diff --git a/toolkits/google/arcade_google/tools/constants.py b/toolkits/google/arcade_google/tools/constants.py
new file mode 100644
index 00000000..2ef97c93
--- /dev/null
+++ b/toolkits/google/arcade_google/tools/constants.py
@@ -0,0 +1,18 @@
+import os
+
+from arcade_google.tools.models import GmailReplyToWhom
+
+# The default reply in Gmail is to only the sender. Since Gmail also offers the possibility of
+# changing the default to 'reply to all', we support both options through an env variable.
+# https://support.google.com/mail/answer/6585?hl=en&sjid=15399867888091633568-SA#null
+try:
+    GMAIL_DEFAULT_REPLY_TO = GmailReplyToWhom(
+        # Values accepted are defined in the arcade_google.tools.models.GmailReplyToWhom Enum
+        os.getenv("ARCADE_GMAIL_DEFAULT_REPLY_TO", GmailReplyToWhom.ONLY_THE_SENDER.value).lower()
+    )
+except ValueError as e:
+    raise ValueError(
+        "Invalid value for ARCADE_GMAIL_DEFAULT_REPLY_TO: "
+        f"'{os.getenv('ARCADE_GMAIL_DEFAULT_REPLY_TO')}'. Expected one of "
+        f"{list(GmailReplyToWhom.__members__.keys())}"
+    ) from e
diff --git a/toolkits/google/arcade_google/tools/exceptions.py b/toolkits/google/arcade_google/tools/exceptions.py
new file mode 100644
index 00000000..88937f1f
--- /dev/null
+++ b/toolkits/google/arcade_google/tools/exceptions.py
@@ -0,0 +1,43 @@
+class GoogleToolError(Exception):
+    """Base exception for Google tool errors."""
+
+    def __init__(self, message: str, developer_message: str | None = None):
+        self.message = message
+        self.developer_message = developer_message
+        super().__init__(self.message)
+
+    def __str__(self) -> str:
+        base_message = self.message
+        if self.developer_message:
+            return f"{base_message} (Developer: {self.developer_message})"
+        return base_message
+
+
+class GoogleServiceError(GoogleToolError):
+    """Raised when there's an error building or using the Google service."""
+
+    pass
+
+
+class GmailToolError(GoogleToolError):
+    """Raised when there's an error in the Gmail tools."""
+
+    pass
+
+
+class GoogleCalendarToolError(GoogleToolError):
+    """Raised when there's an error in the Google Calendar tools."""
+
+    pass
+
+
+class GoogleDriveToolError(GoogleToolError):
+    """Raised when there's an error in the Google Drive tools."""
+
+    pass
+
+
+class GoogleDocsToolError(GoogleToolError):
+    """Raised when there's an error in the Google Docs tools."""
+
+    pass
diff --git a/toolkits/google/arcade_google/tools/gmail.py b/toolkits/google/arcade_google/tools/gmail.py
index ccf846e2..25b7d2b2 100644
--- a/toolkits/google/arcade_google/tools/gmail.py
+++ b/toolkits/google/arcade_google/tools/gmail.py
@@ -1,24 +1,30 @@
 import base64
-from email.message import EmailMessage
 from email.mime.text import MIMEText
 from typing import Annotated, Any, Optional
 
 from arcade.sdk import ToolContext, tool
 from arcade.sdk.auth import Google
 from arcade.sdk.errors import RetryableToolError
-from google.oauth2.credentials import Credentials
-from googleapiclient.discovery import build
+from googleapiclient.errors import HttpError
 
+from arcade_google.tools.constants import GMAIL_DEFAULT_REPLY_TO
+from arcade_google.tools.exceptions import GmailToolError
+from arcade_google.tools.models import GmailAction, GmailReplyToWhom
 from arcade_google.tools.utils import (
     DateRange,
-    build_query_string,
+    _build_gmail_service,
+    build_email_message,
+    build_gmail_query_string,
+    build_reply_recipients,
     fetch_messages,
     get_draft_url,
+    get_email_details,
     get_email_in_trash_url,
+    get_label_ids,
     get_sent_email_url,
     parse_draft_email,
-    parse_email,
-    process_email_messages,
+    parse_multipart_email,
+    parse_plain_text_email,
     remove_none_values,
 )
 
@@ -40,37 +46,12 @@ async def send_email(
     """
     Send an email using the Gmail API.
     """
+    service = _build_gmail_service(context)
+    email = build_email_message(recipient, subject, body, cc, bcc)
 
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
-
-    message = EmailMessage()
-    message.set_content(body)
-    message["To"] = recipient
-    message["Subject"] = subject
-    if cc:
-        message["Cc"] = ", ".join(cc)
-    if bcc:
-        message["Bcc"] = ", ".join(bcc)
-
-    # Encode the message in base64
-    encoded_message = base64.urlsafe_b64encode(message.as_bytes()).decode()
-
-    # Create the email
-    email = {"raw": encoded_message}
-
-    # Send the email
     sent_message = service.users().messages().send(userId="me", body=email).execute()
 
-    email = parse_email(sent_message)
+    email = parse_plain_text_email(sent_message)
     email["url"] = get_sent_email_url(sent_message["id"])
     return email
 
@@ -87,21 +68,79 @@ async def send_draft_email(
     Send a draft email using the Gmail API.
     """
 
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     # Send the draft email
     sent_message = service.users().drafts().send(userId="me", body={"id": email_id}).execute()
 
-    email = parse_email(sent_message)
+    email = parse_plain_text_email(sent_message)
+    email["url"] = get_sent_email_url(sent_message["id"])
+    return email
+
+
+# Note: in the Gmail UI, a user can customize the recipient and cc fields before replying.
+# We decided not to support this feature, since we'd need a way for LLMs to tell apart between
+# adding or removing recipients/cc, or replacing with an entirely new list of addresses,
+# which would make the tool more complex to call.
+@tool(
+    requires_auth=Google(
+        scopes=["https://www.googleapis.com/auth/gmail.send"],
+    )
+)
+async def reply_to_email(
+    context: ToolContext,
+    body: Annotated[str, "The body of the email"],
+    reply_to_message_id: Annotated[str, "The ID of the message to reply to"],
+    reply_to_whom: Annotated[
+        GmailReplyToWhom,
+        "Whether to reply to every recipient (including cc) or only to the original sender. "
+        f"Defaults to '{GMAIL_DEFAULT_REPLY_TO}'.",
+    ] = GMAIL_DEFAULT_REPLY_TO,
+    bcc: Annotated[Optional[list[str]], "BCC recipients of the email"] = None,
+) -> Annotated[dict, "A dictionary containing the sent email details"]:
+    """
+    Send a reply to an email message.
+    """
+    if isinstance(reply_to_whom, str):
+        reply_to_whom = GmailReplyToWhom(reply_to_whom)
+
+    service = _build_gmail_service(context)
+
+    current_user = service.users().getProfile(userId="me").execute()
+
+    try:
+        replying_to_email = (
+            service.users().messages().get(userId="me", id=reply_to_message_id).execute()
+        )
+    except HttpError as e:
+        raise RetryableToolError(
+            message=f"Could not retrieve the message with id {reply_to_message_id}.",
+            developer_message=(
+                f"Could not retrieve the message with id {reply_to_message_id}. "
+                f"Reason: '{e.reason}'. Error details: '{e.error_details}'"
+            ),
+        ) from e
+
+    replying_to_email = parse_multipart_email(replying_to_email)
+
+    recipients = build_reply_recipients(
+        replying_to_email, current_user["emailAddress"], reply_to_whom
+    )
+
+    email = build_email_message(
+        recipient=recipients,
+        subject=f"Re: {replying_to_email['subject']}",
+        body=body,
+        cc=None
+        if reply_to_whom == GmailReplyToWhom.ONLY_THE_SENDER
+        else replying_to_email["cc"].split(","),
+        bcc=bcc,
+        replying_to=replying_to_email,
+    )
+
+    sent_message = service.users().messages().send(userId="me", body=email).execute()
+
+    email = parse_plain_text_email(sent_message)
     email["url"] = get_sent_email_url(sent_message["id"])
     return email
 
@@ -124,29 +163,11 @@ async def write_draft_email(
     Compose a new email draft using the Gmail API.
     """
     # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
-    message = MIMEText(body)
-    message["to"] = recipient
-    message["subject"] = subject
-    if cc:
-        message["Cc"] = ", ".join(cc)
-    if bcc:
-        message["Bcc"] = ", ".join(bcc)
-
-    # Encode the message in base64
-    raw_message = base64.urlsafe_b64encode(message.as_bytes()).decode()
-
-    # Create the draft
-    draft = {"message": {"raw": raw_message}}
+    draft = {
+        "message": build_email_message(recipient, subject, body, cc, bcc, action=GmailAction.DRAFT)
+    }
 
     draft_message = service.users().drafts().create(userId="me", body=draft).execute()
     email = parse_draft_email(draft_message)
@@ -154,6 +175,76 @@ async def write_draft_email(
     return email
 
