diff --git a/ra_aid/server/api_v1_spawn_agent.py b/ra_aid/server/api_v1_spawn_agent.py
new file mode 100644
index 0000000..cb247a0
--- /dev/null
+++ b/ra_aid/server/api_v1_spawn_agent.py
@@ -0,0 +1,213 @@
+"""API router for spawning an RA.Aid agent."""
+
+import threading
+import logging
+from typing import Dict, Any, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel, Field
+
+from ra_aid.database.repositories.session_repository import SessionRepository, get_session_repository
+from ra_aid.database.connection import DatabaseManager
+from ra_aid.database.repositories.session_repository import SessionRepositoryManager
+from ra_aid.database.repositories.key_fact_repository import KeyFactRepositoryManager
+from ra_aid.database.repositories.key_snippet_repository import KeySnippetRepositoryManager
+from ra_aid.database.repositories.human_input_repository import HumanInputRepositoryManager
+from ra_aid.database.repositories.research_note_repository import ResearchNoteRepositoryManager
+from ra_aid.database.repositories.related_files_repository import RelatedFilesRepositoryManager
+from ra_aid.database.repositories.trajectory_repository import TrajectoryRepositoryManager
+from ra_aid.database.repositories.work_log_repository import WorkLogRepositoryManager
+from ra_aid.database.repositories.config_repository import ConfigRepositoryManager
+from ra_aid.env_inv_context import EnvInvManager
+from ra_aid.env_inv import EnvDiscovery
+from ra_aid.database import ensure_migrations_applied
+
+# Create logger
+logger = logging.getLogger(__name__)
+
+# Create API router
+router = APIRouter(
+    prefix="/v1/spawn-agent",
+    tags=["agent"],
+    responses={
+        status.HTTP_422_UNPROCESSABLE_ENTITY: {"description": "Validation error"},
+        status.HTTP_500_INTERNAL_SERVER_ERROR: {"description": "Agent spawn error"},
+    },
+)
+
+class SpawnAgentRequest(BaseModel):
+    """
+    Pydantic model for agent spawn requests.
+    
+    This model provides validation for spawning a new agent.
+    
+    Attributes:
+        message: The message or task for the agent to process
+        research_only: Whether to use research-only mode (default: False)
+        expert_enabled: Whether to enable expert assistance (default: True)
+        web_research_enabled: Whether to enable web research (default: False)
+    """
+    message: str = Field(
+        description="The message or task for the agent to process"
+    )
+    research_only: bool = Field(
+        default=False,
+        description="Whether to use research-only mode"
+    )
+    expert_enabled: bool = Field(
+        default=True,
+        description="Whether to enable expert assistance"
+    )
+    web_research_enabled: bool = Field(
+        default=False,
+        description="Whether to enable web research"
+    )
+
+class SpawnAgentResponse(BaseModel):
+    """
+    Pydantic model for agent spawn responses.
+    
+    This model defines the response format for the spawn-agent endpoint.
+    
+    Attributes:
+        session_id: The ID of the created session
+    """
+    session_id: str = Field(
+        description="The ID of the created session"
+    )
+    
+    
+def get_repository() -> SessionRepository:
+    """
+    Get the SessionRepository instance.
+    
+    This function is used as a FastAPI dependency and can be overridden
+    in tests using dependency_overrides.
+    
+    Returns:
+        SessionRepository: The repository instance
+    """
+    return get_session_repository()
+
+def run_agent_thread(
+    message: str,
+    session_id: str,
+    research_only: bool = False,
+    expert_enabled: bool = True,
+    web_research_enabled: bool = False,
+):
+    """
+    Run a research agent in a separate thread with proper repository initialization.
