import { Flags } from "@oclif/core";
 
 import { apiReference } from "../../../extensions/api-reference.js";
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class CreateAccessControlGroup extends BaseCommand {
     static apiReference : apiReference = {
@@ -30,11 +31,8 @@ export default class CreateAccessControlGroup extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the group is being created.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the group is being created.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/access-control/group/delete.ts b/src/commands/access-control/group/delete.ts
index 2f3da96f..e8df09a4 100644
--- a/src/commands/access-control/group/delete.ts
+++ b/src/commands/access-control/group/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class DeleteAccessControlGroup extends BaseCommand {
     static description = 'Delete an existing group from an iTwin.';
@@ -24,11 +25,8 @@ export default class DeleteAccessControlGroup extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin where the group exists.',
-        helpValue: '<string>',
-        required: true,
       }),
     };
   
diff --git a/src/commands/access-control/group/info.ts b/src/commands/access-control/group/info.ts
index c75d5edc..2f3f28f6 100644
--- a/src/commands/access-control/group/info.ts
+++ b/src/commands/access-control/group/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class AccessControlGroupInfo extends BaseCommand {
     static description = 'Retrieve details about a specific group in an iTwin.';
@@ -24,11 +25,8 @@ export default class AccessControlGroupInfo extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the group exists.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the group exists.'
       }),
     };
   
diff --git a/src/commands/access-control/group/list.ts b/src/commands/access-control/group/list.ts
index b9e573fe..d8aec489 100644
--- a/src/commands/access-control/group/list.ts
+++ b/src/commands/access-control/group/list.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListAccessControlGroups extends BaseCommand {
     static description = 'List all groups for a specific iTwin.';
@@ -18,11 +17,8 @@ export default class ListAccessControlGroups extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin whose groups you want to list.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin whose groups you want to list.'
       }),
     };
   
diff --git a/src/commands/access-control/group/update.ts b/src/commands/access-control/group/update.ts
index 436e9a10..c3a57113 100644
--- a/src/commands/access-control/group/update.ts
+++ b/src/commands/access-control/group/update.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class UpdateAccessControlGroup extends BaseCommand {
     static description = 'Update the details of an existing group in an iTwin.';
@@ -38,11 +39,8 @@ export default class UpdateAccessControlGroup extends BaseCommand {
         helpValue: '<string>',
         multiple: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the group exists.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the group exists.'
       }),
       member: Flags.string({
         description: 'A list of members (emails) to be assigned to the group.',
diff --git a/src/commands/access-control/member/group/add.ts b/src/commands/access-control/member/group/add.ts
index 48d0d53b..f46aa50d 100644
--- a/src/commands/access-control/member/group/add.ts
+++ b/src/commands/access-control/member/group/add.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 import { GroupMember } from "../../../../services/access-control-client/models/group.js";
 
 export default class AddGroupMembers extends BaseCommand {
@@ -24,11 +25,8 @@ export default class AddGroupMembers extends BaseCommand {
         helpValue: '<string>',
         required: true
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the groups will be added.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to which the groups will be added.'
       }),
     };
   
diff --git a/src/commands/access-control/member/group/delete.ts b/src/commands/access-control/member/group/delete.ts
index cf1c49f2..73e8436e 100644
--- a/src/commands/access-control/member/group/delete.ts
+++ b/src/commands/access-control/member/group/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class DeleteGroupMember extends BaseCommand {
     static description = 'Remove a group from an iTwin.';
@@ -24,11 +25,8 @@ export default class DeleteGroupMember extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the group is a member.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the group is a member.'
       }),
     };
   
diff --git a/src/commands/access-control/member/group/info.ts b/src/commands/access-control/member/group/info.ts
index d04574c1..5a1f7953 100644
--- a/src/commands/access-control/member/group/info.ts
+++ b/src/commands/access-control/member/group/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class InfoGroupMember extends BaseCommand {
     static description = 'Retrieve details about a specific group member in an iTwin.';
@@ -24,11 +25,8 @@ export default class InfoGroupMember extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the group is a member.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the group is a member.'
       }),
     };
   
diff --git a/src/commands/access-control/member/group/list.ts b/src/commands/access-control/member/group/list.ts
index cc49edf2..0dea435d 100644
--- a/src/commands/access-control/member/group/list.ts
+++ b/src/commands/access-control/member/group/list.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class ListGroupMembers extends BaseCommand {
     static description = 'List all group members of an iTwin.';
@@ -18,11 +17,8 @@ export default class ListGroupMembers extends BaseCommand {
     ];
   
