diff --git a/monkey/infection_monkey/master/control_channel.py b/monkey/infection_monkey/master/control_channel.py
index 713ac3aac..28b6d7533 100644
--- a/monkey/infection_monkey/master/control_channel.py
+++ b/monkey/infection_monkey/master/control_channel.py
@@ -32,7 +32,8 @@ class ControlChannel(IControlChannel):
             id=get_agent_id(),
             machine_hardware_id=get_machine_id(),
             start_time=agent_process.get_start_time(),
-            parent_id=parent,
+            # parent_id=parent,
+            parent_id=None,  # None for now, until we change GUID to UUID
             cc_server=self._control_channel_server,
             network_interfaces=get_network_interfaces(),
         )
diff --git a/monkey/monkey_island/cc/models/__init__.py b/monkey/monkey_island/cc/models/__init__.py
index 94e063a81..521e7f720 100644
--- a/monkey/monkey_island/cc/models/__init__.py
+++ b/monkey/monkey_island/cc/models/__init__.py
@@ -12,4 +12,4 @@ from .user_credentials import UserCredentials
 from .machine import Machine, MachineID
 from .communication_type import CommunicationType
 from .node import Node
-from .agent import Agent
+from .agent import Agent, AgentID
diff --git a/monkey/monkey_island/cc/models/agent.py b/monkey/monkey_island/cc/models/agent.py
index 1740e264d..66bca7b54 100644
--- a/monkey/monkey_island/cc/models/agent.py
+++ b/monkey/monkey_island/cc/models/agent.py
@@ -3,17 +3,35 @@ from typing import Optional
 from uuid import UUID
 
 from pydantic import Field
+from typing_extensions import TypeAlias
 
 from common.base_models import MutableInfectionMonkeyBaseModel
 
 from . import MachineID
 
+AgentID: TypeAlias = UUID
+
 
 class Agent(MutableInfectionMonkeyBaseModel):
-    id: UUID = Field(..., allow_mutation=False)
+    """Represents an agent that has run on a victim machine"""
+
+    id: AgentID = Field(..., allow_mutation=False)
+    """Uniquely identifies an instance of an agent"""
+
     machine_id: MachineID = Field(..., allow_mutation=False)
+    """The machine that the agent ran on"""
+
     start_time: datetime = Field(..., allow_mutation=False)
+    """The time the agent process started"""
+
     stop_time: Optional[datetime]
-    parent_id: UUID = Field(..., allow_mutation=False)
+    """The time the agent process exited"""
+
+    parent_id: Optional[AgentID] = Field(allow_mutation=False)
+    """The ID of the parent agent that spawned this agent"""
+
     cc_server: str = Field(default="")
+    """The address that the agent used to communicate with the island"""
+
     log_contents: str = Field(default="")
+    """The contents of the agent's log (empty until the agent shuts down)"""
diff --git a/monkey/monkey_island/cc/repository/__init__.py b/monkey/monkey_island/cc/repository/__init__.py
index caef77b9b..e1d5fd47b 100644
--- a/monkey/monkey_island/cc/repository/__init__.py
+++ b/monkey/monkey_island/cc/repository/__init__.py
@@ -8,6 +8,7 @@ from .i_simulation_repository import ISimulationRepository
 from .i_credentials_repository import ICredentialsRepository
 from .i_user_repository import IUserRepository
 from .i_machine_repository import IMachineRepository
+from .i_agent_repository import IAgentRepository
 
 
 from .local_storage_file_repository import LocalStorageFileRepository
@@ -21,3 +22,4 @@ from .file_simulation_repository import FileSimulationRepository
 from .json_file_user_repository import JSONFileUserRepository
 from .mongo_credentials_repository import MongoCredentialsRepository
 from .mongo_machine_repository import MongoMachineRepository
+from .mongo_agent_repository import MongoAgentRepository
diff --git a/monkey/monkey_island/cc/repository/i_agent_repository.py b/monkey/monkey_island/cc/repository/i_agent_repository.py
index 5a784e5d2..880b4d7e7 100644
--- a/monkey/monkey_island/cc/repository/i_agent_repository.py
+++ b/monkey/monkey_island/cc/repository/i_agent_repository.py
@@ -1,15 +1,47 @@
-from abc import ABC
-from typing import Optional, Sequence
+from abc import ABC, abstractmethod
+from typing import Sequence
 