+    
+    Args:
+        message: The message or task for the agent to process
+        session_id: The ID of the session to associate with this agent
+        research_only: Whether to use research-only mode
+        expert_enabled: Whether to enable expert assistance
+        web_research_enabled: Whether to enable web research
+    """
+    try:
+        logger.info(f"Starting agent thread for session {session_id}")
+        
+        # Initialize environment discovery
+        env_discovery = EnvDiscovery()
+        env_discovery.discover()
+        env_data = env_discovery.format_markdown()
+        
+        # Apply any pending database migrations
+        try:
+            migration_result = ensure_migrations_applied()
+            if not migration_result:
+                logger.warning("Database migrations failed but execution will continue")
+        except Exception as e:
+            logger.error(f"Database migration error: {str(e)}")
+        
+        # Initialize empty config dictionary
+        config = {}
+        
+        # Initialize database connection and repositories
+        with DatabaseManager() as db, \
+             SessionRepositoryManager(db) as session_repo, \
+             KeyFactRepositoryManager(db) as key_fact_repo, \
+             KeySnippetRepositoryManager(db) as key_snippet_repo, \
+             HumanInputRepositoryManager(db) as human_input_repo, \
+             ResearchNoteRepositoryManager(db) as research_note_repo, \
+             RelatedFilesRepositoryManager() as related_files_repo, \
+             TrajectoryRepositoryManager(db) as trajectory_repo, \
+             WorkLogRepositoryManager() as work_log_repo, \
+             ConfigRepositoryManager(config) as config_repo, \
+             EnvInvManager(env_data) as env_inv:
+            
+            # Import here to avoid circular imports
+            from ra_aid.__main__ import run_research_agent
+            
+            # Run the research agent
+            run_research_agent(
+                base_task_or_query=message,
+                model=None,  # Use default model
+                expert_enabled=expert_enabled,
+                research_only=research_only,
+                hil=False,  # No human-in-the-loop for API
+                web_research_enabled=web_research_enabled,
+                thread_id=session_id
+            )
+            
+            logger.info(f"Agent completed for session {session_id}")
+    except Exception as e:
+        logger.error(f"Error in agent thread for session {session_id}: {str(e)}")
+
+@router.post(
+    "",
+    response_model=SpawnAgentResponse,
+    status_code=status.HTTP_201_CREATED,
+    summary="Spawn agent",
+    description="Spawn a new RA.Aid agent to process a message or task",
+)
+async def spawn_agent(
+    request: SpawnAgentRequest,
+    repo: SessionRepository = Depends(get_repository),
+) -> SpawnAgentResponse:
+    """
+    Spawn a new RA.Aid agent to process a message or task.
+    
+    Args:
+        request: Request body with message and agent configuration
+        repo: SessionRepository dependency injection
+        
+    Returns:
+        SpawnAgentResponse: Response with session ID
+        
+    Raises:
+        HTTPException: With a 500 status code if there's an error spawning the agent
+    """
+    try:
+        # Create a new session
+        metadata = {
+            "agent_type": "research-only" if request.research_only else "research",
+            "expert_enabled": request.expert_enabled,
+            "web_research_enabled": request.web_research_enabled,
+        }
+        session = repo.create_session(metadata=metadata)
+        
+        # Start the agent thread
+        thread = threading.Thread(
+            target=run_agent_thread,
+            args=(
+                request.message,
+                str(session.id),
+                request.research_only,
+                request.expert_enabled,
+                request.web_research_enabled,
+            )
+        )
+        thread.daemon = True  # Thread will terminate when main process exits
+        thread.start()
+        
+        # Return the session ID
+        return SpawnAgentResponse(session_id=str(session.id))
+    except Exception as e:
+        logger.error(f"Error spawning agent: {str(e)}")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Error spawning agent: {str(e)}",
+        )
\ No newline at end of file
diff --git a/ra_aid/server/server.py b/ra_aid/server/server.py
index d44f5c4..45b221f 100644
--- a/ra_aid/server/server.py
+++ b/ra_aid/server/server.py
@@ -34,6 +34,7 @@ from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
 
 from ra_aid.server.api_v1_sessions import router as sessions_router
+from ra_aid.server.api_v1_spawn_agent import router as spawn_agent_router
 
 app = FastAPI(
     title="RA.Aid API",
@@ -52,6 +53,7 @@ app.add_middleware(
 
 # Include API routers
 app.include_router(sessions_router)
+app.include_router(spawn_agent_router)
 
 # Setup templates and static files directories
 CURRENT_DIR = Path(__file__).parent
diff --git a/tests/ra_aid/server/test_api_v1_spawn_agent.py b/tests/ra_aid/server/test_api_v1_spawn_agent.py
new file mode 100644
index 0000000..a440693
--- /dev/null
+++ b/tests/ra_aid/server/test_api_v1_spawn_agent.py
@@ -0,0 +1,134 @@
+"""
+Tests for the Spawn Agent API v1 endpoint.
