diff --git a/app/controllers/api/v1/accounts/agent_bots_controller.rb b/app/controllers/api/v1/accounts/agent_bots_controller.rb
index 64c35d33d..c2f919659 100644
--- a/app/controllers/api/v1/accounts/agent_bots_controller.rb
+++ b/app/controllers/api/v1/accounts/agent_bots_controller.rb
@@ -4,7 +4,7 @@ class Api::V1::Accounts::AgentBotsController < Api::V1::Accounts::BaseController
   before_action :agent_bot, except: [:index, :create]
 
   def index
-    @agent_bots = AgentBot.where(account_id: [nil, Current.account.id])
+    @agent_bots = AgentBot.accessible_to(Current.account)
   end
 
   def show; end
@@ -37,7 +37,7 @@ class Api::V1::Accounts::AgentBotsController < Api::V1::Accounts::BaseController
   private
 
   def agent_bot
-    @agent_bot = AgentBot.where(account_id: [nil, Current.account.id]).find(params[:id]) if params[:action] == 'show'
+    @agent_bot = AgentBot.accessible_to(Current.account).find(params[:id]) if params[:action] == 'show'
     @agent_bot ||= Current.account.agent_bots.find(params[:id])
   end
 
diff --git a/app/controllers/api/v1/accounts/conversations/assignments_controller.rb b/app/controllers/api/v1/accounts/conversations/assignments_controller.rb
index 1fb2095e3..49806e97c 100644
--- a/app/controllers/api/v1/accounts/conversations/assignments_controller.rb
+++ b/app/controllers/api/v1/accounts/conversations/assignments_controller.rb
@@ -1,7 +1,7 @@
 class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Accounts::Conversations::BaseController
   # assigns agent/team to a conversation
   def create
-    if params.key?(:assignee_id)
+    if params.key?(:assignee_id) || agent_bot_assignment?
       set_agent
     elsif params.key?(:team_id)
       set_team
@@ -13,17 +13,23 @@ class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Account
   private
 
   def set_agent
-    @agent = Current.account.users.find_by(id: params[:assignee_id])
-    @conversation.assignee = @agent
-    @conversation.save!
-    render_agent
+    resource = Conversations::AssignmentService.new(
+      conversation: @conversation,
+      assignee_id: params[:assignee_id],
+      assignee_type: params[:assignee_type]
+    ).perform
+
+    render_agent(resource)
   end
 
-  def render_agent
-    if @agent.nil?
-      render json: nil
+  def render_agent(resource)
+    case resource
+    when User
+      render partial: 'api/v1/models/agent', formats: [:json], locals: { resource: resource }
+    when AgentBot
+      render partial: 'api/v1/models/agent_bot_slim', formats: [:json], locals: { resource: resource }
     else
-      render partial: 'api/v1/models/agent', formats: [:json], locals: { resource: @agent }
+      render json: nil
     end
   end
 
@@ -32,4 +38,8 @@ class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Account
     @conversation.update!(team: @team)
     render json: @team
   end
+
+  def agent_bot_assignment?
+    params[:assignee_type].to_s == 'AgentBot'
+  end
 end
diff --git a/app/controllers/concerns/ensure_current_account_helper.rb b/app/controllers/concerns/ensure_current_account_helper.rb
index 3baf9ee1e..ea36a48f2 100644
--- a/app/controllers/concerns/ensure_current_account_helper.rb
+++ b/app/controllers/concerns/ensure_current_account_helper.rb
@@ -25,6 +25,9 @@ module EnsureCurrentAccountHelper
   end
 
   def account_accessible_for_bot?(account)
-    render_unauthorized('Bot is not authorized to access this account') unless @resource.agent_bot_inboxes.find_by(account_id: account.id)
+    return if @resource.account_id == account.id
+    return if @resource.agent_bot_inboxes.find_by(account_id: account.id)
+
+    render_unauthorized('Bot is not authorized to access this account')
   end
 end
diff --git a/app/javascript/dashboard/api/inbox/conversation.js b/app/javascript/dashboard/api/inbox/conversation.js
index 0f539bfa9..f94fca452 100644
--- a/app/javascript/dashboard/api/inbox/conversation.js
+++ b/app/javascript/dashboard/api/inbox/conversation.js
@@ -63,10 +63,9 @@ class ConversationApi extends ApiClient {
   }
 