 
+# Note: in the Gmail UI, a user can customize the recipient and cc fields before replying.
+# We decided not to support this feature, since we'd need a way for LLMs to tell apart between
+# adding or removing recipients/cc, or replacing with an entirely new list of addresses,
+# which would make the tool more complex to call.
+@tool(
+    requires_auth=Google(
+        scopes=["https://www.googleapis.com/auth/gmail.compose"],
+    )
+)
+async def write_draft_reply_email(
+    context: ToolContext,
+    body: Annotated[str, "The body of the draft reply email"],
+    reply_to_message_id: Annotated[str, "The Gmail message ID of the message to draft a reply to"],
+    reply_to_whom: Annotated[
+        GmailReplyToWhom,
+        "Whether to reply to every recipient (including cc) or only to the original sender. "
+        f"Defaults to '{GMAIL_DEFAULT_REPLY_TO}'.",
+    ] = GMAIL_DEFAULT_REPLY_TO,
+    bcc: Annotated[Optional[list[str]], "BCC recipients of the draft reply email"] = None,
+) -> Annotated[dict, "A dictionary containing the created draft reply email details"]:
+    """
+    Compose a draft reply to an email message.
+    """
+    if isinstance(reply_to_whom, str):
+        reply_to_whom = GmailReplyToWhom(reply_to_whom)
+
+    service = _build_gmail_service(context)
+
+    current_user = service.users().getProfile(userId="me").execute()
+
+    try:
+        replying_to_email = (
+            service.users().messages().get(userId="me", id=reply_to_message_id).execute()
+        )
+    except HttpError as e:
+        raise RetryableToolError(
+            message="Could not retrieve the message to respond to.",
+            developer_message=(
+                "Could not retrieve the message to respond to. "
+                f"Reason: '{e.reason}'. Error details: '{e.error_details}'"
+            ),
+        )
+
+    replying_to_email = parse_multipart_email(replying_to_email)
+
+    recipients = build_reply_recipients(
+        replying_to_email, current_user["emailAddress"], reply_to_whom
+    )
+
+    draft_message = {
+        "message": build_email_message(
+            recipient=recipients,
+            subject=f"Re: {replying_to_email['subject']}",
+            body=body,
+            cc=None
+            if reply_to_whom == GmailReplyToWhom.ONLY_THE_SENDER
+            else replying_to_email["cc"].split(","),
+            bcc=bcc,
+            replying_to=replying_to_email,
+            action=GmailAction.DRAFT,
+        ),
+    }
+
+    draft = service.users().drafts().create(userId="me", body=draft_message).execute()
+
+    email = parse_draft_email(draft)
+    email["url"] = get_draft_url(draft["id"])
+    return email
+
+
 @tool(
     requires_auth=Google(
         scopes=["https://www.googleapis.com/auth/gmail.compose"],
@@ -171,17 +262,7 @@ async def update_draft_email(
     """
     Update an existing email draft using the Gmail API.
     """
-
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     message = MIMEText(body)
     message["to"] = recipient
@@ -203,6 +284,7 @@ async def update_draft_email(
 
     email = parse_draft_email(updated_draft_message)
     email["url"] = get_draft_url(updated_draft_message["id"])
+
     return email
 
 
@@ -218,17 +300,7 @@ async def delete_draft_email(
     """
     Delete a draft email using the Gmail API.
     """
-
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     # Delete the draft
     service.users().drafts().delete(userId="me", id=draft_email_id).execute()
@@ -248,21 +320,12 @@ async def trash_email(
     Move an email to the trash folder using the Gmail API.
     """
 
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     # Trash the email
     trashed_email = service.users().messages().trash(userId="me", id=email_id).execute()
 
-    email = parse_email(trashed_email)
+    email = parse_plain_text_email(trashed_email)
     email["url"] = get_email_in_trash_url(trashed_email["id"])
     return email
 
@@ -280,16 +343,7 @@ async def list_draft_emails(
     """
     Lists draft emails in the user's draft mailbox using the Gmail API.
     """
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     listed_drafts = service.users().drafts().list(userId="me").execute()
 
@@ -306,12 +360,13 @@ async def list_draft_emails(
             if draft_details:
                 emails.append(draft_details)
         except Exception as e:
-            print(f"Error reading draft email {draft_id}: {e}")
+            raise GmailToolError(
+                message=f"Error reading draft email {draft_id}.", developer_message=str(e)
+            )
 
     return {"emails": emails}
 
 
-# Email Search Tools
 @tool(
     requires_auth=Google(
         scopes=["https://www.googleapis.com/auth/gmail.readonly"],
@@ -324,39 +379,58 @@ async def list_emails_by_header(
     subject: Annotated[Optional[str], "Words to find in the subject of the email"] = None,
     body: Annotated[Optional[str], "Words to find in the body of the email"] = None,
     date_range: Annotated[Optional[DateRange], "The date range of the email"] = None,
-    limit: Annotated[int, "The maximum number of emails to return"] = 25,
+    label: Annotated[Optional[str], "The label name to filter by"] = None,
+    max_results: Annotated[int, "The maximum number of emails to return"] = 25,
 ) -> Annotated[
     dict, "A dictionary containing a list of email details matching the search criteria"
 ]:
     """
     Search for emails by header using the Gmail API.
-    At least one of the following parameters MUST be provided: sender, recipient, subject, body.
+
+    At least one of the following parameters MUST be provided: sender, recipient,
+    subject, date_range, label, or body.
     """
-    if not any([sender, recipient, subject, body]):
+    service = _build_gmail_service(context)
+    # Ensure at least one search parameter is provided
+    if not any([sender, recipient, subject, body, label, date_range]):
         raise RetryableToolError(
-            message="At least one of sender, recipient, subject, or body must be provided.",
+            message=(
+                "At least one of sender, recipient, subject, body, label, query, "
+                "or date_range must be provided."
+            ),
             developer_message=(
-                "At least one of sender, recipient, subject, or body must be provided."
+                "At least one of sender, recipient, subject, body, label, query, "
+                "or date_range must be provided."
             ),
         )
 
-    query = build_query_string(sender, recipient, subject, body, date_range)
+    # Check if label is valid
+    if label:
+        label_ids = get_label_ids(service, [label])
 
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
-    messages = fetch_messages(service, query, limit)
+        if not label_ids:
+            labels = service.users().labels().list(userId="me").execute().get("labels", [])
+            label_names = [label["name"] for label in labels]
+            raise RetryableToolError(
+                message=f"Invalid label: {label}",
+                developer_message=f"Invalid label: {label}",
+                additional_prompt_content=f"List of valid labels: {label_names}",
+            )
 
+    # Build a Gmail-style query string based on the filters
+    query = build_gmail_query_string(sender, recipient, subject, body, date_range, label)
+
+    # Fetch matching messages. This fetches message metadata from Gmail
+    messages = fetch_messages(service, query, max_results)
+
+    # If no messages found, return an empty list
     if not messages:
         return {"emails": []}
 
-    emails = process_email_messages(service, messages)
+    # Process each message into a structured email object
+    emails = get_email_details(service, messages)
+
+    # Return the list of emails in a dictionary with key "emails"
     return {"emails": emails}
 
 
@@ -372,16 +446,7 @@ async def list_emails(
     """
     Read emails from a Gmail account and extract plain text content.
     """
-    # Set up the Gmail API client
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     messages = service.users().messages().list(userId="me").execute().get("messages", [])
 
@@ -392,12 +457,13 @@ async def list_emails(
     for msg in messages[:n_emails]:
         try:
             email_data = service.users().messages().get(userId="me", id=msg["id"]).execute()
-            email_details = parse_email(email_data)
+            email_details = parse_plain_text_email(email_data)
             if email_details:
                 emails.append(email_details)
         except Exception as e:
-            print(f"Error reading email {msg['id']}: {e}")
-
+            raise GmailToolError(
+                message=f"Error reading email {msg['id']}.", developer_message=str(e)
+            )
     return {"emails": emails}
 
 
@@ -421,18 +487,10 @@ async def search_threads(
     date_range: Annotated[Optional[DateRange], "The date range of the email"] = None,
 ) -> Annotated[dict, "A dictionary containing a list of thread details"]:
     """Search for threads in the user's mailbox"""
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
 
     query = (
-        build_query_string(sender, recipient, subject, body, date_range)
+        build_gmail_query_string(sender, recipient, subject, body, date_range)
         if any([sender, recipient, subject, body, date_range])
         else None
     )
@@ -506,16 +564,101 @@ async def get_thread(
     }
     params = remove_none_values(params)
 