-from monkey_island.cc.models import Monkey
+from monkey_island.cc.models import Agent, AgentID
 
 
 class IAgentRepository(ABC):
-    # TODO rename Monkey document to Agent
-    def save_agent(self, agent: Monkey):
-        pass
+    """A repository used to store and retrieve `Agent` objects"""
 
-    def get_agents(
-        self, id: Optional[str] = None, running: Optional[bool] = None
-    ) -> Sequence[Monkey]:
-        pass
+    @abstractmethod
+    def upsert_agent(self, agent: Agent):
+        """
+        Upsert (insert or update) an `Agent`
+
+        Insert the `Agent` if no `Agent` with a matching ID exists in the repository. If the agent
+        already exists, update it.
+
+        :param agent: The `agent` to be inserted or updated
+        :raises StorageError: If an error occurred while attempting to store the `Agent`
+        """
+
+    @abstractmethod
+    def get_agent_by_id(self, agent_id: AgentID) -> Agent:
+        """
+        Get an `Agent` by ID
+
+        :param agent_id: The ID of the `Agent` to be retrieved
+        :return: An `Agent` with a matching `id`
+        :raises UnknownRecordError: If an `Agent` with the specified `id` does not exist in the
+                                    repository
+        :raises RetrievalError: If an error occurred while attempting to retrieve the `Agent`
+        """
+
+    @abstractmethod
+    def get_running_agents(self) -> Sequence[Agent]:
+        """
+        Get all `Agents` that are currently running
+
+        :return: All `Agents` that are currently running
+        :raises RetrievalError: If an error occurred while attempting to retrieve the `Agents`
+        """
+
+    @abstractmethod
+    def reset(self):
+        """
+        Removes all data from the repository
+        """
diff --git a/monkey/monkey_island/cc/repository/mongo_agent_repository.py b/monkey/monkey_island/cc/repository/mongo_agent_repository.py
new file mode 100644
index 000000000..3b1b60f0a
--- /dev/null
+++ b/monkey/monkey_island/cc/repository/mongo_agent_repository.py
@@ -0,0 +1,68 @@
+from typing import Any, MutableMapping, Sequence
+
+from pymongo import MongoClient
+
+from monkey_island.cc.models import Agent, AgentID
+from monkey_island.cc.repository import (
+    IAgentRepository,
+    RemovalError,
+    RetrievalError,
+    StorageError,
+    UnknownRecordError,
+)
+
+from .consts import MONGO_OBJECT_ID_KEY
+
+
+class MongoAgentRepository(IAgentRepository):
+    def __init__(self, mongo_client: MongoClient):
+        self._agents_collection = mongo_client.monkey_island.agents
+
+    def upsert_agent(self, agent: Agent):
+        try:
+            result = self._agents_collection.replace_one(
+                {"id": str(agent.id)}, agent.dict(simplify=True), upsert=True
+            )
+        except Exception as err:
+            raise StorageError(f'Error updating agent with ID "{agent.id}": {err}')
+
+        if result.matched_count != 0 and result.modified_count != 1:
+            raise StorageError(
+                f'Error updating agent with ID "{agent.id}": Expected to update 1 agent, '
+                f"but {result.modified_count} were updated"
+            )
+
+        if result.matched_count == 0 and result.upserted_id is None:
+            raise StorageError(
+                f'Error inserting agent with ID "{agent.id}": Expected to insert 1 agent, '
+                f"but no agents were inserted"
+            )
+
+    def get_agent_by_id(self, agent_id: AgentID) -> Agent:
+        try:
+            agent_dict = self._agents_collection.find_one({"id": str(agent_id)})
+        except Exception as err:
+            raise RetrievalError(f'Error retrieving agent with "id == {agent_id}": {err}')
+
+        if agent_dict is None:
+            raise UnknownRecordError(f'Unknown ID "{agent_id}"')
+
+        return MongoAgentRepository._mongo_record_to_agent(agent_dict)
+
+    def get_running_agents(self) -> Sequence[Agent]:
+        try:
+            cursor = self._agents_collection.find({"stop_time": None})
+            return list(map(MongoAgentRepository._mongo_record_to_agent, cursor))
+        except Exception as err:
+            raise RetrievalError(f"Error retrieving running agents: {err}")
+
+    @staticmethod
+    def _mongo_record_to_agent(mongo_record: MutableMapping[str, Any]) -> Agent:
+        del mongo_record[MONGO_OBJECT_ID_KEY]
+        return Agent(**mongo_record)
+
+    def reset(self):
+        try:
+            self._agents_collection.drop()
+        except Exception as err:
+            raise RemovalError(f"Error resetting the repository: {err}")
diff --git a/monkey/tests/unit_tests/monkey_island/cc/models/test_agent.py b/monkey/tests/unit_tests/monkey_island/cc/models/test_agent.py
index 1851a4873..fb528fd51 100644
--- a/monkey/tests/unit_tests/monkey_island/cc/models/test_agent.py
+++ b/monkey/tests/unit_tests/monkey_island/cc/models/test_agent.py
@@ -31,8 +31,11 @@ def test_constructor__defaults_from_objects():
 
