7 min read
Building AI Agents: From Simple to Sophisticated
AI agents are systems that can take actions autonomously to achieve goals. Today I’m exploring how to build agents from simple tool-using assistants to complex autonomous systems.
Agent Architecture Levels
Level 1: Tool-Augmented LLM
└── LLM + function calling
Level 2: ReAct Agent
└── Reasoning + Acting loop
Level 3: Planning Agent
└── Task decomposition + execution
Level 4: Multi-Agent System
└── Specialized agents collaborating
Level 5: Autonomous Agent
└── Self-directed goal pursuitLevel 1: Tool-Augmented LLM
from openai import AzureOpenAI
import json
client = AzureOpenAI(
api_version="2024-05-01-preview",
azure_endpoint=os.environ["AZURE_OPENAI_ENDPOINT"],
api_key=os.environ["AZURE_OPENAI_KEY"]
)
# Define tools
tools = [
{
"type": "function",
"function": {
"name": "search_documents",
"description": "Search internal documents",
"parameters": {
"type": "object",
"properties": {
"query": {"type": "string", "description": "Search query"}
},
"required": ["query"]
}
}
},
{
"type": "function",
"function": {
"name": "run_sql",
"description": "Execute SQL query on analytics database",
"parameters": {
"type": "object",
"properties": {
"query": {"type": "string", "description": "SQL query"}
},
"required": ["query"]
}
}
}
]
def tool_augmented_chat(user_message: str) -> str:
messages = [
{"role": "system", "content": "You help users with data analysis. Use tools when needed."},
{"role": "user", "content": user_message}
]
response = client.chat.completions.create(
model="gpt-4o",
messages=messages,
tools=tools,
tool_choice="auto"
)
# Handle tool calls
while response.choices[0].message.tool_calls:
tool_calls = response.choices[0].message.tool_calls
messages.append(response.choices[0].message)
for tool_call in tool_calls:
result = execute_tool(tool_call.function.name, tool_call.function.arguments)
messages.append({
"role": "tool",
"tool_call_id": tool_call.id,
"content": json.dumps(result)
})
response = client.chat.completions.create(
model="gpt-4o",
messages=messages,
tools=tools
)
return response.choices[0].message.content
def execute_tool(name: str, arguments: str) -> dict:
args = json.loads(arguments)
if name == "search_documents":
return search_documents(args["query"])
elif name == "run_sql":
return run_sql(args["query"])
return {"error": "Unknown tool"}Level 2: ReAct Agent
class ReActAgent:
"""Reasoning and Acting agent pattern."""
def __init__(self, client, tools: list):
self.client = client
self.tools = {t["function"]["name"]: t for t in tools}
self.max_iterations = 10
def run(self, goal: str) -> str:
system_prompt = """You are an AI agent that solves problems step by step.
For each step:
1. Thought: Reason about what to do next
2. Action: Choose a tool and parameters
3. Observation: Review the result
4. Repeat until you have the answer
When you have the final answer, respond with:
Final Answer: [your answer]
"""
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": f"Goal: {goal}"}
]
for i in range(self.max_iterations):
response = self.client.chat.completions.create(
model="gpt-4o",
messages=messages,
tools=list(self.tools.values()),
tool_choice="auto"
)
assistant_message = response.choices[0].message
messages.append(assistant_message)
# Check for final answer
if assistant_message.content and "Final Answer:" in assistant_message.content:
return assistant_message.content.split("Final Answer:")[-1].strip()
# Execute tool calls
if assistant_message.tool_calls:
for tool_call in assistant_message.tool_calls:
result = self._execute_tool(
tool_call.function.name,
tool_call.function.arguments
)
messages.append({
"role": "tool",
"tool_call_id": tool_call.id,
"content": json.dumps(result)
})
return "Max iterations reached without final answer"
def _execute_tool(self, name: str, arguments: str) -> dict:
# Tool execution logic
passLevel 3: Planning Agent
class PlanningAgent:
"""Agent that creates and executes plans."""