-    service = build(
-        "gmail",
-        "v1",
-        credentials=Credentials(
-            context.authorization.token
-            if context.authorization and context.authorization.token
-            else ""
-        ),
-    )
+    service = _build_gmail_service(context)
+
     thread = service.users().threads().get(**params).execute()
-    thread["messages"] = [parse_email(message) for message in thread.get("messages", [])]
+    thread["messages"] = [parse_plain_text_email(message) for message in thread.get("messages", [])]
 
     return dict(thread)
+
+
+@tool(
+    requires_auth=Google(
+        scopes=["https://www.googleapis.com/auth/gmail.modify"],
+    )
+)
+async def change_email_labels(
+    context: ToolContext,
+    email_id: Annotated[str, "The ID of the email to modify labels for"],
+    labels_to_add: Annotated[list[str], "List of label names to add"],
+    labels_to_remove: Annotated[list[str], "List of label names to remove"],
+) -> Annotated[dict, "List of labels that were added, removed, and not found"]:
+    """
+    Add and remove labels from an email using the Gmail API.
+    """
+    service = _build_gmail_service(context)
+
+    add_labels = get_label_ids(service, labels_to_add)
+    remove_labels = get_label_ids(service, labels_to_remove)
+
+    invalid_labels = (
+        set(labels_to_add + labels_to_remove) - set(add_labels.keys()) - set(remove_labels.keys())
+    )
+
+    if invalid_labels:
+        # prepare the list of valid labels
+        labels = service.users().labels().list(userId="me").execute().get("labels", [])
+        label_names = [label["name"] for label in labels]
+
+        # raise a retryable error with the list of valid labels
+        raise RetryableToolError(
+            message=f"Invalid labels: {invalid_labels}",
+            developer_message=f"Invalid labels: {invalid_labels}",
+            additional_prompt_content=f"List of valid labels: {label_names}",
+        )
+
+    # Prepare the modification body with label IDs.
+    body = {
+        "addLabelIds": list(add_labels.values()),
+        "removeLabelIds": list(remove_labels.values()),
+    }
+
+    try:  # Modify the email labels.
+        service.users().messages().modify(userId="me", id=email_id, body=body).execute()
+
+    except Exception as e:
+        raise GmailToolError(
+            message=f"Error modifying labels for email {email_id}", developer_message=str(e)
+        )
+
+    # Confirmation JSON with lists for added and removed labels.
+    confirmation = {
+        "addedLabels": list(add_labels.keys()),
+        "removedLabels": list(remove_labels.keys()),
+    }
+
+    return {"confirmation": dict(confirmation)}
+
+
+@tool(
+    requires_auth=Google(
+        scopes=["https://www.googleapis.com/auth/gmail.readonly"],
+    )
+)
+async def list_labels(
+    context: ToolContext,
+) -> Annotated[dict, "A dictionary containing a list of label details"]:
+    """List all the labels in the user's mailbox."""
+
+    service = _build_gmail_service(context)
+
+    labels = service.users().labels().list(userId="me").execute().get("labels", [])
+
+    return {"labels": labels}
+
+
+@tool(
+    requires_auth=Google(
+        scopes=["https://www.googleapis.com/auth/gmail.labels"],
+    )
+)
+async def create_label(
+    context: ToolContext,
+    label_name: Annotated[str, "The name of the label to create"],
+) -> Annotated[dict, "The details of the created label"]:
+    """Create a new label in the user's mailbox."""
+
+    service = _build_gmail_service(context)
+    label = service.users().labels().create(userId="me", body={"name": label_name}).execute()
+
+    return {"label": label}
diff --git a/toolkits/google/arcade_google/tools/models.py b/toolkits/google/arcade_google/tools/models.py
index 11540e2d..41431c21 100644
--- a/toolkits/google/arcade_google/tools/models.py
+++ b/toolkits/google/arcade_google/tools/models.py
@@ -342,3 +342,16 @@ class OrderBy(str, Enum):
         # The last time the file was viewed by the user (descending)
         "viewedByMeTime desc"
     )
+
+
+# ---------------------------------------------------------------------------- #
+# Google Gmail Models and Enums
+# ---------------------------------------------------------------------------- #
+class GmailReplyToWhom(str, Enum):
+    EVERY_RECIPIENT = "every_recipient"
+    ONLY_THE_SENDER = "only_the_sender"
+
+
+class GmailAction(str, Enum):
+    SEND = "send"
+    DRAFT = "draft"
diff --git a/toolkits/google/arcade_google/tools/utils.py b/toolkits/google/arcade_google/tools/utils.py
index c9bd42e6..330590ef 100644
--- a/toolkits/google/arcade_google/tools/utils.py
+++ b/toolkits/google/arcade_google/tools/utils.py
@@ -1,16 +1,28 @@
+import logging
 import re
-from base64 import urlsafe_b64decode
+from base64 import urlsafe_b64decode, urlsafe_b64encode
 from datetime import datetime, timedelta
+from email.message import EmailMessage
+from email.mime.text import MIMEText
 from enum import Enum
-from typing import Any, Optional
+from typing import Any, Optional, Union
 from zoneinfo import ZoneInfo
 
+from arcade.sdk import ToolContext
 from bs4 import BeautifulSoup
 from google.oauth2.credentials import Credentials
 from googleapiclient.discovery import Resource, build
-from googleapiclient.errors import HttpError
 
-from arcade_google.tools.models import Day, TimeSlot
+from arcade_google.tools.exceptions import GmailToolError, GoogleServiceError
+from arcade_google.tools.models import Day, GmailAction, GmailReplyToWhom, TimeSlot
+
+## Set up basic configuration for logging to the console with DEBUG level and a specific format.
+logging.basicConfig(
+    level=logging.DEBUG,
+    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
+)
+
+logger = logging.getLogger(__name__)
 
 
 def parse_datetime(datetime_str: str, time_zone: str) -> datetime:
@@ -73,21 +85,77 @@ class DateRange(Enum):
         return result + comparison_date.strftime("%Y/%m/%d")
 
 
-def process_email_messages(service: Any, messages: list[dict[str, Any]]) -> list[dict[str, Any]]:
-    emails = []
-    for msg in messages:
-        try:
-            email_data = service.users().messages().get(userId="me", id=msg["id"]).execute()
-            email_details = parse_email(email_data)
-            emails += [email_details] if email_details else []
-        except HttpError as e:
-            print(f"Error reading email {msg['id']}: {e}")
-    return emails
+def build_email_message(
+    recipient: str,
+    subject: str,
+    body: str,
+    cc: Optional[list[str]] = None,
+    bcc: Optional[list[str]] = None,
+    replying_to: Optional[dict[str, Any]] = None,
+    action: GmailAction = GmailAction.SEND,
+) -> dict[str, Any]:
+    if replying_to:
+        body = build_reply_body(body, replying_to)
+
+    message: Union[EmailMessage, MIMEText]
+
+    if action == GmailAction.SEND:
+        message = EmailMessage()
+        message.set_content(body)
+    elif action == GmailAction.DRAFT:
+        message = MIMEText(body)
+
+    message["To"] = recipient
+    message["Subject"] = subject
+
+    if cc:
+        message["Cc"] = ",".join(cc)
+    if bcc:
+        message["Bcc"] = ",".join(bcc)
+    if replying_to:
+        message["In-Reply-To"] = replying_to["header_message_id"]
+        message["References"] = f"{replying_to['header_message_id']}, {replying_to['references']}"
+
+    encoded_message = urlsafe_b64encode(message.as_bytes()).decode()
+
+    data = {"raw": encoded_message}
+
+    if replying_to:
+        data["threadId"] = replying_to["thread_id"]
+
+    return data
 
 
-def parse_email(email_data: dict[str, Any]) -> dict[str, Any]:
+def build_reply_body(body: str, replying_to: dict[str, Any]) -> str:
+    attribution = f"On {replying_to['date']}, {replying_to['from']} wrote:"
+    lines = replying_to["plain_text_body"].split("\n")
+    quoted_plain = "\n".join([f"> {line}" for line in lines])
+    return f"{body}\n\n{attribution}\n\n{quoted_plain}"
+
+
+def build_reply_recipients(
+    replying_to: dict[str, Any], current_user_email_address: str, reply_to_whom: GmailReplyToWhom
+) -> str:
+    if reply_to_whom == GmailReplyToWhom.ONLY_THE_SENDER:
+        recipients = [replying_to["from"]]
+    elif reply_to_whom == GmailReplyToWhom.EVERY_RECIPIENT:
+        recipients = [replying_to["from"], *replying_to["to"].split(",")]
+    else:
+        raise ValueError(f"Unsupported reply_to_whom value: {reply_to_whom}")
+
+    recipients = [
+        email_address.strip()
+        for email_address in recipients
+        if email_address.strip().lower() != current_user_email_address.lower().strip()
+    ]
+
+    return ", ".join(recipients)
+
+
+def parse_plain_text_email(email_data: dict[str, Any]) -> dict[str, Any]:
     """
     Parse email data and extract relevant information.
+    Only returns the plain text body.
 