   assignAgent({ conversationId, agentId }) {
-    return axios.post(
-      `${this.url}/${conversationId}/assignments?assignee_id=${agentId}`,
-      {}
-    );
+    return axios.post(`${this.url}/${conversationId}/assignments`, {
+      assignee_id: agentId,
+    });
   }
 
   assignTeam({ conversationId, teamId }) {
diff --git a/app/javascript/dashboard/api/specs/inbox/conversation.spec.js b/app/javascript/dashboard/api/specs/inbox/conversation.spec.js
index dd1615802..de0d7a7d0 100644
--- a/app/javascript/dashboard/api/specs/inbox/conversation.spec.js
+++ b/app/javascript/dashboard/api/specs/inbox/conversation.spec.js
@@ -92,8 +92,10 @@ describe('#ConversationAPI', () => {
     it('#assignAgent', () => {
       conversationAPI.assignAgent({ conversationId: 12, agentId: 34 });
       expect(axiosMock.post).toHaveBeenCalledWith(
-        `/api/v1/conversations/12/assignments?assignee_id=34`,
-        {}
+        `/api/v1/conversations/12/assignments`,
+        {
+          assignee_id: 34,
+        }
       );
     });
 
diff --git a/app/javascript/dashboard/components/widgets/conversation/ReplyBoxBanner.vue b/app/javascript/dashboard/components/widgets/conversation/ReplyBoxBanner.vue
index 3aea41f90..d80910343 100644
--- a/app/javascript/dashboard/components/widgets/conversation/ReplyBoxBanner.vue
+++ b/app/javascript/dashboard/components/widgets/conversation/ReplyBoxBanner.vue
@@ -30,7 +30,7 @@ const assignedAgent = computed({
     return currentChat.value?.meta?.assignee;
   },
   set(agent) {
-    const agentId = agent ? agent.id : 0;
+    const agentId = agent ? agent.id : null;
     store.dispatch('setCurrentChatAssignee', agent);
     store.dispatch('assignAgent', {
       conversationId: currentChat.value?.id,
diff --git a/app/javascript/dashboard/routes/dashboard/conversation/ConversationAction.vue b/app/javascript/dashboard/routes/dashboard/conversation/ConversationAction.vue
index f94fc7a9b..76533a94d 100644
--- a/app/javascript/dashboard/routes/dashboard/conversation/ConversationAction.vue
+++ b/app/javascript/dashboard/routes/dashboard/conversation/ConversationAction.vue
@@ -84,7 +84,7 @@ export default {
         return this.currentChat.meta.assignee;
       },
       set(agent) {
-        const agentId = agent ? agent.id : 0;
+        const agentId = agent ? agent.id : null;
         this.$store.dispatch('setCurrentChatAssignee', agent);
         this.$store
           .dispatch('assignAgent', {
diff --git a/app/listeners/agent_bot_listener.rb b/app/listeners/agent_bot_listener.rb
index 38c046e34..ccac8005f 100644
--- a/app/listeners/agent_bot_listener.rb
+++ b/app/listeners/agent_bot_listener.rb
@@ -2,61 +2,60 @@ class AgentBotListener < BaseListener
   def conversation_resolved(event)
     conversation = extract_conversation_and_account(event)[0]
     inbox = conversation.inbox
-    return unless connected_agent_bot_exist?(inbox)
-
     event_name = __method__.to_s
     payload = conversation.webhook_data.merge(event: event_name)
-    process_webhook_bot_event(inbox.agent_bot, payload)
+    agent_bots_for(inbox, conversation).each { |agent_bot| process_webhook_bot_event(agent_bot, payload) }
   end
 
   def conversation_opened(event)
     conversation = extract_conversation_and_account(event)[0]
     inbox = conversation.inbox
-    return unless connected_agent_bot_exist?(inbox)
-
     event_name = __method__.to_s
     payload = conversation.webhook_data.merge(event: event_name)
-    process_webhook_bot_event(inbox.agent_bot, payload)
+    agent_bots_for(inbox, conversation).each { |agent_bot| process_webhook_bot_event(agent_bot, payload) }
   end
 
   def message_created(event)
     message = extract_message_and_account(event)[0]
     inbox = message.inbox
-    return unless connected_agent_bot_exist?(inbox)
     return unless message.webhook_sendable?
 