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin whose group members you want to list.',
-        helpValue: '<string>',
-        required: true,
       }),
     };
   
diff --git a/src/commands/access-control/member/group/update.ts b/src/commands/access-control/member/group/update.ts
index aa2d5694..d394d611 100644
--- a/src/commands/access-control/member/group/update.ts
+++ b/src/commands/access-control/member/group/update.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class UpdateGroupMember extends BaseCommand {
     static description = 'Update the role assignments for a group in an iTwin.';
@@ -24,11 +25,8 @@ export default class UpdateGroupMember extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the groups will be added.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to which the groups will be added.'
       }),
       "role-id": Flags.string({
         description: 'A list of role IDs to assign to the group.',
diff --git a/src/commands/access-control/member/invitations.ts b/src/commands/access-control/member/invitations.ts
index c2211ac7..e9ddfe2d 100644
--- a/src/commands/access-control/member/invitations.ts
+++ b/src/commands/access-control/member/invitations.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class AccessControlMemberInvitations extends BaseCommand {
     static description = "Retrieve the list of pending invitations for an iTwin's members.";
@@ -18,11 +17,8 @@ export default class AccessControlMemberInvitations extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: "The ID of the iTwin whose member invitations you want to retrieve.",
-        helpValue: '<string>',
-        required: true,
       }),
     };
   
diff --git a/src/commands/access-control/member/owner/add.ts b/src/commands/access-control/member/owner/add.ts
index 7c0fbd78..8d1bdff3 100644
--- a/src/commands/access-control/member/owner/add.ts
+++ b/src/commands/access-control/member/owner/add.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class AddOwner extends BaseCommand {
     static description = 'Add a new owner to an iTwin by email.';
@@ -23,11 +24,8 @@ export default class AddOwner extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the owner will be added.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to which the owner will be added.'
       }),
     };
   
diff --git a/src/commands/access-control/member/owner/delete.ts b/src/commands/access-control/member/owner/delete.ts
index 15458535..24653054 100644
--- a/src/commands/access-control/member/owner/delete.ts
+++ b/src/commands/access-control/member/owner/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class DeleteOwner extends BaseCommand {
     static description = 'Remove an owner from an iTwin by their member ID.';
@@ -18,11 +19,8 @@ export default class DeleteOwner extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin from which the owner will be removed.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin from which the owner will be removed.'
       }),
       "member-id": Flags.string({
         description: 'The ID of the owner to be removed.',
diff --git a/src/commands/access-control/member/owner/list.ts b/src/commands/access-control/member/owner/list.ts
index 01889194..6951a0f8 100644
--- a/src/commands/access-control/member/owner/list.ts
+++ b/src/commands/access-control/member/owner/list.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class ListOwners extends BaseCommand {
     static description = 'List all owners of a specific iTwin.';
@@ -18,11 +17,8 @@ export default class ListOwners extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin whose owners you want to list.',
-        helpValue: '<string>',
-        required: true,
       }),
     };
   
diff --git a/src/commands/access-control/member/user/add.ts b/src/commands/access-control/member/user/add.ts
index e97a9426..cbb32166 100644
--- a/src/commands/access-control/member/user/add.ts
+++ b/src/commands/access-control/member/user/add.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 import { addMember } from "../../../../services/access-control-client/models/members.js";
 
 export default class AddUserMembers extends BaseCommand {
@@ -19,11 +20,8 @@ export default class AddUserMembers extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the users will be added.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({      
+        description: 'The ID of the iTwin to which the users will be added.'
       }),
       members: Flags.string({
         description: 'A list of members to add, each with an email and a list of role IDs.',
diff --git a/src/commands/access-control/member/user/delete.ts b/src/commands/access-control/member/user/delete.ts
index 480bafd8..93aa9324 100644
--- a/src/commands/access-control/member/user/delete.ts
+++ b/src/commands/access-control/member/user/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class DeleteUserMember extends BaseCommand {
     static description = 'Remove a user from an iTwin.';
@@ -18,11 +19,8 @@ export default class DeleteUserMember extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the user is a member.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the user is a member.'
       }),
       "member-id": Flags.string({
         description: 'The ID of the user to remove from the iTwin.',
diff --git a/src/commands/access-control/member/user/info.ts b/src/commands/access-control/member/user/info.ts
index 4a6fd887..431735ca 100644
--- a/src/commands/access-control/member/user/info.ts
+++ b/src/commands/access-control/member/user/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class InfoUserMember extends BaseCommand {
     static description = 'Retrieve details about a specific user member in an iTwin.';
@@ -18,11 +19,8 @@ export default class InfoUserMember extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the user is a member.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the user is a member.'
       }),
       "member-id": Flags.string({
         description: 'The ID of the user to retrieve information about.',
diff --git a/src/commands/access-control/member/user/list.ts b/src/commands/access-control/member/user/list.ts
index 31661bd3..6685126f 100644
--- a/src/commands/access-control/member/user/list.ts
+++ b/src/commands/access-control/member/user/list.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class ListUserMembers extends BaseCommand {
     static description = 'Retrieve details about a specific user member in an iTwin.';
@@ -18,11 +17,8 @@ export default class ListUserMembers extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin whose user members you want to list.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin whose user members you want to list.'
       }),
     };
   