     Args:
         email_data (Dict[str, Any]): Raw email data from Gmail API.
@@ -95,23 +163,71 @@ def parse_email(email_data: dict[str, Any]) -> dict[str, Any]:
     Returns:
         Optional[Dict[str, str]]: Parsed email details or None if parsing fails.
     """
-    try:
-        payload = email_data.get("payload", {})
-        headers = {d["name"].lower(): d["value"] for d in payload.get("headers", [])}
+    payload = email_data.get("payload", {})
+    headers = {d["name"].lower(): d["value"] for d in payload.get("headers", [])}
 
-        body_data = _get_email_body(payload)
+    body_data = _get_email_plain_text_body(payload)
 
-        return {
-            "id": email_data.get("id", ""),
-            "thread_id": email_data.get("threadId", ""),
-            "from": headers.get("from", ""),
-            "date": headers.get("date", ""),
-            "subject": headers.get("subject", ""),
-            "body": _clean_email_body(body_data) if body_data else "",
-        }
-    except Exception as e:
-        print(f"Error parsing email {email_data.get('id', 'unknown')}: {e}")
-        return email_data
+    email_details = {
+        "id": email_data.get("id", ""),
+        "thread_id": email_data.get("threadId", ""),
+        "label_ids": email_data.get("labelIds", []),
+        "history_id": email_data.get("historyId", ""),
+        "snippet": email_data.get("snippet", ""),
+        "to": headers.get("to", ""),
+        "cc": headers.get("cc", ""),
+        "from": headers.get("from", ""),
+        "reply_to": headers.get("reply-to", ""),
+        "in_reply_to": headers.get("in-reply-to", ""),
+        "references": headers.get("references", ""),
+        "header_message_id": headers.get("message-id", ""),
+        "date": headers.get("date", ""),
+        "subject": headers.get("subject", ""),
+        "body": body_data or "",
+    }
+
+    return email_details
+
+
+def parse_multipart_email(email_data: dict[str, Any]) -> dict[str, Any]:
+    """
+    Parse email data and extract relevant information.
+    Returns the plain text and HTML body along with the images.
+
+    Args:
+        email_data (Dict[str, Any]): Raw email data from Gmail API.
+
+    Returns:
+        Optional[Dict[str, Any]]: Parsed email details or None if parsing fails.
+    """
+
+    payload = email_data.get("payload", {})
+    headers = {d["name"].lower(): d["value"] for d in payload.get("headers", [])}
+
+    # Extract different parts of the email
+    plain_text_body = _get_email_plain_text_body(payload)
+    html_body = _get_email_html_body(payload)
+
+    email_details = {
+        "id": email_data.get("id", ""),
+        "thread_id": email_data.get("threadId", ""),
+        "label_ids": email_data.get("labelIds", []),
+        "history_id": email_data.get("historyId", ""),
+        "snippet": email_data.get("snippet", ""),
+        "to": headers.get("to", ""),
+        "cc": headers.get("cc", ""),
+        "from": headers.get("from", ""),
+        "reply_to": headers.get("reply-to", ""),
+        "in_reply_to": headers.get("in-reply-to", ""),
+        "references": headers.get("references", ""),
+        "header_message_id": headers.get("message-id", ""),
+        "date": headers.get("date", ""),
+        "subject": headers.get("subject", ""),
+        "plain_text_body": plain_text_body or _clean_email_body(html_body),
+        "html_body": html_body or "",
+    }
+
+    return email_details
 
 
 def parse_draft_email(draft_email_data: dict[str, Any]) -> dict[str, str]:
@@ -124,24 +240,20 @@ def parse_draft_email(draft_email_data: dict[str, Any]) -> dict[str, str]:
     Returns:
         Optional[Dict[str, str]]: Parsed draft email details or None if parsing fails.
     """
-    try:
-        message = draft_email_data.get("message", {})
-        payload = message.get("payload", {})
-        headers = {d["name"].lower(): d["value"] for d in payload.get("headers", [])}
+    message = draft_email_data.get("message", {})
+    payload = message.get("payload", {})
+    headers = {d["name"].lower(): d["value"] for d in payload.get("headers", [])}
 
-        body_data = _get_email_body(payload)
+    body_data = _get_email_plain_text_body(payload)
 
-        return {
-            "id": draft_email_data.get("id", ""),
-            "thread_id": draft_email_data.get("threadId", ""),
-            "from": headers.get("from", ""),
-            "date": headers.get("internaldate", ""),
-            "subject": headers.get("subject", ""),
-            "body": _clean_email_body(body_data) if body_data else "",
-        }
-    except Exception as e:
-        print(f"Error parsing draft email {draft_email_data.get('id', 'unknown')}: {e}")
-        return draft_email_data
+    return {
+        "id": draft_email_data.get("id", ""),
+        "thread_id": draft_email_data.get("threadId", ""),
+        "from": headers.get("from", ""),
+        "date": headers.get("internaldate", ""),
+        "subject": headers.get("subject", ""),
+        "body": _clean_email_body(body_data) if body_data else "",
+    }
 
 
 def get_draft_url(draft_id: str) -> str:
@@ -152,13 +264,143 @@ def get_sent_email_url(sent_email_id: str) -> str:
     return f"https://mail.google.com/mail/u/0/#sent/{sent_email_id}"
 
 
+def get_email_details(service: Any, messages: list[dict[str, Any]]) -> list[dict[str, Any]]:
+    """
+    Retrieves full message data for each message ID in the given list and extracts email details.
+
+    :param service: Authenticated Gmail API service instance.
+    :param messages: A list of dictionaries, each representing a message with an 'id' key.
+    :return: A list of dictionaries, each containing parsed email details.
+    """
+
+    emails = []
+    for msg in messages:
+        try:
+            # Fetch the full message data from Gmail using the message ID
+            email_data = service.users().messages().get(userId="me", id=msg["id"]).execute()
+            # Parse the raw email data into a structured form
+            email_details = parse_plain_text_email(email_data)
+            # Only add the details if parsing was successful
+            if email_details:
+                emails.append(email_details)
+        except Exception as e:
+            # Log any errors encountered while trying to fetch or parse a message
+            raise GmailToolError(
+                message=f"Error reading email {msg['id']}.", developer_message=str(e)
+            )
+    return emails
+
+
 def get_email_in_trash_url(email_id: str) -> str:
     return f"https://mail.google.com/mail/u/0/#trash/{email_id}"
 
 
-def _get_email_body(payload: dict[str, Any]) -> Optional[str]:
+def _build_gmail_service(context: ToolContext) -> Any:
     """
-    Extract email body from payload.
+    Private helper function to build and return the Gmail service client.
+
+    Args:
+        context (ToolContext): The context containing authorization details.
+
+    Returns:
+        googleapiclient.discovery.Resource: An authorized Gmail API service instance.
+    """
+    try:
+        credentials = Credentials(
+            context.authorization.token
+            if context.authorization and context.authorization.token
+            else ""
+        )
+    except Exception as e:
+        raise GoogleServiceError(message="Failed to build Gmail service.", developer_message=str(e))
+
+    return build("gmail", "v1", credentials=credentials)
+
+
+def _extract_plain_body(parts: list) -> Optional[str]:
+    """
+    Recursively extract the email body from parts, handling both plain text and HTML.
+
+    Args:
+        parts (List[Dict[str, Any]]): List of email parts.
+
+    Returns:
+        Optional[str]: Decoded and cleaned email body or None if not found.
+    """
+    for part in parts:
+        mime_type = part.get("mimeType")
+
+        if mime_type == "text/plain" and "data" in part.get("body", {}):
+            return urlsafe_b64decode(part["body"]["data"]).decode()
+
+        elif mime_type.startswith("multipart/"):
+            subparts = part.get("parts", [])
+            body = _extract_plain_body(subparts)
+            if body:
+                return body
+
+    return _extract_html_body(parts)
+
+
+def _extract_html_body(parts: list) -> Optional[str]:
+    """
+    Recursively extract the email body from parts, handling only HTML.
+
+    Args:
+        parts (List[Dict[str, Any]]): List of email parts.
+
+    Returns:
+        Optional[str]: Decoded and cleaned email body or None if not found.
+    """
+    for part in parts:
+        mime_type = part.get("mimeType")
+
+        if mime_type == "text/html" and "data" in part.get("body", {}):
+            html_content = urlsafe_b64decode(part["body"]["data"]).decode()
+            return html_content
+
+        elif mime_type.startswith("multipart/"):
+            subparts = part.get("parts", [])
+            body = _extract_html_body(subparts)
+            if body:
+                return body
+
+    return None
+
+
+def _get_email_images(payload: dict[str, Any]) -> Optional[list[str]]:
+    """
+    Extract the email images from an email payload.
+
+    Args:
+        payload (Dict[str, Any]): Email payload data.
+
+    Returns:
+        Optional[List[str]]: List of decoded image contents or None if none found.
+    """
+    images = []
+    for part in payload.get("parts", []):
+        mime_type = part.get("mimeType")
+
+        if mime_type.startswith("image/") and "data" in part.get("body", {}):
+            image_content = part["body"]["data"]
+            images.append(image_content)
+
+        elif mime_type.startswith("multipart/"):
+            subparts = part.get("parts", [])
+            subimages = _get_email_images(subparts)
+            if subimages:
+                images.extend(subimages)
+
+    if images:
+        return images
+
+    return None
+
+
+def _get_email_plain_text_body(payload: dict[str, Any]) -> Optional[str]:
+    """
+    Extract email body from payload, handling 'multipart/alternative' parts.
 
