diff --git a/backend/app/api/agents.py b/backend/app/api/agents.py
index b1cf144..d34b637 100644
--- a/backend/app/api/agents.py
+++ b/backend/app/api/agents.py
@@ -1,17 +1,91 @@
 """Agents REST API.
 
-Endpoints for Agency agents (Supabase Auth; link via supabase_user_id).
+Full CRUD for agents resource.
 """
 
-from fastapi import APIRouter, Response, status
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from ..database import get_db
+from ..models import Agent
+from ..schemas import AgentCreate, AgentUpdate, Agent as AgentSchema
+from ..services import agents as agent_service
 
 router = APIRouter()
 
+# Helpers
+
+
+async def get_agent_or_404(agent_id: str, db: AsyncSession) -> Agent:
+    """
+    Reusable helper: looks up agent by ID
+    If not found, raise a 404 immediately
+    """
+    agent = await agent_service.get_agent(agent_id, db)
+    if not agent:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Agent with id '{agent_id}' not found.",
+        )
+    return agent
+
+
+# Endpoints
+
+
+@router.get("", response_model=list[AgentSchema])
+async def list_agents(db: AsyncSession = Depends(get_db)):
+    """
+    GET /api/agents
+    Returns list of all agents
+    """
+    return await agent_service.list_agents(db)
+
+
+@router.post("", response_model=AgentSchema, status_code=status.HTTP_201_CREATED)
+async def create_agent(agent: AgentCreate, db: AsyncSession = Depends(get_db)):
+    """
+    Creates a new agent.
+    """
+    if not await agent_service.validate_agency_exists(agent.agency_id, db):
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Agency with id '{agent.agency_id}' not found.",
+        )
+    return await agent_service.create_agent(agent, db)
+
+
+@router.get("/{agent_id}", response_model=AgentSchema)
+async def get_agent(agent_id: str, db: AsyncSession = Depends(get_db)):
+    """
+    Returns a single agent.
+    """
+    return await get_agent_or_404(agent_id, db)
+
+
+@router.put("/{agent_id}", response_model=AgentSchema)
+async def update_agent(
+    agent_id: str,
+    payload: AgentUpdate,
+    db: AsyncSession = Depends(get_db),
+):
+    """
+    Updates an existing agent.
+    """
+    agent = await get_agent_or_404(agent_id, db)
+    if "agency_id" in payload.model_dump(exclude_unset=True):
+        if not await agent_service.validate_agency_exists(payload.agency_id, db):
+            raise HTTPException(
+                status_code=status.HTTP_404_NOT_FOUND,
+                detail=f"Agency with id '{payload.agency_id}' not found.",
+            )
+    return await agent_service.update_agent(agent, payload, db)
+
 
-@router.get("")
-async def list_agents():
-    """List agents. Placeholder — implement with Agent model and schemas."""
-    return Response(
-        content="Not implemented — see docs/STARTER_BACKEND_GUIDE.md",
-        status_code=status.HTTP_501_NOT_IMPLEMENTED,
-    )
+@router.delete("/{agent_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_agent(agent_id: str, db: AsyncSession = Depends(get_db)):
+    """
+    Deletes an agent.
+    """
+    agent = await get_agent_or_404(agent_id, db)
+    await agent_service.delete_agent(agent, db)
diff --git a/backend/app/services/agents.py b/backend/app/services/agents.py
new file mode 100644
index 0000000..baa6265
--- /dev/null
+++ b/backend/app/services/agents.py
@@ -0,0 +1,81 @@
+"""Agents service."""
+
+from sqlalchemy import select
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from ..models import Agency, Agent
+from ..schemas import AgentCreate, AgentUpdate
+
+
+async def validate_agency_exists(agency_id: str, db: AsyncSession) -> bool:
+    """
+    Return True if the agency exists, False otherwise.
+    """
+    result = await db.execute(select(Agency).where(Agency.id == agency_id))
+    return result.scalar_one_or_none() is not None
+
+
+async def list_agents(db: AsyncSession) -> list[Agent]:
+    """
+    Return all agents ordered by last name, first name.
+    """
+    result = await db.execute(select(Agent).order_by(Agent.last_name, Agent.first_name))
+    return result.scalars().all()
+
+
+async def get_agent(agent_id: str, db: AsyncSession) -> Agent | None:
+    """
+    Return an agent by id, or None if not found.
+    """
+    result = await db.execute(select(Agent).where(Agent.id == agent_id))
+    return result.scalar_one_or_none()
+
+
+async def create_agent(payload: AgentCreate, db: AsyncSession) -> Agent:
+    """
+    Create and return a new agent.
+    """
+    db_agent = Agent(**payload.model_dump())
+    db.add(db_agent)
+    try:
+        await db.commit()
+    except IntegrityError as e:
+        await db.rollback()
+        raise ValueError(f"Unable to create agent: {str(e.orig)}") from e
+    await db.refresh(db_agent)
+    return db_agent
+
+
+async def update_agent(
+    agent: Agent,
+    payload: AgentUpdate,
+    db: AsyncSession,
+) -> Agent:
+    """
+    Update and return an existing agent.
+    """
+    update_data = payload.model_dump(exclude_unset=True)
+    if not update_data:
+        raise ValueError("No update fields were provided.")
+    for key, value in update_data.items():
+        setattr(agent, key, value)
+    try:
+        await db.commit()
+    except IntegrityError as e:
+        await db.rollback()
+        raise ValueError(f"Unable to update agent: {str(e.orig)}") from e
+    await db.refresh(agent)
+    return agent
+
+
+async def delete_agent(agent: Agent, db: AsyncSession) -> None:
+    """
+    Delete an agent permanently.
+    """
+    await db.delete(agent)
+    try:
+        await db.commit()
+    except IntegrityError as e:
+        await db.rollback()
+        raise ValueError(f"Unable to delete agent: {str(e.orig)}") from e