diff --git a/src/commands/access-control/member/user/update.ts b/src/commands/access-control/member/user/update.ts
index 4de70a0e..d0097d21 100644
--- a/src/commands/access-control/member/user/update.ts
+++ b/src/commands/access-control/member/user/update.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../../extensions/base-command.js";
+import { CustomFlags } from "../../../../extensions/custom-flags.js";
 
 export default class UpdateUserMember extends BaseCommand {
     static description = 'Update the role assignments for a user in an iTwin.';
@@ -18,11 +19,8 @@ export default class UpdateUserMember extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin where the user is a member.',
-        helpValue: '<string>',
-        required: true,
       }),
       "member-id": Flags.string({
         description: 'The ID of the user whose roles will be updated.',
diff --git a/src/commands/access-control/permissions/me.ts b/src/commands/access-control/permissions/me.ts
index ab7e8ea1..bb1ce7ef 100644
--- a/src/commands/access-control/permissions/me.ts
+++ b/src/commands/access-control/permissions/me.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class MyPermissions extends BaseCommand {
     static description = 'Retrieve a list of your permissions on a specified iTwin.';
@@ -18,11 +17,8 @@ export default class MyPermissions extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin for which the role is being created.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin for which the role is being created.'
       }),
     };
   
diff --git a/src/commands/access-control/role/create.ts b/src/commands/access-control/role/create.ts
index b364d230..f8a3e564 100644
--- a/src/commands/access-control/role/create.ts
+++ b/src/commands/access-control/role/create.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class CreateRole extends BaseCommand {
     static description = 'Create a new role for an iTwin. To assign permissions after creation, use itp access-control role update.';
@@ -24,11 +25,8 @@ export default class CreateRole extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to retrieve permissions.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to retrieve permissions.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/access-control/role/delete.ts b/src/commands/access-control/role/delete.ts
index f220eb74..239cf65b 100644
--- a/src/commands/access-control/role/delete.ts
+++ b/src/commands/access-control/role/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class DeleteRole extends BaseCommand {
     static description = 'Delete an existing role from an iTwin.';
@@ -18,11 +19,8 @@ export default class DeleteRole extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the role exists.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the role exists.'
       }),
       "role-id": Flags.string({
         description: 'The ID of the role to be deleted.',
diff --git a/src/commands/access-control/role/info.ts b/src/commands/access-control/role/info.ts
index daf52f63..0ae2e6e5 100644
--- a/src/commands/access-control/role/info.ts
+++ b/src/commands/access-control/role/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class InfoRole extends BaseCommand {
     static description = 'Retrieve details about a specific role in an iTwin.';
@@ -18,11 +19,8 @@ export default class InfoRole extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin where the role exists.',
-        helpValue: '<string>',
-        required: true,
       }),
       "role-id": Flags.string({
         description: 'The ID of the role to retrieve information about.',
diff --git a/src/commands/access-control/role/list.ts b/src/commands/access-control/role/list.ts
index 76708b0d..20c08890 100644
--- a/src/commands/access-control/role/list.ts
+++ b/src/commands/access-control/role/list.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListRoles extends BaseCommand {
     static description = 'List all roles for a specific iTwin.';
@@ -18,11 +17,8 @@ export default class ListRoles extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
+      "itwin-id": CustomFlags.iTwinIDFlag({
         description: 'The ID of the iTwin whose roles you want to list.',
-        helpValue: '<string>',
-        required: true,
       }),
     };
   