     Args:
         payload (Dict[str, Any]): Email payload data.
@@ -166,17 +408,33 @@ def _get_email_body(payload: dict[str, Any]) -> Optional[str]:
     Returns:
         Optional[str]: Decoded email body or None if not found.
     """
+    # Direct body extraction
+    if "body" in payload and payload["body"].get("data"):
+        return _clean_email_body(urlsafe_b64decode(payload["body"]["data"]).decode())
+
+    # Handle multipart and alternative parts
+    return _clean_email_body(_extract_plain_body(payload.get("parts", [])))
+
+
+def _get_email_html_body(payload: dict[str, Any]) -> Optional[str]:
+    """
+    Extract email html body from payload, handling 'multipart/alternative' parts.
+
+    Args:
+        payload (Dict[str, Any]): Email payload data.
+
+    Returns:
+        Optional[str]: Decoded email body or None if not found.
+    """
+    # Direct body extraction
     if "body" in payload and payload["body"].get("data"):
         return urlsafe_b64decode(payload["body"]["data"]).decode()
 
-    for part in payload.get("parts", []):
-        if part.get("mimeType") == "text/plain" and "data" in part["body"]:
-            return urlsafe_b64decode(part["body"]["data"]).decode()
-
-    return None
+    # Handle multipart and alternative parts
+    return _extract_html_body(payload.get("parts", []))
 
 
-def _clean_email_body(body: str) -> str:
+def _clean_email_body(body: Optional[str]) -> str:
     """
     Remove HTML tags and clean up email body text while preserving most content.
 
@@ -186,6 +444,9 @@ def _clean_email_body(body: str) -> str:
     Returns:
         str: Cleaned email body text.
     """
+    if not body:
+        return ""
+
     try:
         # Remove HTML tags using BeautifulSoup
         soup = BeautifulSoup(body, "html.parser")
@@ -195,8 +456,8 @@ def _clean_email_body(body: str) -> str:
         cleaned_text = _clean_text(text)
 
         return cleaned_text.strip()
-    except Exception as e:
-        print(f"Error cleaning email body: {e}")
+    except Exception:
+        logger.exception("Error cleaning email body")
         return body
 
 
@@ -240,12 +501,13 @@ def _update_datetime(day: Day | None, time: TimeSlot | None, time_zone: str) ->
     return None
 
 
-def build_query_string(
-    sender: str | None,
-    recipient: str | None,
-    subject: str | None,
-    body: str | None,
-    date_range: DateRange | None,
+def build_gmail_query_string(
+    sender: str | None = None,
+    recipient: str | None = None,
+    subject: str | None = None,
+    body: str | None = None,
+    date_range: DateRange | None = None,
+    label: str | None = None,
 ) -> str:
     """Helper function to build a query string
     for Gmail list_emails_by_header and search_threads tools.
@@ -261,9 +523,43 @@ def build_query_string(
         query.append(body)
     if date_range:
         query.append(date_range.to_date_query())
+    if label:
+        query.append(f"label:{label}")
     return " ".join(query)
 
 
+def get_label_ids(service: Any, label_names: list[str]) -> dict[str, str]:
+    """
+    Retrieve label IDs for given label names.
+    Returns a dictionary mapping label names to their IDs.
+
+    Args:
+        service: Authenticated Gmail API service instance.
+        label_names: List of label names to retrieve IDs for.
+
+    Returns:
+        A dictionary mapping found label names to their corresponding IDs.
+    """
+    try:
+        # Fetch all existing labels from Gmail
+        labels = service.users().labels().list(userId="me").execute().get("labels", [])
+    except Exception as e:
+        raise GmailToolError(message="Failed to list labels.", developer_message=str(e)) from e
+
+    # Create a mapping from label names to their IDs
+    label_id_map = {label["name"]: label["id"] for label in labels}
+
+    found_labels = {}
+    for name in label_names:
+        label_id = label_id_map.get(name)
+        if label_id:
+            found_labels[name] = label_id
+        else:
+            logger.warning(f"Label '{name}' does not exist")
+
+    return found_labels
+
+
 def fetch_messages(service: Any, query_string: str, limit: int) -> list[dict[str, Any]]:
     """
     Helper function to fetch messages from Gmail API for the list_emails_by_header tool.
diff --git a/toolkits/google/evals/eval_google_gmail.py b/toolkits/google/evals/eval_google_gmail.py
index 93f62c58..a15db333 100644
--- a/toolkits/google/evals/eval_google_gmail.py
+++ b/toolkits/google/evals/eval_google_gmail.py
@@ -1,3 +1,5 @@
+import json
+
 from arcade.sdk import ToolCatalog
 from arcade.sdk.eval import (
     BinaryCritic,
@@ -11,10 +13,14 @@ from arcade.sdk.eval import (
 import arcade_google
 from arcade_google.tools.gmail import (
     get_thread,
+    list_emails_by_header,
     list_threads,
+    reply_to_email,
     search_threads,
     send_email,
+    write_draft_reply_email,
 )
+from arcade_google.tools.models import GmailReplyToWhom
 from arcade_google.tools.utils import DateRange
 