 
 def test_constructor__defaults_from_simple_dict():
-    a = Agent(**AGENT_SIMPLE_DICT)
+    agent_simple_dict = AGENT_SIMPLE_DICT.copy()
+    del agent_simple_dict["parent_id"]
+    a = Agent(**agent_simple_dict)
 
+    assert a.parent_id is None
     assert a.stop_time is None
     assert a.cc_server == ""
     assert a.log_contents == ""
diff --git a/monkey/tests/unit_tests/monkey_island/cc/repository/test_mongo_agent_repository.py b/monkey/tests/unit_tests/monkey_island/cc/repository/test_mongo_agent_repository.py
new file mode 100644
index 000000000..4d3fa0d14
--- /dev/null
+++ b/monkey/tests/unit_tests/monkey_island/cc/repository/test_mongo_agent_repository.py
@@ -0,0 +1,168 @@
+from copy import deepcopy
+from datetime import datetime
+from unittest.mock import MagicMock
+from uuid import uuid4
+
+import mongomock
+import pytest
+
+from monkey_island.cc.models import Agent
+from monkey_island.cc.repository import (
+    IAgentRepository,
+    MongoAgentRepository,
+    RemovalError,
+    RetrievalError,
+    StorageError,
+    UnknownRecordError,
+)
+
+VICTIM_ZERO_ID = uuid4()
+RUNNING_AGENTS = (
+    Agent(id=VICTIM_ZERO_ID, machine_id=1, start_time=datetime.fromtimestamp(1661856718)),
+    Agent(
+        id=uuid4(),
+        machine_id=2,
+        start_time=datetime.fromtimestamp(1661856818),
+        parent_id=VICTIM_ZERO_ID,
+    ),
+)
+STOPPED_AGENTS = (
+    Agent(
+        id=uuid4(),
+        machine_id=3,
+        start_time=datetime.fromtimestamp(1661856758),
+        parent_id=VICTIM_ZERO_ID,
+        stop_time=datetime.fromtimestamp(1661856773),
+    ),
+)
+AGENTS = (
+    *RUNNING_AGENTS,
+    *STOPPED_AGENTS,
+)
+
+
+@pytest.fixture
+def agent_repository() -> IAgentRepository:
+    mongo_client = mongomock.MongoClient()
+    mongo_client.monkey_island.agents.insert_many((a.dict(simplify=True) for a in AGENTS))
+    return MongoAgentRepository(mongo_client)
+
+
+@pytest.fixture
+def empty_agent_repository() -> IAgentRepository:
+    mongo_client = mongomock.MongoClient()
+    return MongoAgentRepository(mongo_client)
+
+
+@pytest.fixture
+def error_raising_mock_mongo_client() -> mongomock.MongoClient:
+    mongo_client = MagicMock(spec=mongomock.MongoClient)
+    mongo_client.monkey_island = MagicMock(spec=mongomock.Database)
+    mongo_client.monkey_island.agents = MagicMock(spec=mongomock.Collection)
+
+    mongo_client.monkey_island.agents.drop = MagicMock(side_effect=Exception("some exception"))
+    mongo_client.monkey_island.agents.find = MagicMock(side_effect=Exception("some exception"))
+    mongo_client.monkey_island.agents.find_one = MagicMock(side_effect=Exception("some exception"))
+    mongo_client.monkey_island.agents.replace_one = MagicMock(
+        side_effect=Exception("some exception")
+    )
+
+    return mongo_client
+
+
+@pytest.fixture
+def error_raising_agent_repository(error_raising_mock_mongo_client) -> IAgentRepository:
+    return MongoAgentRepository(error_raising_mock_mongo_client)
+
+
+def test_upsert_agent__insert(agent_repository):
+    new_id = uuid4()
+    new_agent = Agent(
+        id=new_id,
+        machine_id=2,
+        start_time=datetime.fromtimestamp(1661858139),
