fix: select email-capable account for Send Email fallback

https://sonarly.com/issue/42767?type=bug

The workflow Send Email step can fail when no account is explicitly selected, because fallback account selection can pick a non-email connected account and then crash the send path.

Fix: Implemented the root-cause fix in EmailComposer fallback selection:

- In `EmailComposerService`, replaced unfiltered “first connected account” fallback with email-capable account selection.
- Added `isEmailCapableConnectedAccount()` to gate fallback candidates to:
  - accounts with a message channel matching account handle, or
  - SMTP-only IMAP/SMTP/CALDAV accounts that actually have SMTP configuration.
- Updated fallback query to include `messageChannels` relation and deterministic ordering (`createdAt ASC`) before choosing first eligible account.
- If no email-capable account exists, now throws a clear `CONNECTED_ACCOUNT_NOT_FOUND` EmailToolException instead of selecting an incompatible account and failing later in compose/send.

This addresses the exact failure mode where empty/default `connectedAccountId` selected a non-mail account and then crashed with missing message channel.

Authored by Sonarly by autonomous analysis (run 48880).

packages/twenty-server/src/engine/core-modules/tool/tools/email-tool/draft-email-tool.ts

@@ -63,6 +63,10 @@ export class DraftEmailTool implements Tool {
       };
     } catch (error) {
       if (error instanceof EmailToolException) {
+        this.logger.warn(
+          `Draft creation failed with a handled email tool error (${error.code}) in workspace ${context.workspaceId}`,
+        );
+
         return {
           success: false,
           message: 'Failed to create draft',
@@ -70,9 +74,11 @@ export class DraftEmailTool implements Tool {
         };
       }
 
-      this.logger.error(`Failed to create draft: ${error}`);
-
       if (isInsufficientPermissionsError(error)) {
+        this.logger.warn(
+          `Draft creation failed due to insufficient permissions in workspace ${context.workspaceId}`,
+        );
+
         return {
           success: false,
           message: 'Failed to create draft due to insufficient permissions',
@@ -82,6 +88,11 @@ export class DraftEmailTool implements Tool {
         };
       }
 
+      this.logger.error(
+        `Failed to create draft in workspace ${context.workspaceId}`,
+        error instanceof Error ? error.stack : undefined,
+      );
+
       return {
         success: false,
         message: 'Failed to create draft',

packages/twenty-server/src/engine/core-modules/tool/tools/email-tool/email-composer.service.ts

@@ -1,4 +1,4 @@
-import { Injectable, Logger } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 
 import { toPlainText } from '@react-email/render';
@@ -39,8 +39,6 @@ type ParentThreadContext = {
 
 @Injectable()
 export class EmailComposerService {
-  private readonly logger = new Logger(EmailComposerService.name);
-
   constructor(
     private readonly globalWorkspaceOrmManager: GlobalWorkspaceOrmManager,
     @InjectRepository(ConnectedAccountEntity)
@@ -87,6 +85,23 @@ export class EmailComposerService {
     );
   }
 
+  private isEmailCapableConnectedAccount(
+    connectedAccount: ConnectedAccountEntity,
+  ): boolean {
+    const isSmtpOnlyAccount =
+      connectedAccount.provider ===
+        ConnectedAccountProvider.IMAP_SMTP_CALDAV &&
+      !isDefined(connectedAccount.connectionParameters?.IMAP);
+
+    if (isSmtpOnlyAccount) {
+      return isDefined(connectedAccount.connectionParameters?.SMTP);
+    }
+
+    return connectedAccount.messageChannels.some(
+      (messageChannel) => messageChannel.handle === connectedAccount.handle,
+    );
+  }
+
   private async getOrThrowFirstConnectedAccountId(
     workspaceId: string,
   ): Promise<string> {
@@ -96,6 +111,12 @@ export class EmailComposerService {
       async () => {
         const allAccounts = await this.connectedAccountRepository.find({
           where: { workspaceId },
+          relations: {
+            messageChannels: true,
+          },
+          order: {
+            createdAt: 'ASC',
+          },
         });
 
         if (!allAccounts || allAccounts.length === 0) {
@@ -105,7 +126,18 @@ export class EmailComposerService {
           );
         }
 
-        return allAccounts[0].id;
+        const firstEmailCapableAccount = allAccounts.find((connectedAccount) =>
+          this.isEmailCapableConnectedAccount(connectedAccount),
+        );
+
+        if (!isDefined(firstEmailCapableAccount)) {
+          throw new EmailToolException(
+            'No email-capable connected accounts found for this workspace',
+            EmailToolExceptionCode.CONNECTED_ACCOUNT_NOT_FOUND,
+          );
+        }
+
+        return firstEmailCapableAccount.id;
       },
       authContext,
     );

packages/twenty-server/src/engine/core-modules/tool/tools/email-tool/send-email-tool.ts

@@ -70,6 +70,10 @@ export class SendEmailTool implements Tool {
       };
     } catch (error) {
       if (error instanceof EmailToolException) {
+        this.logger.warn(
+          `Email send failed with a handled email tool error (${error.code}) in workspace ${context.workspaceId}`,
+        );
+
         return {
           success: false,
           message: 'Failed to send email',
@@ -77,9 +81,11 @@ export class SendEmailTool implements Tool {
         };
       }
 
-      this.logger.error(`Failed to send email: ${error}`);
-
       if (isInsufficientPermissionsError(error)) {
+        this.logger.warn(
+          `Email send failed due to insufficient permissions in workspace ${context.workspaceId}`,
+        );
+
         return {
           success: false,
           message: 'Failed to send email due to insufficient permissions',
@@ -89,6 +95,11 @@ export class SendEmailTool implements Tool {
         };
       }
 
+      this.logger.error(
+        `Failed to send email in workspace ${context.workspaceId}`,
+        error instanceof Error ? error.stack : undefined,
+      );
+
       return {
         success: false,
         message: 'Failed to send email',

packages/twenty-server/src/modules/messaging/message-outbound-manager/resolvers/send-email.resolver.ts

@@ -17,6 +17,7 @@ import { FileEmailAttachmentService } from 'src/engine/core-modules/file/file-em
 import { ResolverValidationPipe } from 'src/engine/core-modules/graphql/pipes/resolver-validation.pipe';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { EmailComposerService } from 'src/engine/core-modules/tool/tools/email-tool/email-composer.service';
+import { EmailToolException } from 'src/engine/core-modules/tool/tools/email-tool/exceptions/email-tool.exception';
 import { AuthUserWorkspaceId } from 'src/engine/decorators/auth/auth-user-workspace-id.decorator';
 import { AuthWorkspace } from 'src/engine/decorators/auth/auth-workspace.decorator';
 import { SettingsPermissionGuard } from 'src/engine/guards/settings-permission.guard';
@@ -107,7 +108,21 @@ export class SendEmailResolver {
         throw error;
       }
 
-      this.logger.error(`Failed to send email: ${error}`);
+      if (error instanceof EmailToolException) {
+        this.logger.warn(
+          `Send email mutation failed with a handled email tool error (${error.code}) in workspace ${workspace.id}`,
+        );
+
+        return {
+          success: false,
+          error: error.message,
+        };
+      }
+
+      this.logger.error(
+        `Failed to send email in workspace ${workspace.id}`,
+        error instanceof Error ? error.stack : undefined,
+      );
 
       return {
         success: false,