     method_name = __method__.to_s
-    process_message_event(method_name, inbox.agent_bot, message, event)
+    agent_bots_for(inbox, message.conversation).each { |agent_bot| process_message_event(method_name, agent_bot, message, event) }
   end
 
   def message_updated(event)
     message = extract_message_and_account(event)[0]
     inbox = message.inbox
-    return unless connected_agent_bot_exist?(inbox)
     return unless message.webhook_sendable?
 
     method_name = __method__.to_s
-    process_message_event(method_name, inbox.agent_bot, message, event)
+    agent_bots_for(inbox, message.conversation).each { |agent_bot| process_message_event(method_name, agent_bot, message, event) }
   end
 
   def webwidget_triggered(event)
     contact_inbox = event.data[:contact_inbox]
     inbox = contact_inbox.inbox
-    return unless connected_agent_bot_exist?(inbox)
-
     event_name = __method__.to_s
     payload = contact_inbox.webhook_data.merge(event: event_name)
     payload[:event_info] = event.data[:event_info]
-    process_webhook_bot_event(inbox.agent_bot, payload)
+    agent_bots_for(inbox).each { |agent_bot| process_webhook_bot_event(agent_bot, payload) }
   end
 
   private
 
-  def connected_agent_bot_exist?(inbox)
-    return if inbox.agent_bot_inbox.blank?
-    return unless inbox.agent_bot_inbox.active?
+  def agent_bots_for(inbox, conversation = nil)
+    bots = []
+    bots << conversation.assignee_agent_bot if conversation&.assignee_agent_bot.present?
+    inbox_bot = active_inbox_agent_bot(inbox)
+    bots << inbox_bot if inbox_bot.present?
+    bots.compact.uniq
+  end
 
-    true
+  def active_inbox_agent_bot(inbox)
+    return unless inbox.agent_bot_inbox&.active?
+
+    inbox.agent_bot
   end
 
   def process_message_event(method_name, agent_bot, message, _event)
diff --git a/app/models/agent_bot.rb b/app/models/agent_bot.rb
index be63aebc5..b839f21b4 100644
--- a/app/models/agent_bot.rb
+++ b/app/models/agent_bot.rb
@@ -21,9 +21,18 @@ class AgentBot < ApplicationRecord
   include AccessTokenable
   include Avatarable
 
+  scope :accessible_to, lambda { |account|
+    account_id = account&.id
+    where(account_id: [nil, account_id])
+  }
+
   has_many :agent_bot_inboxes, dependent: :destroy_async
   has_many :inboxes, through: :agent_bot_inboxes
   has_many :messages, as: :sender, dependent: :nullify
+  has_many :assigned_conversations, class_name: 'Conversation',
+                                    foreign_key: :assignee_agent_bot_id,
+                                    dependent: :nullify,
+                                    inverse_of: :assignee_agent_bot
   belongs_to :account, optional: true
   enum bot_type: { webhook: 0 }
 
diff --git a/app/models/conversation.rb b/app/models/conversation.rb
index ca8a3258e..ac0985416 100644
--- a/app/models/conversation.rb
+++ b/app/models/conversation.rb
@@ -20,6 +20,7 @@
 #  created_at             :datetime         not null
 #  updated_at             :datetime         not null
 #  account_id             :integer          not null
+#  assignee_agent_bot_id  :bigint
 #  assignee_id            :integer
 #  campaign_id            :bigint
 #  contact_id             :bigint
@@ -65,6 +66,7 @@ class Conversation < ApplicationRecord
   validates :inbox_id, presence: true
   validates :contact_id, presence: true
   before_validation :validate_additional_attributes
+  before_validation :reset_agent_bot_when_assignee_present
   validates :additional_attributes, jsonb_attributes_length: true
   validates :custom_attributes, jsonb_attributes_length: true
   validates :uuid, uniqueness: true
@@ -98,6 +100,7 @@ class Conversation < ApplicationRecord
   belongs_to :account
   belongs_to :inbox
   belongs_to :assignee, class_name: 'User', optional: true, inverse_of: :assigned_conversations
+  belongs_to :assignee_agent_bot, class_name: 'AgentBot', optional: true
   belongs_to :contact
   belongs_to :contact_inbox
   belongs_to :team, optional: true
@@ -180,6 +183,18 @@ class Conversation < ApplicationRecord
     true
   end
 