 # Evaluation rubric
@@ -159,3 +165,267 @@ def gmail_eval_suite() -> EvalSuite:
     )
 
     return suite
+
+
+@tool_eval()
+def gmail_reply_eval_suite() -> EvalSuite:
+    """Create an evaluation suite for Gmail reply tools."""
+    suite = EvalSuite(
+        name="Gmail Reply Tools Evaluation",
+        system_message="You are an AI assistant that can send and manage emails using the provided tools.",
+        catalog=catalog,
+        rubric=rubric,
+    )
+
+    email_history = [
+        {"role": "user", "content": "get the latest emails I received from johndoe@gmail.com"},
+        {
+            "role": "assistant",
+            "content": "",
+            "tool_calls": [
+                {
+                    "id": "call_jowMD7aB9sVPClOfvNof7Llu",
+                    "type": "function",
+                    "function": {
+                        "name": "Google_ListEmailsByHeader",
+                        "arguments": json.dumps({
+                            "sender": "johndoe@gmail.com",
+                            "max_results": 5,
+                        }),
+                    },
+                }
+            ],
+        },
+        {
+            "role": "tool",
+            "content": json.dumps({
+                "emails": [
+                    {
+                        "body": "test 1",
+                        "cc": "",
+                        "date": "Tue, 11 Feb 2025 11:33:08 -0300",
+                        "from": "John Doe <johndoe@gmail.com>",
+                        "header_message_id": "<cierty475cty7245yxq@mail.gmail.com>",
+                        "history_id": "123456",
+                        "id": "q34759q435nv",
+                        "in_reply_to": "",
+                        "label_ids": ["INBOX"],
+                        "references": "",
+                        "reply_to": "",
+                        "snippet": "test 1",
+                        "subject": "test 1",
+                        "thread_id": "345y6v3596",
+                        "to": "myself@gmail.com",
+                    },
+                    {
+                        "body": "test 2",
+                        "cc": "",
+                        "date": "Mon, 20 Jan 2025 13:04:42 -0800",
+                        "from": "John Doe <johndoe@gmail.com>",
+                        "header_message_id": "<28745ytvw8745ct4@mail.gmail.com>",
+                        "history_id": "3456758",
+                        "id": "9475tvy24578yx",
+                        "in_reply_to": "",
+                        "label_ids": [],
+                        "references": "",
+                        "reply_to": "",
+                        "snippet": "test 2",
+                        "subject": "test 2",
+                        "thread_id": "249576v3496",
+                        "to": "myself@gmail.com",
+                    },
+                ]
+            }),
+            "tool_call_id": "call_jowMD7aB9sVPClOfvNof7Llu",
+            "name": "Google_ListEmailsByHeader",
+        },
+        {
+            "role": "assistant",
+            "content": "Here are the latest emails you received from johndoe@gmail.com:\n\n1. **Subject**: test 1\n   - **Date**: Tue, 11 Feb 2025 11:33:08 -0300\n   - **Snippet**: test 1\n\n2. **Subject**: test 2\n   - **Date**: Mon, 20 Jan 2025 13:04:42 -0800\n   - **Snippet**: test 2\n\nIf you need further details from any specific email, let me know!",
+        },
+    ]
+
+    suite.add_case(
+        name="Reply to an email",
+        user_message="Reply to the email from johndoe@example.com about 'test 2' saying 'tested and working well'",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=reply_to_email,
+                args={
+                    "reply_to_message_id": "9475tvy24578yx",
+                    "body": "tested and working well",
+                    "reply_to_whom": GmailReplyToWhom.ONLY_THE_SENDER.value,
+                },
+            )
+        ],
+        critics=[
+            SimilarityCritic(critic_field="subject", weight=1 / 7),
+            SimilarityCritic(critic_field="body", weight=1 / 7),
+            BinaryCritic(critic_field="recipient", weight=1 / 7),
+            BinaryCritic(critic_field="cc", weight=1 / 7),
+            BinaryCritic(critic_field="bcc", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_whom", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_message_id", weight=1 / 7),
+        ],
+        additional_messages=email_history,
+    )
+
+    suite.add_case(
+        name="Reply to an email with every recipient",
+        user_message="Reply to every recipient in the email from johndoe@example.com about 'test 2' saying 'tested and working well'",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=reply_to_email,
+                args={
+                    "reply_to_message_id": "9475tvy24578yx",
+                    "body": "tested and working well",
+                    "reply_to_whom": GmailReplyToWhom.EVERY_RECIPIENT.value,
+                },
+            )
+        ],
+        critics=[
+            SimilarityCritic(critic_field="subject", weight=1 / 7),
+            SimilarityCritic(critic_field="body", weight=1 / 7),
+            BinaryCritic(critic_field="recipient", weight=1 / 7),
+            BinaryCritic(critic_field="cc", weight=1 / 7),
+            BinaryCritic(critic_field="bcc", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_whom", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_message_id", weight=1 / 7),
+        ],
+        additional_messages=email_history,
+    )
+
+    suite.add_case(
+        name="Reply to an email with bcc",
+        user_message="Reply to the email from johndoe@example.com about 'test 2' saying 'tested and working well' and send it to janedoe@example.com as bcc as well",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=reply_to_email,
+                args={
+                    "reply_to_message_id": "9475tvy24578yx",
+                    "body": "tested and working well",
+                    "bcc": ["janedoe@example.com"],
+                    "reply_to_whom": GmailReplyToWhom.ONLY_THE_SENDER.value,
+                },
+            )
+        ],
+        critics=[
+            SimilarityCritic(critic_field="subject", weight=1 / 7),
+            SimilarityCritic(critic_field="body", weight=1 / 7),
+            BinaryCritic(critic_field="recipient", weight=1 / 7),
+            BinaryCritic(critic_field="cc", weight=1 / 7),
+            BinaryCritic(critic_field="bcc", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_whom", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_message_id", weight=1 / 7),
+        ],
+        additional_messages=email_history,
+    )
+
+    suite.add_case(
+        name="Write draft reply",
+        user_message="Write a draft reply to the email from johndoe@example.com about 'test 2' saying 'tested and working well'",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=write_draft_reply_email,
+                args={
+                    "reply_to_message_id": "9475tvy24578yx",
+                    "body": "tested and working well",
+                    "reply_to_whom": GmailReplyToWhom.ONLY_THE_SENDER.value,
+                },
+            )
+        ],
+        critics=[
+            SimilarityCritic(critic_field="subject", weight=1 / 7),
+            SimilarityCritic(critic_field="body", weight=1 / 7),
+            BinaryCritic(critic_field="recipient", weight=1 / 7),
+            BinaryCritic(critic_field="cc", weight=1 / 7),
+            BinaryCritic(critic_field="bcc", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_message_id", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_whom", weight=1 / 7),
+        ],
+        additional_messages=email_history,
+    )
+
+    suite.add_case(
+        name="Write draft reply to every recipient",
+        user_message="Write a draft reply to every recipient in the email from johndoe@example.com about 'test 2' saying 'tested and working well'",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=write_draft_reply_email,
+                args={
+                    "reply_to_message_id": "9475tvy24578yx",
+                    "body": "tested and working well",
+                    "reply_to_whom": GmailReplyToWhom.EVERY_RECIPIENT.value,
+                },
+            )
+        ],
+        critics=[
+            SimilarityCritic(critic_field="subject", weight=1 / 7),
+            SimilarityCritic(critic_field="body", weight=1 / 7),
+            BinaryCritic(critic_field="recipient", weight=1 / 7),
+            BinaryCritic(critic_field="cc", weight=1 / 7),
+            BinaryCritic(critic_field="bcc", weight=1 / 7),
+            BinaryCritic(critic_field="reply_to_whom", weight=0.125),
+            BinaryCritic(critic_field="reply_to_message_id", weight=1 / 7),
+        ],
+        additional_messages=email_history,
+    )
+
+    return suite
+
+
+@tool_eval()
+def gmail_list_emails_by_header_eval_suite() -> EvalSuite:
+    """Create an evaluation suite for Gmail tools."""
+    suite = EvalSuite(
+        name="Gmail list_emails_by_header tool evaluation",
+        system_message="You are an AI assistant that can send and manage emails using the provided tools.",
+        catalog=catalog,
+        rubric=rubric,
+    )
+
+    suite.add_case(
+        name="List emails by header using date-range",
+        user_message="List all emails from johndoe@example.com to janedoe@example.com about 'Arcade AI' from yesterday",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=list_emails_by_header,
+                args={
+                    "sender": "johndoe@example.com",
+                    "recipient": "janedoe@example.com",
+                    "subject": "Arcade AI",
+                    "date_range": DateRange.YESTERDAY.value,
+                },
+            )
+        ],
+        critics=[
+            BinaryCritic(critic_field="sender", weight=1 / 4),
+            BinaryCritic(critic_field="recipient", weight=1 / 4),
+            SimilarityCritic(critic_field="subject", weight=1 / 4),
+            BinaryCritic(critic_field="date_range", weight=1 / 4),
+        ],
+    )
+
+    suite.add_case(
+        name="List emails by header using date-range",
+        user_message="List all emails from johndoe@example.com to janedoe@example.com about 'Arcade AI' from the last month",
+        expected_tool_calls=[
+            ExpectedToolCall(
+                func=list_emails_by_header,
+                args={
+                    "sender": "johndoe@example.com",
+                    "recipient": "janedoe@example.com",
+                    "subject": "Arcade AI",
+                    "date_range": DateRange.LAST_MONTH.value,
+                },
+            )
+        ],
+        critics=[
+            BinaryCritic(critic_field="sender", weight=1 / 4),
+            BinaryCritic(critic_field="recipient", weight=1 / 4),
+            SimilarityCritic(critic_field="subject", weight=1 / 4),
+            BinaryCritic(critic_field="date_range", weight=1 / 4),
+        ],
+    )
+
+    return suite
diff --git a/toolkits/google/tests/test_gmail.py b/toolkits/google/tests/test_gmail.py
index 85f64a6d..95850705 100644
--- a/toolkits/google/tests/test_gmail.py
+++ b/toolkits/google/tests/test_gmail.py
@@ -1,3 +1,5 @@
+from base64 import urlsafe_b64encode
+from email.message import EmailMessage
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -12,6 +14,7 @@ from arcade_google.tools.gmail import (
     list_emails,
     list_emails_by_header,
     list_threads,
+    reply_to_email,
     search_threads,
     send_draft_email,
     send_email,
@@ -19,7 +22,13 @@ from arcade_google.tools.gmail import (
     update_draft_email,
     write_draft_email,
 )
-from arcade_google.tools.utils import parse_draft_email, parse_email
+from arcade_google.tools.models import GmailReplyToWhom
+from arcade_google.tools.utils import (
+    build_reply_body,
+    parse_draft_email,
+    parse_multipart_email,
+    parse_plain_text_email,
+)
 