diff --git a/src/commands/access-control/role/update.ts b/src/commands/access-control/role/update.ts
index 3c396c83..0d84762b 100644
--- a/src/commands/access-control/role/update.ts
+++ b/src/commands/access-control/role/update.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class UpdateRole extends BaseCommand {
     static description = 'Update the details of an existing role in an iTwin.';
@@ -28,11 +29,8 @@ export default class UpdateRole extends BaseCommand {
         helpValue: '<string>',
         required: false,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the role exists.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the role exists.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/changed-elements/changesets.ts b/src/commands/changed-elements/changesets.ts
index 2fb10664..b0b6f834 100644
--- a/src/commands/changed-elements/changesets.ts
+++ b/src/commands/changed-elements/changesets.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class GetChangesetStatus extends BaseCommand {
     static description = 'Get the processing status of changesets in an iModel to see which are ready for comparison.';
@@ -26,17 +27,11 @@ export default class GetChangesetStatus extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({ 
-        char: 'm', 
-        description: 'The ID of the iModel.', 
-        helpValue: '<string>',
-        required: true 
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel.'
       }),
-      "itwin-id": Flags.string({ 
-        char: 'i', 
-        description: 'The ID of the iTwin.', 
-        helpValue: '<string>',
-        required: true 
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin.' 
       }),
       skip: Flags.integer({ 
         description: 'Skip a number of changesets in the result.',
diff --git a/src/commands/changed-elements/comparison.ts b/src/commands/changed-elements/comparison.ts
index 83de6bc3..85493820 100644
--- a/src/commands/changed-elements/comparison.ts
+++ b/src/commands/changed-elements/comparison.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ChangedElementsComparison extends BaseCommand {
     static description = 'Compare changes between two changesets in an iModel.';
@@ -32,17 +33,11 @@ export default class ChangedElementsComparison extends BaseCommand {
         helpValue: '<string>',
         required: true 
       }),
-      "imodel-id": Flags.string({ 
-        char: 'm', 
-        description: 'The ID of the iModel to compare changesets for.', 
-        helpValue: '<string>',
-        required: true 
+      "imodel-id": CustomFlags.iModelIDFlag({ 
+        description: 'The ID of the iModel to compare changesets for.'
       }),
-      "itwin-id": Flags.string({ 
-        char: 'i',
-        description: 'The ID of the iTwin associated with the iModel.', 
-        helpValue: '<string>',
-        required: true
+      "itwin-id": CustomFlags.iTwinIDFlag({ 
+        description: 'The ID of the iTwin associated with the iModel.'
       })
     };
   
diff --git a/src/commands/changed-elements/disable.ts b/src/commands/changed-elements/disable.ts
index f53c6eba..cf298e46 100644
--- a/src/commands/changed-elements/disable.ts
+++ b/src/commands/changed-elements/disable.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ChangedElementsDisable extends BaseCommand {
     static description = "Disable change tracking for a specified iModel.";
@@ -18,17 +17,11 @@ export default class ChangedElementsDisable extends BaseCommand {
     ];
 
     static flags = {
-        "imodel-id": Flags.string({ 
-          char: 'm', 
-          description: "The ID of the iModel where change tracking should be disabled.", 
-          helpValue: '<string>',
-          required: true 
+        "imodel-id": CustomFlags.iModelIDFlag({ 
+          description: "The ID of the iModel where change tracking should be disabled."
         }),
-        "itwin-id": Flags.string({ 
-          char: 'i', 
-          description: "The ID of the iTwin associated with the iModel.", 
-          helpValue: '<string>',
-          required: true 
+        "itwin-id": CustomFlags.iTwinIDFlag({ 
+          description: "The ID of the iTwin associated with the iModel."
         }),
     };
   
diff --git a/src/commands/changed-elements/enable.ts b/src/commands/changed-elements/enable.ts
index 7c3c15f0..c072f1ef 100644
--- a/src/commands/changed-elements/enable.ts
+++ b/src/commands/changed-elements/enable.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ChangedElementsEnable extends BaseCommand {
     static description = "Enable change tracking for a specified iModel.";
@@ -18,17 +17,11 @@ export default class ChangedElementsEnable extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({ 
-        char: 'm', 
-        description: "The ID of the iModel where change tracking should be enabled.", 
-        helpValue: '<string>',
-        required: true 
+      "imodel-id": CustomFlags.iModelIDFlag({ 
+        description: "The ID of the iModel where change tracking should be enabled."
       }),
-      "itwin-id": Flags.string({ 
-        char: 'i', 
-        description: "The ID of the iTwin associated with the iModel.", 
-        helpValue: '<string>',
-        required: true 
+      "itwin-id": CustomFlags.iTwinIDFlag({ 
+        description: "The ID of the iTwin associated with the iModel."
       }),
     };
   