+  # Virtual attribute till we switch completely to polymorphic assignee
+  def assignee_type
+    return 'AgentBot' if assignee_agent_bot_id.present?
+    return 'User' if assignee_id.present?
+
+    nil
+  end
+
+  def assigned_entity
+    assignee_agent_bot || assignee
+  end
+
   def tweet?
     inbox.inbox_type == 'Twitter' && additional_attributes['type'] == 'tweet'
   end
@@ -226,6 +241,12 @@ class Conversation < ApplicationRecord
     self.additional_attributes = {} unless additional_attributes.is_a?(Hash)
   end
 
+  def reset_agent_bot_when_assignee_present
+    return if assignee_id.blank?
+
+    self.assignee_agent_bot_id = nil
+  end
+
   def determine_conversation_status
     self.status = :resolved and return if contact.blocked?
 
@@ -251,8 +272,8 @@ class Conversation < ApplicationRecord
   end
 
   def list_of_keys
-    %w[team_id assignee_id status snoozed_until custom_attributes label_list waiting_since first_reply_created_at
-       priority]
+    %w[team_id assignee_id assignee_agent_bot_id status snoozed_until custom_attributes label_list waiting_since
+       first_reply_created_at priority]
   end
 
   def allowed_keys?
diff --git a/app/presenters/conversations/event_data_presenter.rb b/app/presenters/conversations/event_data_presenter.rb
index 2ef69080d..4a9216b05 100644
--- a/app/presenters/conversations/event_data_presenter.rb
+++ b/app/presenters/conversations/event_data_presenter.rb
@@ -30,7 +30,8 @@ class Conversations::EventDataPresenter < SimpleDelegator
   def push_meta
     {
       sender: contact.push_event_data,
-      assignee: assignee&.push_event_data,
+      assignee: assigned_entity&.push_event_data,
+      assignee_type: assignee_type,
       team: team&.push_event_data,
       hmac_verified: contact_inbox&.hmac_verified
     }
diff --git a/app/services/conversations/assignment_service.rb b/app/services/conversations/assignment_service.rb
new file mode 100644
index 000000000..adca34f06
--- /dev/null
+++ b/app/services/conversations/assignment_service.rb
@@ -0,0 +1,43 @@
+class Conversations::AssignmentService
+  def initialize(conversation:, assignee_id:, assignee_type: nil)
+    @conversation = conversation
+    @assignee_id = assignee_id
+    @assignee_type = assignee_type
+  end
+
+  def perform
+    agent_bot_assignment? ? assign_agent_bot : assign_agent
+  end
+
+  private
+
+  attr_reader :conversation, :assignee_id, :assignee_type
+
+  def assign_agent
+    conversation.assignee = assignee
+    conversation.assignee_agent_bot = nil
+    conversation.save!
+    assignee
+  end
+
+  def assign_agent_bot
+    return unless agent_bot
+
+    conversation.assignee = nil
+    conversation.assignee_agent_bot = agent_bot
+    conversation.save!
+    agent_bot
+  end
+
+  def assignee
+    @assignee ||= conversation.account.users.find_by(id: assignee_id)
+  end
+
+  def agent_bot
+    @agent_bot ||= AgentBot.accessible_to(conversation.account).find_by(id: assignee_id)
+  end
+
+  def agent_bot_assignment?
+    assignee_type.to_s == 'AgentBot'
+  end
+end
diff --git a/app/views/api/v1/accounts/conversations/assignments/create.json.jbuilder b/app/views/api/v1/accounts/conversations/assignments/create.json.jbuilder
deleted file mode 100644
index 1c5bd4846..000000000
--- a/app/views/api/v1/accounts/conversations/assignments/create.json.jbuilder
+++ /dev/null
@@ -1,4 +0,0 @@
-json.payload do
-  json.assignee @conversation.assignee
-  json.conversation_id @conversation.display_id
-end
diff --git a/app/views/api/v1/conversations/partials/_conversation.json.jbuilder b/app/views/api/v1/conversations/partials/_conversation.json.jbuilder
index 8867ba695..4cb13f543 100644
--- a/app/views/api/v1/conversations/partials/_conversation.json.jbuilder