 
 @pytest.fixture
@@ -29,7 +38,7 @@ def mock_context():
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_send_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -64,7 +73,7 @@ async def test_send_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_write_draft_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -99,7 +108,7 @@ async def test_write_draft_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_update_draft_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -136,7 +145,7 @@ async def test_update_draft_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_send_draft_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -161,7 +170,7 @@ async def test_send_draft_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_delete_draft_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -183,7 +192,7 @@ async def test_delete_draft_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 @patch("arcade_google.tools.gmail.parse_draft_email")
 async def test_get_draft_emails(mock_parse_draft_email, mock_build, mock_context):
     # Setup test data
@@ -234,7 +243,7 @@ async def test_get_draft_emails(mock_parse_draft_email, mock_build, mock_context
     # Mock the response from the Gmail get drafts API
     mock_service.users().drafts().get().execute.return_value = mock_drafts_get_response
 
-    # Mock the parse_email function since parse_email doesn't accept object of type MagicMock
+    # Mock the parse_draft_email function since parse_draft_email doesn't accept object of type MagicMock
     mock_parse_draft_email.return_value = parse_draft_email(mock_drafts_get_response)
 
     # Test happy path
@@ -256,9 +265,9 @@ async def test_get_draft_emails(mock_parse_draft_email, mock_build, mock_context
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
-@patch("arcade_google.tools.gmail.parse_email")
-async def test_search_emails_by_header(mock_parse_email, mock_build, mock_context):
+@patch("arcade_google.tools.utils.build")
+@patch("arcade_google.tools.gmail.parse_plain_text_email")
+async def test_search_emails_by_header(mock_parse_plain_text_email, mock_build, mock_context):
     # Setup test data
     mock_messages_list_response = {
         "messages": [
@@ -307,11 +316,13 @@ async def test_search_emails_by_header(mock_parse_email, mock_build, mock_contex
     # Mock the response from the Gmail get messages API
     mock_service.users().messages().get().execute.return_value = mock_messages_get_response
 
-    # Mock the parse_email function since parse_email doesn't accept object of type MagicMock
-    mock_parse_email.return_value = parse_email(mock_messages_get_response)
+    # Mock the parse_plain_text_email function since parse_plain_text_email doesn't accept object of type MagicMock
+    mock_parse_plain_text_email.return_value = parse_plain_text_email(mock_messages_get_response)
 
     # Test happy path
-    result = await list_emails_by_header(context=mock_context, sender="noreply@github.com", limit=2)
+    result = await list_emails_by_header(
+        context=mock_context, sender="noreply@github.com", max_results=2
+    )
 
     assert isinstance(result, dict)
     assert "emails" in result
@@ -325,13 +336,15 @@ async def test_search_emails_by_header(mock_parse_email, mock_build, mock_contex
     )
 
     with pytest.raises(ToolExecutionError):
-        await list_emails_by_header(context=mock_context, sender="noreply@github.com", limit=2)
+        await list_emails_by_header(
+            context=mock_context, sender="noreply@github.com", max_results=2
+        )
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
-@patch("arcade_google.tools.gmail.parse_email")
-async def test_get_emails(mock_parse_email, mock_build, mock_context):
+@patch("arcade_google.tools.utils.build")
+@patch("arcade_google.tools.gmail.parse_plain_text_email")
+async def test_get_emails(mock_parse_plain_text_email, mock_build, mock_context):
     # Setup test data
     mock_messages_list_response = {
         "messages": [
@@ -379,8 +392,8 @@ async def test_get_emails(mock_parse_email, mock_build, mock_context):
     # Mock the Gmail get messages API
     mock_service.users().messages().get().execute.return_value = mock_messages_get_response
 
-    # Mock the parse_email function since parse_email doesn't accept object of type MagicMock
-    mock_parse_email.return_value = parse_email(mock_messages_get_response)
+    # Mock the parse_plain_text_email function since parse_plain_text_email doesn't accept object of type MagicMock
+    mock_parse_plain_text_email.return_value = parse_plain_text_email(mock_messages_get_response)
 
     # Test happy path
     result = await list_emails(context=mock_context, n_emails=1)
@@ -404,7 +417,7 @@ async def test_get_emails(mock_parse_email, mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_trash_email(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -430,7 +443,7 @@ async def test_trash_email(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_search_threads(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -482,7 +495,7 @@ async def test_search_threads(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_list_threads(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -532,7 +545,7 @@ async def test_list_threads(mock_build, mock_context):
 