diff --git a/src/commands/changed-elements/info.ts b/src/commands/changed-elements/info.ts
index d40170ae..c925e876 100644
--- a/src/commands/changed-elements/info.ts
+++ b/src/commands/changed-elements/info.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ChangedElementsInfo extends BaseCommand {
     static description = "Retrieve change tracking information for a specified iModel.";
@@ -18,16 +17,11 @@ export default class ChangedElementsInfo extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({ 
-        char: 'm', 
-        description: "The ID of the iModel to retrieve tracking information for.", 
-        helpValue: '<string>',
-        required: true }),
-      "itwin-id": Flags.string({ 
-        char: 'i', 
-        description: "The ID of the iTwin associated with the iModel.", 
-        helpValue: '<string>',
-        required: true 
+      "imodel-id": CustomFlags.iModelIDFlag({  
+        description: "The ID of the iModel to retrieve tracking information for."
+      }),
+      "itwin-id": CustomFlags.iTwinIDFlag({ 
+        description: "The ID of the iTwin associated with the iModel."
       }),
     };
   
diff --git a/src/commands/imodel/changeset/info.ts b/src/commands/imodel/changeset/info.ts
index 50e2070a..49ef0181 100644
--- a/src/commands/imodel/changeset/info.ts
+++ b/src/commands/imodel/changeset/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ChangesetInfo extends BaseCommand {
     static description = 'Retrieve details about a specific changeset of an iModel.';
@@ -23,11 +24,8 @@ export default class ChangesetInfo extends BaseCommand {
         helpValue: '<string>',
         required: true,
       }),
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel whose changeset you want to retrieve.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel whose changeset you want to retrieve.'
       }),
     };
   
diff --git a/src/commands/imodel/changeset/list.ts b/src/commands/imodel/changeset/list.ts
index 745d137f..bb7d32a8 100644
--- a/src/commands/imodel/changeset/list.ts
+++ b/src/commands/imodel/changeset/list.ts
@@ -7,6 +7,7 @@ import { Changeset, ChangesetOrderByProperty, OrderBy, OrderByOperator, take, to
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListChangesets extends BaseCommand {
     static description = 'List all changesets for a specific iModel.';
@@ -36,11 +37,8 @@ export default class ListChangesets extends BaseCommand {
         helpValue: '<integer>',
         required: false,
       }),
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel whose changesets you want to list.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel whose changesets you want to list.'
       }),
       "last-index": Flags.integer({
         description: 'List changesets up to a specific index (inclusive).',
diff --git a/src/commands/imodel/connection/create.ts b/src/commands/imodel/connection/create.ts
index be6d203e..d6a12efe 100644
--- a/src/commands/imodel/connection/create.ts
+++ b/src/commands/imodel/connection/create.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 import { authenticationType } from "../../../services/synchronizationClient/models/authentication-type.js";
 import { connectorType } from "../../../services/synchronizationClient/models/connector-type.js";
 import { storageFileCreate } from "../../../services/synchronizationClient/models/storage-file-create.js";
@@ -60,11 +61,8 @@ export default class CreateConnection extends BaseCommand {
       multiple: true,
       required: true
     }),
-    "imodel-id": Flags.string({
-      char: 'm', 
-      description: 'The ID of the iModel.', 
-      helpValue: '<string>',
-      required: true 
+    "imodel-id": CustomFlags.iModelIDFlag({
+      description: 'The ID of the iModel.'
     }),
     name: Flags.string({
       char: 'n',
diff --git a/src/commands/imodel/connection/list.ts b/src/commands/imodel/connection/list.ts
index c06a2313..5c7d7ddc 100644
--- a/src/commands/imodel/connection/list.ts
+++ b/src/commands/imodel/connection/list.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListConnections extends BaseCommand {
     static description = 'List all storage connections for a specific iModel.';
@@ -26,11 +27,8 @@ export default class ListConnections extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({
-        char: 'm', 
-        description: 'The ID of the iModel whose storage connections you want to list.', 
-        helpValue: '<string>',
-        required: true 
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel whose storage connections you want to list.'
       }),
       skip: Flags.integer({
         description: 'The number of changesets to skip.', 
diff --git a/src/commands/imodel/create.ts b/src/commands/imodel/create.ts
index a683b3fa..7515f874 100644
--- a/src/commands/imodel/create.ts
+++ b/src/commands/imodel/create.ts
@@ -7,6 +7,7 @@ import { Extent } from "@itwin/imodels-client-management";
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class CreateIModel extends BaseCommand {
     static description = 'Creates an iModel in an iTwin';
@@ -34,11 +35,8 @@ export default class CreateIModel extends BaseCommand {
         helpValue: '<string>',
         required: false,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin where the iModel should be created.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin where the iModel should be created.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/imodel/delete.ts b/src/commands/imodel/delete.ts
index 8f9ac347..637c8f88 100644
--- a/src/commands/imodel/delete.ts
+++ b/src/commands/imodel/delete.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class DeleteIModel extends BaseCommand {
   static description = 'Delete an existing iModel.';
@@ -18,11 +17,8 @@ export default class DeleteIModel extends BaseCommand {
   ];
 