+++ b/app/views/api/v1/conversations/partials/_conversation.json.jbuilder
@@ -7,10 +7,16 @@ json.meta do
     json.partial! 'api/v1/models/contact', formats: [:json], resource: conversation.contact
   end
   json.channel conversation.inbox.try(:channel_type)
-  if conversation.assignee&.account
+  if conversation.assigned_entity.is_a?(AgentBot)
     json.assignee do
-      json.partial! 'api/v1/models/agent', formats: [:json], resource: conversation.assignee
+      json.partial! 'api/v1/models/agent_bot_slim', formats: [:json], resource: conversation.assigned_entity
     end
+    json.assignee_type 'AgentBot'
+  elsif conversation.assigned_entity&.account
+    json.assignee do
+      json.partial! 'api/v1/models/agent', formats: [:json], resource: conversation.assigned_entity
+    end
+    json.assignee_type 'User'
   end
   if conversation.team.present?
     json.team do
diff --git a/app/views/api/v1/models/_agent_bot_slim.json.jbuilder b/app/views/api/v1/models/_agent_bot_slim.json.jbuilder
new file mode 100644
index 000000000..29f1e12a5
--- /dev/null
+++ b/app/views/api/v1/models/_agent_bot_slim.json.jbuilder
@@ -0,0 +1,6 @@
+json.id resource.id
+json.name resource.name
+json.description resource.description
+json.thumbnail resource.avatar_url
+json.outgoing_url resource.outgoing_url unless resource.system_bot?
+json.bot_type resource.bot_type
diff --git a/db/migrate/20251022162159_add_assignee_agent_bot_id_to_conversations.rb b/db/migrate/20251022162159_add_assignee_agent_bot_id_to_conversations.rb
new file mode 100644
index 000000000..0a96c319e
--- /dev/null
+++ b/db/migrate/20251022162159_add_assignee_agent_bot_id_to_conversations.rb
@@ -0,0 +1,5 @@
+class AddAssigneeAgentBotIdToConversations < ActiveRecord::Migration[7.1]
+  def change
+    add_column :conversations, :assignee_agent_bot_id, :bigint
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 8a6e6676c..b69b5f61b 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -668,6 +668,7 @@ ActiveRecord::Schema[7.1].define(version: 2025_11_14_173609) do
     t.bigint "sla_policy_id"
     t.datetime "waiting_since"
     t.text "cached_label_list"
+    t.bigint "assignee_agent_bot_id"
     t.index ["account_id", "display_id"], name: "index_conversations_on_account_id_and_display_id", unique: true
     t.index ["account_id", "id"], name: "index_conversations_on_id_and_account_id"
     t.index ["account_id", "inbox_id", "status", "assignee_id"], name: "conv_acid_inbid_stat_asgnid_idx"
diff --git a/spec/controllers/api/v1/accounts/conversations/assignments_controller_spec.rb b/spec/controllers/api/v1/accounts/conversations/assignments_controller_spec.rb
index 8ed70b7a2..18c652c0a 100644
--- a/spec/controllers/api/v1/accounts/conversations/assignments_controller_spec.rb
+++ b/spec/controllers/api/v1/accounts/conversations/assignments_controller_spec.rb
@@ -15,7 +15,7 @@ RSpec.describe 'Conversation Assignment API', type: :request do
     end
 
     context 'when it is an authenticated bot with out access to the inbox' do
-      let(:agent_bot) { create(:agent_bot, account: account) }
+      let(:agent_bot) { create(:agent_bot) }
       let(:agent) { create(:user, account: account, role: :agent) }
 
       before do
@@ -36,6 +36,7 @@ RSpec.describe 'Conversation Assignment API', type: :request do
 
     context 'when it is an authenticated user with access to the inbox' do
       let(:agent) { create(:user, account: account, role: :agent) }
+      let(:agent_bot) { create(:agent_bot, account: account) }
       let(:team) { create(:team, account: account) }
 
       before do
@@ -54,6 +55,25 @@ RSpec.describe 'Conversation Assignment API', type: :request do
         expect(conversation.reload.assignee).to eq(agent)
       end
 