 
 @pytest.mark.asyncio
-@patch("arcade_google.tools.gmail.build")
+@patch("arcade_google.tools.utils.build")
 async def test_get_thread(mock_build, mock_context):
     mock_service = MagicMock()
     mock_build.return_value = mock_service
@@ -579,3 +592,360 @@ async def test_get_thread(mock_build, mock_context):
             context=mock_context,
             thread_id="invalid_thread",
         )
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "reply_to_whom, expected_to, expected_cc",
+    [
+        (
+            GmailReplyToWhom.EVERY_RECIPIENT,
+            "sender@example.com, to1@example.com, to2@example.com",
+            "cc1@example.com, cc2@example.com",
+        ),
+        (
+            GmailReplyToWhom.ONLY_THE_SENDER,
+            "sender@example.com",
+            "",
+        ),
+    ],
+)
+@patch("arcade_google.tools.utils.build")
+async def test_reply_to_email(mock_build, reply_to_whom, expected_to, expected_cc, mock_context):
+    mock_service = MagicMock()
+    mock_build.return_value = mock_service
+
+    original_message = {
+        "id": "id123456",
+        "threadId": "thread123456",
+        "payload": {
+            "headers": [
+                {"name": "Message-ID", "value": "id123456"},
+                {"name": "Subject", "value": "test"},
+                {"name": "From", "value": "sender@example.com"},
+                {"name": "To", "value": "to1@example.com, to2@example.com, test@example.com"},
+                {"name": "Cc", "value": "cc1@example.com, cc2@example.com"},
+                {"name": "References", "value": "thread123456"},
+            ],
+        },
+    }
+
+    mock_service.users().getProfile().execute.return_value = {"emailAddress": "test@example.com"}
+    mock_service.users().messages().get().execute.return_value = original_message
+
+    result = await reply_to_email(
+        context=mock_context,
+        body="test",
+        reply_to_message_id="id123456",
+        reply_to_whom=reply_to_whom,
+    )
+
+    assert isinstance(result, dict)
+    assert "url" in result
+
+    replying_to = parse_multipart_email(original_message)
+    expected_body = build_reply_body("test", replying_to)
+
+    expected_message = EmailMessage()
+    expected_message.set_content(expected_body)
+    expected_message["To"] = expected_to
+    expected_message["Subject"] = "Re: test"
+    if expected_cc:
+        expected_message["Cc"] = expected_cc
+    expected_message["In-Reply-To"] = "id123456"
+    expected_message["References"] = "id123456, thread123456"
+
+    mock_service.users().messages().send.assert_called_once_with(
+        userId="me",
+        body={
+            "raw": urlsafe_b64encode(expected_message.as_bytes()).decode(),
+            "threadId": "thread123456",
+        },
+    )
+
+
+def test_parse_multipart_email_full():
+    """
+    Test parsing a multipart email with both plain text and HTML bodies.
+    """
+    email_data = {
+        "id": "email123",
+        "threadId": "thread123",
+        "labelIds": ["INBOX", "UNREAD"],
+        "historyId": "history123",
+        "snippet": "This is a test email.",
+        "payload": {
+            "headers": [
+                {"name": "To", "value": "recipient@example.com"},
+                {"name": "From", "value": "sender@example.com"},
+                {"name": "Subject", "value": "Test Email"},
+                {"name": "Date", "value": "Mon, 1 Jan 2024 10:00:00 -0000"},
+            ],
+            "body": {"size": 100, "data": "VGhpcyBpcyBhIHRlc3QgZW1haWwu"},
+        },
+    }
+
+    with (
+        patch("arcade_google.tools.utils._get_email_plain_text_body") as mock_plain,
+        patch("arcade_google.tools.utils._get_email_html_body") as mock_html,
+        patch("arcade_google.tools.utils._clean_email_body") as mock_clean,
+    ):
+        # Mock the helper functions
+        mock_plain.return_value = "This is a test email."
+        mock_html.return_value = "<p>This is a test email.</p>"
+        mock_clean.return_value = "This is a test email."
+
+        result = parse_multipart_email(email_data)
+
+        assert result["id"] == "email123"
+        assert result["thread_id"] == "thread123"
+        assert result["label_ids"] == ["INBOX", "UNREAD"]
+        assert result["snippet"] == "This is a test email."
+        assert result["to"] == "recipient@example.com"
+        assert result["from"] == "sender@example.com"
+        assert result["subject"] == "Test Email"
+        assert result["date"] == "Mon, 1 Jan 2024 10:00:00 -0000"
+        assert result["plain_text_body"] == "This is a test email."
+        assert result["html_body"] == "<p>This is a test email.</p>"
+
+
+def test_parse_multipart_email_plain_only():
+    """
+    Test parsing an email with only a plain text body.
+    """
+    email_data = {
+        "id": "email456",
+        "threadId": "thread456",
+        "labelIds": ["INBOX"],
+        "historyId": "history456",
+        "snippet": "Plain text only email.",
+        "payload": {
+            "headers": [
+                {"name": "To", "value": "recipient2@example.com"},
+                {"name": "From", "value": "sender2@example.com"},
+                {"name": "Subject", "value": "Plain Text Email"},
+                {"name": "Date", "value": "Tue, 2 Feb 2024 11:00:00 -0000"},
+            ],
+            "body": {"size": 150, "data": "UGxhaW4gdGV4dCBvbmx5IGVtYWlsLg=="},
+        },
+    }
+
+    with (
+        patch("arcade_google.tools.utils._get_email_plain_text_body") as mock_plain,
+        patch("arcade_google.tools.utils._get_email_html_body") as mock_html,
+        patch("arcade_google.tools.utils._clean_email_body") as mock_clean,
+    ):
+        # Mock the helper functions
+        mock_plain.return_value = "Plain text only email."
+        mock_html.return_value = None
+        mock_clean.return_value = "Plain text only email."
+
+        result = parse_multipart_email(email_data)
+
+        assert result["id"] == "email456"
+        assert result["thread_id"] == "thread456"
+        assert result["label_ids"] == ["INBOX"]
+        assert result["snippet"] == "Plain text only email."
+        assert result["to"] == "recipient2@example.com"
+        assert result["from"] == "sender2@example.com"
+        assert result["subject"] == "Plain Text Email"
+        assert result["date"] == "Tue, 2 Feb 2024 11:00:00 -0000"
+        assert result["plain_text_body"] == "Plain text only email."
+        assert result["html_body"] == ""
+
+
+def test_parse_multipart_email_html_only():
+    """
+    Test parsing an email with only an HTML body.
+    """
+    email_data = {
+        "id": "email789",
+        "threadId": "thread789",
+        "labelIds": ["SENT"],
+        "historyId": "history789",
+        "snippet": "HTML only email.",
+        "payload": {
+            "headers": [
+                {"name": "To", "value": "recipient3@example.com"},
+                {"name": "From", "value": "sender3@example.com"},
+                {"name": "Subject", "value": "HTML Email"},
+                {"name": "Date", "value": "Wed, 3 Mar 2024 12:00:00 -0000"},
+            ],
+            "body": {"size": 200, "data": "PGh0bWw+VGhpcyBpcyBIVE1MIGVtYWlsLjwvaHRtbD4="},
+        },
+    }
+
+    with (
+        patch("arcade_google.tools.utils._get_email_plain_text_body") as mock_plain,
+        patch("arcade_google.tools.utils._get_email_html_body") as mock_html,
+        patch("arcade_google.tools.utils._clean_email_body") as mock_clean,
+    ):
+        # Mock the helper functions
+        mock_plain.return_value = None
+        mock_html.return_value = "<html>This is HTML email.</html>"
+        mock_clean.return_value = "This is HTML email."
+
+        result = parse_multipart_email(email_data)
+
+        assert result["id"] == "email789"
+        assert result["thread_id"] == "thread789"
+        assert result["label_ids"] == ["SENT"]
+        assert result["snippet"] == "HTML only email."
+        assert result["to"] == "recipient3@example.com"
+        assert result["from"] == "sender3@example.com"
+        assert result["subject"] == "HTML Email"
+        assert result["date"] == "Wed, 3 Mar 2024 12:00:00 -0000"
+        assert result["plain_text_body"] == "This is HTML email."
+        assert result["html_body"] == "<html>This is HTML email.</html>"
+
+
+def test_parse_multipart_email_missing_payload():
+    """
+    Test parsing an email with missing payload.
+    """
+    email_data = {
+        "id": "email000",
+        "threadId": "thread000",
+        "labelIds": ["INBOX"],
+        "historyId": "history000",
+        "snippet": "Missing payload email.",
+        # 'payload' key is missing
+    }
+
+    result = parse_multipart_email(email_data)
+
+    # Since payload is missing, headers and bodies should be default or empty
+    assert result["id"] == "email000"
+    assert result["thread_id"] == "thread000"
+    assert result["label_ids"] == ["INBOX"]
+    assert result["snippet"] == "Missing payload email."
+    assert result["to"] == ""
+    assert result["from"] == ""
+    assert result["subject"] == ""
+    assert result["date"] == ""
+    assert result["plain_text_body"] == ""
+    assert result["html_body"] == ""
+
+
+def test_parse_multipart_email_missing_headers():
+    """
+    Test parsing an email with missing headers in the payload.
+    """
+    email_data = {
+        "id": "email111",
+        "threadId": "thread111",
+        "labelIds": ["INBOX"],
+        "historyId": "history111",
+        "snippet": "Missing headers email.",
+        "payload": {
+            # 'headers' key is missing
+            "body": {"size": 100, "data": "VGltZWw="}
+        },
+    }
+
+    with (
+        patch("arcade_google.tools.utils._get_email_plain_text_body") as mock_plain,
+        patch("arcade_google.tools.utils._get_email_html_body") as mock_html,
+        patch("arcade_google.tools.utils._clean_email_body") as mock_clean,
+    ):
+        # Mock the helper functions
+        mock_plain.return_value = "Timeel"
+        mock_html.return_value = "<p>Timeel</p>"
+        mock_clean.return_value = "Timeel"
+
+        result = parse_multipart_email(email_data)
+
+    assert result["id"] == "email111"
+    assert result["thread_id"] == "thread111"
+    assert result["label_ids"] == ["INBOX"]
+    assert result["snippet"] == "Missing headers email."
+    assert result["to"] == ""
+    assert result["from"] == ""
+    assert result["subject"] == ""
+    assert result["date"] == ""
+    assert result["plain_text_body"] == "Timeel"
+    assert result["html_body"] == "<p>Timeel</p>"
+
+
+def test_parse_multipart_email_missing_fields():
+    """
+    Test parsing an email with some missing fields in headers.
+    """
+    email_data = {
+        "id": "email222",
+        "threadId": "thread222",
+        "labelIds": ["INBOX"],
+        "historyId": "history222",
+        "snippet": "Missing some headers.",
+        "payload": {
+            "headers": [
+                {"name": "From", "value": "sender4@example.com"},
+                {"name": "Subject", "value": "Partial Headers"},
+                # 'To' and 'Date' headers are missing
+            ],
+            "body": {"size": 100, "data": "TWlzc2luZyBzb21lIGhlYWRlcnMu"},
+        },
+    }
+
+    with (
+        patch("arcade_google.tools.utils._get_email_plain_text_body") as mock_plain,
+        patch("arcade_google.tools.utils._get_email_html_body") as mock_html,
+        patch("arcade_google.tools.utils._clean_email_body") as mock_clean,
+    ):
+        # Mock the helper functions
+        mock_plain.return_value = "Missing some headers."
+        mock_html.return_value = None
+        mock_clean.return_value = "Missing some headers."
+
+        result = parse_multipart_email(email_data)
+
+    assert result["id"] == "email222"
+    assert result["thread_id"] == "thread222"
+    assert result["label_ids"] == ["INBOX"]
+    assert result["snippet"] == "Missing some headers."
+    assert result["to"] == ""
+    assert result["from"] == "sender4@example.com"
+    assert result["subject"] == "Partial Headers"
+    assert result["date"] == ""
+    assert result["plain_text_body"] == "Missing some headers."
+    assert result["html_body"] == ""
+
+
+def test_parse_multipart_email_empty():
+    """
+    Test parsing an empty email data.
+    """
+    email_data = {}
+
+    result = parse_multipart_email(email_data)
+
+    assert result["id"] == ""
+    assert result["thread_id"] == ""
+    assert result["label_ids"] == []
+    assert result["snippet"] == ""
+    assert result["to"] == ""
+    assert result["from"] == ""
+    assert result["subject"] == ""
+    assert result["date"] == ""
+    assert result["plain_text_body"] == ""
+    assert result["html_body"] == ""
+
+
+def test_parse_multipart_email_invalid_payload_structure():
+    """
+    Test parsing an email with an invalid payload structure.
+    """
+    email_data = {
+        "id": "email333",
+        "threadId": "thread333",
+        "labelIds": ["INBOX"],
+        "historyId": "history333",
+        "snippet": "Invalid payload structure.",
+        "payload": {
+            "headers": "This should be a list, not a string",
+            "body": {"size": 100, "data": "SW52YWxpZCBwYXlsb2Fk"},
+        },
+    }
+
+    with pytest.raises(TypeError):
+        parse_multipart_email(email_data)