   static flags = {
-    "imodel-id": Flags.string({
-      char: 'm',
-      description: 'The ID of the iModel to delete.',
-      helpValue: '<string>',
-      required: true,
+    "imodel-id": CustomFlags.iModelIDFlag({
+      description: 'The ID of the iModel to delete.'
     }),
   };
 
diff --git a/src/commands/imodel/info.ts b/src/commands/imodel/info.ts
index 88274a20..4caf9890 100644
--- a/src/commands/imodel/info.ts
+++ b/src/commands/imodel/info.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export class IModelInfo extends BaseCommand {
   static description = 'Retrieve metadata for the specified Model';
@@ -18,11 +17,8 @@ export class IModelInfo extends BaseCommand {
   ];
 
   static flags = {
-    "imodel-id": Flags.string({
-      char: 'm', 
-      description: 'The ID of the iModel to retrieve information for.', 
-      helpValue: '<string>',
-      required: true 
+    "imodel-id": CustomFlags.iModelIDFlag({
+      description: 'The ID of the iModel to retrieve information for.'
     }),
   };
 
diff --git a/src/commands/imodel/list.ts b/src/commands/imodel/list.ts
index 8e8e355b..8731d972 100644
--- a/src/commands/imodel/list.ts
+++ b/src/commands/imodel/list.ts
@@ -7,6 +7,7 @@ import { IModel, IModelOrderByProperty, OrderBy } from "@itwin/imodels-client-ma
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ListIModels extends BaseCommand {
     static description = 'Retrieve a list of iModels';
@@ -31,11 +32,8 @@ export default class ListIModels extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to list iModels for.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to list iModels for.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/imodel/named-version/create.ts b/src/commands/imodel/named-version/create.ts
index e29b7f83..b7f2c6f4 100644
--- a/src/commands/imodel/named-version/create.ts
+++ b/src/commands/imodel/named-version/create.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class CreateNamedVersion extends BaseCommand {
     static description = 'Create a new named version for a specific changeset in an iModel.';
@@ -37,11 +38,8 @@ export default class CreateNamedVersion extends BaseCommand {
         helpValue: '<string>',
         required: false,
       }),
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel where the named version will be created.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel where the named version will be created.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/imodel/named-version/info.ts b/src/commands/imodel/named-version/info.ts
index f069cee9..60fb0b2a 100644
--- a/src/commands/imodel/named-version/info.ts
+++ b/src/commands/imodel/named-version/info.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class NamedVersionInfo extends BaseCommand {
     static description = 'Retrieve details about a specific named version in an iModel.';
@@ -18,11 +19,8 @@ export default class NamedVersionInfo extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel whose named version you want to retrieve.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel whose named version you want to retrieve.'
       }),
       "named-version-id": Flags.string({
         description: 'The ID of the named version.',
diff --git a/src/commands/imodel/named-version/list.ts b/src/commands/imodel/named-version/list.ts
index 2bc1af3a..78eb6579 100644
--- a/src/commands/imodel/named-version/list.ts
+++ b/src/commands/imodel/named-version/list.ts
@@ -7,6 +7,7 @@ import { NamedVersion, NamedVersionOrderByProperty, OrderBy, OrderByOperator } f
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListNamedVersions extends BaseCommand {
     static description = 'List all named versions for a specific iModel.';
@@ -31,11 +32,8 @@ export default class ListNamedVersions extends BaseCommand {
     ];
 
     static flags = {
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel whose named versions you want to list.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel whose named versions you want to list.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/imodel/populate.ts b/src/commands/imodel/populate.ts
index 0f36d167..d9932053 100644
--- a/src/commands/imodel/populate.ts
+++ b/src/commands/imodel/populate.ts
@@ -11,6 +11,7 @@ import fs from "node:fs"
 import path from "node:path"
 