+      it 'assigns an agent bot to the conversation' do
+        params = { assignee_id: agent_bot.id, assignee_type: 'AgentBot' }
+
+        expect(Conversations::AssignmentService).to receive(:new)
+          .with(hash_including(conversation: conversation, assignee_id: agent_bot.id, assignee_type: 'AgentBot'))
+          .and_call_original
+
+        post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
+             params: params,
+             headers: agent.create_new_auth_token,
+             as: :json
+
+        expect(response).to have_http_status(:success)
+        expect(response.parsed_body['name']).to eq(agent_bot.name)
+        conversation.reload
+        expect(conversation.assignee_agent_bot).to eq(agent_bot)
+        expect(conversation.assignee).to be_nil
+      end
+
       it 'assigns a team to the conversation' do
         team_member = create(:user, account: account, role: :agent, auto_offline: false)
         create(:inbox_member, inbox: conversation.inbox, user: team_member)
@@ -125,7 +145,7 @@ RSpec.describe 'Conversation Assignment API', type: :request do
       end
 
       it 'unassigns the assignee from the conversation' do
-        params = { assignee_id: 0 }
+        params = { assignee_id: nil }
         post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
              params: params,
              headers: agent.create_new_auth_token,
diff --git a/spec/listeners/agent_bot_listener_spec.rb b/spec/listeners/agent_bot_listener_spec.rb
index 2dc2b41df..56c478a1b 100644
--- a/spec/listeners/agent_bot_listener_spec.rb
+++ b/spec/listeners/agent_bot_listener_spec.rb
@@ -36,6 +36,24 @@ describe AgentBotListener do
         expect(AgentBots::WebhookJob).not_to receive(:perform_later)
         listener.message_created(event)
       end
+
+      context 'when conversation has a different assignee agent bot' do
+        let!(:conversation_bot) { create(:agent_bot) }
+
+        before do
+          create(:agent_bot_inbox, inbox: inbox, agent_bot: agent_bot)
+          conversation.update!(assignee_agent_bot: conversation_bot, assignee: nil)
+        end
+
+        it 'sends message to both bots exactly once' do
+          payload = message.webhook_data.merge(event: 'message_created')
+
+          expect(AgentBots::WebhookJob).to receive(:perform_later).with(agent_bot.outgoing_url, payload).once
+          expect(AgentBots::WebhookJob).to receive(:perform_later).with(conversation_bot.outgoing_url, payload).once
+
+          listener.message_created(event)
+        end
+      end
     end
   end
 