+        parent_id=VICTIM_ZERO_ID,
+    )
+
+    agent_repository.upsert_agent(new_agent)
+
+    assert agent_repository.get_agent_by_id(new_id) == new_agent
+
+    for agent in AGENTS:
+        assert agent_repository.get_agent_by_id(agent.id) == agent
+
+
+def test_upsert_agent__insert_empty_repository(empty_agent_repository):
+    empty_agent_repository.upsert_agent(AGENTS[0])
+
+    assert empty_agent_repository.get_agent_by_id(VICTIM_ZERO_ID) == AGENTS[0]
+
+
+def test_upsert_agent__update(agent_repository):
+    agents = deepcopy(AGENTS)
+    agents[0].stop_time = datetime.now()
+    agents[0].cc_server = "127.0.0.1:1984"
+
+    agent_repository.upsert_agent(agents[0])
+
+    for agent in agents:
+        assert agent_repository.get_agent_by_id(agent.id) == agent
+
+
+def test_upsert_agent__storage_error(error_raising_agent_repository):
+    with pytest.raises(StorageError):
+        error_raising_agent_repository.upsert_agent(AGENTS[0])
+
+
+def test_get_agent_by_id(agent_repository):
+    for i, expected_agent in enumerate(AGENTS):
+        assert agent_repository.get_agent_by_id(expected_agent.id) == expected_agent
+
+
+def test_get_agent_by_id__not_found(agent_repository):
+    with pytest.raises(UnknownRecordError):
+        agent_repository.get_agent_by_id(uuid4())
+
+
+def test_get_agent_by_id__retrieval_error(error_raising_agent_repository):
+    with pytest.raises(RetrievalError):
+        error_raising_agent_repository.get_agent_by_id(AGENTS[0].id)
+
+
+def test_get_running_agents(agent_repository):
+    running_agents = agent_repository.get_running_agents()
+
+    assert len(running_agents) == len(RUNNING_AGENTS)
+    for a in running_agents:
+        assert a in RUNNING_AGENTS
+
+
+def test_get_running_agents__retrieval_error(error_raising_agent_repository):
+    with pytest.raises(RetrievalError):
+        error_raising_agent_repository.get_running_agents()
+
+
+def test_reset(agent_repository):
+    # Ensure the repository is not empty
+    for agent in AGENTS:
+        preexisting_agent = agent_repository.get_agent_by_id(agent.id)
+        assert isinstance(preexisting_agent, Agent)
+
+    agent_repository.reset()
+
+    for agent in AGENTS:
+        with pytest.raises(UnknownRecordError):
+            agent_repository.get_agent_by_id(agent.id)
+
+
+def test_usable_after_reset(agent_repository):
+    agent_repository.reset()
+
+    agent_repository.upsert_agent(AGENTS[0])
+
+    assert agent_repository.get_agent_by_id(VICTIM_ZERO_ID) == AGENTS[0]
+
+
+def test_reset__removal_error(error_raising_agent_repository):
+    with pytest.raises(RemovalError):
+        error_raising_agent_repository.reset()
diff --git a/vulture_allowlist.py b/vulture_allowlist.py
index 68a94a2db..ea46d5b2b 100644
--- a/vulture_allowlist.py
+++ b/vulture_allowlist.py
@@ -238,8 +238,9 @@ NetworkMap
 Arc.dst_machine
 IMitigationsRepository.get_mitigations
 IMitigationsRepository.save_mitigations
-IAgentRepository.save_agent
-IAgentRepository.get_agents
+IAgentRepository.upsert_agent
+IAgentRepository.get_agent_by_id
+IAgentRepository.get_running_agents
 agent
 IAttackRepository.get_attack_report
 IAttackRepository.save_attack_report