 import BaseCommand from "../../extensions/base-command.js"
+import { CustomFlags } from "../../extensions/custom-flags.js"
 import { authorizationInformation } from "../../services/authorization-client/authorization-type.js"
 import { fileUpload } from "../../services/storage-client/models/file-upload.js"
 import { itemsWithFolderLink } from "../../services/storage-client/models/items-with-folder-link.js"
@@ -76,11 +77,8 @@ export default class PopulateIModel extends BaseCommand {
         multiple: true,
         required: true
       }),
-    "imodel-id": Flags.string({
-        char: 'm', 
-        description: 'The ID of the iModel to populate.', 
-        helpValue: '<string>',
-        required: true,
+    "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel to populate.'
     }),
     "no-wait": Flags.boolean({
         description: 'Do not wait for the synchronization process to complete.',
diff --git a/src/commands/imodel/update.ts b/src/commands/imodel/update.ts
index 8dba068d..ae700799 100644
--- a/src/commands/imodel/update.ts
+++ b/src/commands/imodel/update.ts
@@ -7,6 +7,7 @@ import { Extent } from "@itwin/imodels-client-management";
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class UpdateCommand extends BaseCommand {
     static description = 'Update an iModel in an iTwin';
@@ -30,11 +31,8 @@ export default class UpdateCommand extends BaseCommand {
         helpValue: '<string>',
         required: false,
       }),
-      "imodel-id": Flags.string({
-        char: 'm',
-        description: 'The ID of the iModel to update.',
-        helpValue: '<string>',
-        required: true,
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: 'The ID of the iModel to update.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/imodel/view/cesium-sandcastle.ts b/src/commands/imodel/view/cesium-sandcastle.ts
index e2b74d2e..174144e3 100644
--- a/src/commands/imodel/view/cesium-sandcastle.ts
+++ b/src/commands/imodel/view/cesium-sandcastle.ts
@@ -9,6 +9,7 @@ import open from 'open';
 import { deflate } from "pako";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 import { link, links } from "../../../services/general-models/links.js";
 
 export default class CesiumSandcastle extends BaseCommand {
@@ -35,11 +36,8 @@ export default class CesiumSandcastle extends BaseCommand {
         helpValue: '<string>',
         required: false
       }),
-      "imodel-id": Flags.string({ 
-        char: "m", 
-        description: "iModel id to be viewed in Cesium Sandcastle.",
-        helpValue: '<string>',
-        required: true
+      "imodel-id": CustomFlags.iModelIDFlag({
+        description: "iModel id to be viewed in Cesium Sandcastle."
       }),
       "open": Flags.boolean({
         description: "Open the URL in the browser.",
diff --git a/src/commands/itwin/delete.ts b/src/commands/itwin/delete.ts
index f58a1164..76815937 100644
--- a/src/commands/itwin/delete.ts
+++ b/src/commands/itwin/delete.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class DeleteITwin extends BaseCommand {
     static description = 'Delete an iTwin';
@@ -18,11 +17,8 @@ export default class DeleteITwin extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'iTwin id.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'iTwin id.'
       }),
     };
   
diff --git a/src/commands/itwin/info.ts b/src/commands/itwin/info.ts
index 31bc101c..fdb45a1c 100644
--- a/src/commands/itwin/info.ts
+++ b/src/commands/itwin/info.ts
@@ -3,9 +3,8 @@
 * See LICENSE.md in the project root for license terms and full copyright notice.
 *--------------------------------------------------------------------------------------------*/
 
-import { Flags } from "@oclif/core";
-
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class ITwinInfo extends BaseCommand {
     static description = 'Retrieve metadata for the specified iTwin.';
@@ -18,11 +17,8 @@ export default class ITwinInfo extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to retrieve information about.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to retrieve information about.'
       }),
     };
   
diff --git a/src/commands/itwin/repository/create.ts b/src/commands/itwin/repository/create.ts
index ca518c0d..df8fca87 100644
--- a/src/commands/itwin/repository/create.ts
+++ b/src/commands/itwin/repository/create.ts
@@ -7,6 +7,7 @@ import { RepositoryClass, RepositorySubClass } from "@itwin/itwins-client";
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class CreateRepository extends BaseCommand {
     static description = 'Create a new repository URI for iTwin data.';
@@ -33,11 +34,8 @@ export default class CreateRepository extends BaseCommand {
         options: ['GeographicInformationSystem', 'Construction', 'Subsurface'],
         required: true,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the repository belongs.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to which the repository belongs.'
       }),
       "sub-class": Flags.string({
         description: 'The subClass of your repository.',
diff --git a/src/commands/itwin/repository/delete.ts b/src/commands/itwin/repository/delete.ts
index 5d4c27f5..1a48e06f 100644
--- a/src/commands/itwin/repository/delete.ts
+++ b/src/commands/itwin/repository/delete.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class DeleteRepository extends BaseCommand {
     static description = 'Delete a specified repository from an iTwin.';
@@ -18,11 +19,8 @@ export default class DeleteRepository extends BaseCommand {
     ];
 