diff --git a/spec/models/conversation_spec.rb b/spec/models/conversation_spec.rb
index 51bb43384..7a5398456 100644
--- a/spec/models/conversation_spec.rb
+++ b/spec/models/conversation_spec.rb
@@ -525,8 +525,9 @@ RSpec.describe Conversation do
         additional_attributes: {},
         meta: {
           sender: conversation.contact.push_event_data,
-          assignee: conversation.assignee,
-          team: conversation.team,
+          assignee: conversation.assigned_entity&.push_event_data,
+          assignee_type: conversation.assignee_type,
+          team: conversation.team&.push_event_data,
           hmac_verified: conversation.contact_inbox.hmac_verified
         },
         id: conversation.display_id,
diff --git a/spec/presenters/conversations/event_data_presenter_spec.rb b/spec/presenters/conversations/event_data_presenter_spec.rb
index a645caf1d..bf0eaf6f6 100644
--- a/spec/presenters/conversations/event_data_presenter_spec.rb
+++ b/spec/presenters/conversations/event_data_presenter_spec.rb
@@ -12,8 +12,9 @@ RSpec.describe Conversations::EventDataPresenter do
         additional_attributes: {},
         meta: {
           sender: conversation.contact.push_event_data,
-          assignee: conversation.assignee,
-          team: conversation.team,
+          assignee: conversation.assigned_entity&.push_event_data,
+          assignee_type: conversation.assignee_type,
+          team: conversation.team&.push_event_data,
           hmac_verified: conversation.contact_inbox.hmac_verified
         },
         id: conversation.display_id,
diff --git a/spec/requests/api/v1/accounts/base_controller_spec.rb b/spec/requests/api/v1/accounts/base_controller_spec.rb
new file mode 100644
index 000000000..6493bc986
--- /dev/null
+++ b/spec/requests/api/v1/accounts/base_controller_spec.rb
@@ -0,0 +1,63 @@
+require 'rails_helper'
+
+RSpec.describe 'Api::V1::Accounts::BaseController', type: :request do
+  let(:account) { create(:account) }
+  let(:inbox) { create(:inbox, account: account) }
+  let!(:conversation) { create(:conversation, account: account, inbox: inbox) }
+  let(:agent) { create(:user, account: account, role: :agent) }
+
+  before do
+    create(:inbox_member, inbox: inbox, user: agent)
+  end
+
+  context 'when agent bot belongs to the account' do
+    let(:agent_bot) { create(:agent_bot, account: account) }
+
+    it 'allows assignments via API' do
+      post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
+           headers: { api_access_token: agent_bot.access_token.token },
+           params: { assignee_id: agent.id },
+           as: :json
+
+      expect(response).to have_http_status(:success)
+    end
+  end
+
+  context 'when agent bot belongs to another account' do
+    let(:other_account) { create(:account) }
+    let(:external_bot) { create(:agent_bot, account: other_account) }
+
+    it 'rejects assignment' do
+      post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
+           headers: { api_access_token: external_bot.access_token.token },
+           params: { assignee_id: agent.id },
+           as: :json
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+  end
+
+  context 'when agent bot is global' do
+    let(:global_bot) { create(:agent_bot, account: nil) }
+
+    it 'rejects requests without inbox mapping' do
+      post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
+           headers: { api_access_token: global_bot.access_token.token },
+           params: { assignee_id: agent.id },
+           as: :json
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'allows requests when inbox mapping exists' do
+      create(:agent_bot_inbox, agent_bot: global_bot, inbox: inbox)
+
+      post api_v1_account_conversation_assignments_url(account_id: account.id, conversation_id: conversation.display_id),
+           headers: { api_access_token: global_bot.access_token.token },
+           params: { assignee_id: agent.id },
+           as: :json
+
+      expect(response).to have_http_status(:success)
+    end
+  end
+end
diff --git a/spec/services/conversations/assignment_service_spec.rb b/spec/services/conversations/assignment_service_spec.rb
new file mode 100644
index 000000000..899236e1d
--- /dev/null
+++ b/spec/services/conversations/assignment_service_spec.rb
@@ -0,0 +1,60 @@
+require 'rails_helper'
+
+describe Conversations::AssignmentService do
+  let(:account) { create(:account) }
+  let(:agent) { create(:user, account: account) }
+  let(:agent_bot) { create(:agent_bot, account: account) }
+  let(:conversation) { create(:conversation, account: account) }
+
+  describe '#perform' do
+    context 'when assignee_id is blank' do
+      before do
+        conversation.update!(assignee: agent, assignee_agent_bot: agent_bot)
+      end
+
+      it 'clears both human and bot assignees' do
+        described_class.new(conversation: conversation, assignee_id: nil).perform
+
+        conversation.reload
+        expect(conversation.assignee_id).to be_nil
+        expect(conversation.assignee_agent_bot_id).to be_nil
+      end
+    end
+
+    context 'when assigning a user' do
+      before do
+        conversation.update!(assignee_agent_bot: agent_bot, assignee: nil)
+      end
+
+      it 'sets the agent and clears agent bot' do
+        result = described_class.new(conversation: conversation, assignee_id: agent.id).perform
+
+        conversation.reload
+        expect(result).to eq(agent)
+        expect(conversation.assignee_id).to eq(agent.id)
+        expect(conversation.assignee_agent_bot_id).to be_nil
+      end
+    end
+
+    context 'when assigning an agent bot' do
+      let(:service) do
+        described_class.new(
+          conversation: conversation,
+          assignee_id: agent_bot.id,
+          assignee_type: 'AgentBot'
+        )
+      end
+
+      it 'sets the agent bot and clears human assignee' do
+        conversation.update!(assignee: agent, assignee_agent_bot: nil)
+
+        result = service.perform
+
+        conversation.reload
+        expect(result).to eq(agent_bot)
+        expect(conversation.assignee_agent_bot_id).to eq(agent_bot.id)
+        expect(conversation.assignee_id).to be_nil
+      end
+    end
+  end
+end