+
+This module contains tests for the spawn-agent API endpoint in ra_aid/server/api_v1_spawn_agent.py.
+It tests the creation of agent threads and session handling for the spawn-agent endpoint.
+"""
+
+import pytest
+import threading
+from unittest.mock import MagicMock
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from ra_aid.server.api_v1_spawn_agent import router, get_repository
+from ra_aid.database.pydantic_models import SessionModel
+import datetime
+import ra_aid.server.api_v1_spawn_agent
+
+
+@pytest.fixture
+def mock_session():
+    """Return a mock session for testing."""
+    return SessionModel(
+        id=123,
+        created_at=datetime.datetime(2025, 1, 1, 0, 0, 0),
+        updated_at=datetime.datetime(2025, 1, 1, 0, 0, 0),
+        start_time=datetime.datetime(2025, 1, 1, 0, 0, 0),
+        command_line="ra-aid test",
+        program_version="1.0.0",
+        machine_info={"agent_type": "research", "expert_enabled": True, "web_research_enabled": False}
+    )
+
+
+@pytest.fixture
+def mock_thread():
+    """Create a mock thread that does nothing when started."""
+    mock = MagicMock()
+    mock.daemon = True
+    return mock
+
+
+@pytest.fixture
+def mock_repository(mock_session):
+    """Create a mock repository for testing."""
+    mock_repo = MagicMock()
+    mock_repo.create_session.return_value = mock_session
+    return mock_repo
+
+
+@pytest.fixture
+def client(mock_repository, mock_thread, monkeypatch):
+    """Set up a test client with mocked dependencies."""
+    # Create FastAPI app with router
+    app = FastAPI()
+    app.include_router(router)
+    
+    # Override the dependency to use our mock repository
+    app.dependency_overrides[get_repository] = lambda: mock_repository
+    
+    # Mock run_agent_thread to be a no-op
+    monkeypatch.setattr(
+        "ra_aid.server.api_v1_spawn_agent.run_agent_thread", 
+        lambda *args, **kwargs: None
+    )
+    
+    # Mock threading.Thread to return our mock thread
+    def mock_thread_constructor(*args, **kwargs):
+        mock_thread.target = kwargs.get('target')
+        mock_thread.args = kwargs.get('args')
+        mock_thread.daemon = kwargs.get('daemon', False)
+        return mock_thread
+    
+    monkeypatch.setattr(
+        ra_aid.server.api_v1_spawn_agent,
+        "threading",
+        MagicMock(Thread=mock_thread_constructor)
+    )
+    
+    client = TestClient(app)
+    
+    # Add mocks to client for test access
+    client.mock_repo = mock_repository
+    client.mock_thread = mock_thread
+    
+    yield client
+    
+    # Clean up the dependency override
+    app.dependency_overrides.clear()
+
+
+def test_spawn_agent(client, mock_repository, mock_thread):
+    """Test spawning an agent with valid parameters."""
+    # Create the request payload
+    payload = {
+        "message": "Test task for the agent",
+        "research_only": False,
+        "expert_enabled": True,
+        "web_research_enabled": False
+    }
+    
+    # Send the request
+    response = client.post("/v1/spawn-agent", json=payload)
+    
+    # Verify response
+    assert response.status_code == 201
+    assert response.json() == {"session_id": "123"}
+    
+    # Verify session creation
+    mock_repository.create_session.assert_called_once()
+    
+    # Verify thread was created with correct args
+    assert mock_thread.args == ("Test task for the agent", "123", False, True, False)
+    assert mock_thread.daemon is True
+    
+    # Verify thread.start was called
+    mock_thread.start.assert_called_once()
+
+
+def test_spawn_agent_missing_message(client):
+    """Test spawning an agent with missing required message parameter."""
+    # Create a request payload missing the required message
+    payload = {
+        "research_only": False,
+        "expert_enabled": True,
+        "web_research_enabled": False
+    }
+    
+    # Send the request
+    response = client.post("/v1/spawn-agent", json=payload)
+    
+    # Verify response indicates validation error
+    assert response.status_code == 422
+    error_detail = response.json().get("detail", [])
+    assert any("message" in error.get("loc", []) for error in error_detail)
\ No newline at end of file