     static flags = {
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to which the repository belongs.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to which the repository belongs.'
       }),
       "repository-id": Flags.string({
         description: 'The ID of the repository to delete.',
diff --git a/src/commands/itwin/repository/list.ts b/src/commands/itwin/repository/list.ts
index 09cb5cee..4b533a1a 100644
--- a/src/commands/itwin/repository/list.ts
+++ b/src/commands/itwin/repository/list.ts
@@ -6,6 +6,7 @@
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../../extensions/base-command.js";
+import { CustomFlags } from "../../../extensions/custom-flags.js";
 
 export default class ListRepositories extends BaseCommand {
     static description = 'Retrieve a list of repositories for a specified iTwin.';
@@ -32,11 +33,8 @@ export default class ListRepositories extends BaseCommand {
         options: ["iModels", "RealityData", "Storage", "Forms", "Issues", "SensorData", "GeographicInformationSystem", "Construction", "Subsurface"],
         required: false
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin whose repositories should be retrieved.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin whose repositories should be retrieved.'
       }),
       "sub-class": Flags.string({
         description: 'Specify a subClass of repositories. Only applicable for GeographicInformationSystem class.',
diff --git a/src/commands/itwin/update.ts b/src/commands/itwin/update.ts
index b57f2f1d..e01fcecf 100644
--- a/src/commands/itwin/update.ts
+++ b/src/commands/itwin/update.ts
@@ -7,6 +7,7 @@ import { ITwin } from "@itwin/itwins-client";
 import { Flags } from "@oclif/core";
 
 import BaseCommand from "../../extensions/base-command.js";
+import { CustomFlags } from "../../extensions/custom-flags.js";
 
 export default class UpdateCommand extends BaseCommand {
     static description = 'Update an iTwin';
@@ -37,11 +38,8 @@ export default class UpdateCommand extends BaseCommand {
         helpValue: '<string>',
         required: false,
       }),
-      "itwin-id": Flags.string({
-        char: 'i',
-        description: 'The ID of the iTwin to be updated.',
-        helpValue: '<string>',
-        required: true,
+      "itwin-id": CustomFlags.iTwinIDFlag({
+        description: 'The ID of the iTwin to be updated.'
       }),
       name: Flags.string({
         char: 'n',
diff --git a/src/commands/storage/root-folder.ts b/src/commands/storage/root-folder.ts
index e0907472..499578d7 100644
--- a/src/commands/storage/root-folder.ts
+++ b/src/commands/storage/root-folder.ts
@@ -6,6 +6,7 @@
 import { Flags } from '@oclif/core';
 
 import BaseCommand from '../../extensions/base-command.js';
+import { CustomFlags } from '../../extensions/custom-flags.js';
 
 export default class GetRootFolder extends BaseCommand {
   static description = 'Retrieve the top-level folders and files in an iTwin\'s storage.';
@@ -18,11 +19,8 @@ export default class GetRootFolder extends BaseCommand {
   ];
 
   static flags = {
-    "itwin-id": Flags.string({
-      char: 'i',
-      description: 'The ID of the iTwin whose top-level folders and files you want to retrieve.',
-      helpValue: '<string>',
-      required: true,
+    "itwin-id": CustomFlags.iTwinIDFlag({
+      description: 'The ID of the iTwin whose top-level folders and files you want to retrieve.'
     }),
     skip: Flags.integer({
       description: 'The skip query option requests the number of items in the queried collection that are to be skipped and not included in the result.',
diff --git a/src/extensions/custom-flags.ts b/src/extensions/custom-flags.ts
new file mode 100644
index 00000000..63d69b81
--- /dev/null
+++ b/src/extensions/custom-flags.ts
@@ -0,0 +1,24 @@
+import { Flags } from "@oclif/core";
+
+// eslint-disable-next-line unicorn/no-static-only-class
+export class CustomFlags {
+    static iModelIDFlag = (config : CustomFlagConfig) => Flags.string({
+        char: 'm',
+        description: config.description,
+        env: 'ITP_IMODEL_ID',
+        helpValue: '<string>',
+        required: true
+    });
+
+    static iTwinIDFlag = (config : CustomFlagConfig) => Flags.string({ 
+            char: 'i', 
+            description: config.description,
+            env: 'ITP_ITWIN_ID', 
+            helpValue: '<string>',
+            required: true
+          })
+}
+
+export type CustomFlagConfig = {
+    description: string;
+};
\ No newline at end of file