def __init__(self, client, tools: list):
self.client = client
self.tools = tools
def solve(self, goal: str) -> str:
# Step 1: Create a plan
plan = self._create_plan(goal)
print(f"Plan created with {len(plan)} steps")
# Step 2: Execute plan
results = []
for i, step in enumerate(plan):
print(f"Executing step {i+1}: {step['description']}")
result = self._execute_step(step, results)
results.append(result)
# Step 3: Synthesize results
return self._synthesize(goal, plan, results)
def _create_plan(self, goal: str) -> list:
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": """Create a step-by-step plan to achieve the goal.
Return JSON array of steps:
[
{"step": 1, "description": "...", "tool": "tool_name", "depends_on": []},
{"step": 2, "description": "...", "tool": "tool_name", "depends_on": [1]}
]"""
},
{"role": "user", "content": f"Goal: {goal}\n\nAvailable tools: {self._tool_descriptions()}"}
],
response_format={"type": "json_object"}
)
return json.loads(response.choices[0].message.content)["steps"]
def _execute_step(self, step: dict, previous_results: list) -> dict:
# Get context from dependent steps
context = ""
for dep in step.get("depends_on", []):
context += f"\nResult from step {dep}: {previous_results[dep-1]}"
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": f"Execute this step: {step['description']}\nContext: {context}"
}
],
tools=[t for t in self.tools if t["function"]["name"] == step.get("tool")],
tool_choice="auto"
)
# Execute any tool calls and return result
return self._handle_response(response)
def _synthesize(self, goal: str, plan: list, results: list) -> str:
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": "Synthesize the results to answer the original goal."
},
{
"role": "user",
"content": f"Goal: {goal}\n\nPlan and results:\n{json.dumps(list(zip(plan, results)), indent=2)}"
}
]
)
return response.choices[0].message.contentLevel 4: Multi-Agent System
from dataclasses import dataclass
from typing import Optional
from enum import Enum
class AgentRole(Enum):
RESEARCHER = "researcher"
ANALYST = "analyst"
WRITER = "writer"
REVIEWER = "reviewer"
@dataclass
class AgentMessage:
from_agent: AgentRole
to_agent: Optional[AgentRole]
content: str
artifacts: Optional[dict] = None
class MultiAgentSystem:
"""Coordinated multi-agent system."""
def __init__(self, client):
self.client = client
self.agents = self._create_agents()
self.message_queue = []
def _create_agents(self) -> dict:
return {
AgentRole.RESEARCHER: {
"instructions": "You research topics and gather information.",
"tools": ["search_web", "search_docs"]
},
AgentRole.ANALYST: {
"instructions": "You analyze data and find patterns.",
"tools": ["run_sql", "create_chart"]
},
AgentRole.WRITER: {
"instructions": "You write clear, professional content.",
"tools": ["format_document"]
},
AgentRole.REVIEWER: {
"instructions": "You review content for accuracy and quality.",
"tools": ["fact_check"]
}
}
async def execute_workflow(self, task: str) -> str:
# Coordinator determines workflow
workflow = await self._plan_workflow(task)
results = {}
for step in workflow:
agent_role = AgentRole(step["agent"])
result = await self._run_agent(
agent_role,
step["task"],
{k: results[k] for k in step.get("inputs", [])}
)
results[step["id"]] = result
return results.get("final", "")
async def _plan_workflow(self, task: str) -> list:
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": f"""Plan a workflow for this task using available agents: {[a.value for a in AgentRole]}.
Return JSON:
{{
"steps": [
{{"id": "step1", "agent": "researcher", "task": "...", "inputs": []}},
{{"id": "step2", "agent": "analyst", "task": "...", "inputs": ["step1"]}},
{{"id": "final", "agent": "writer", "task": "...", "inputs": ["step2"]}}
]
}}"""
},
{"role": "user", "content": task}
],
response_format={"type": "json_object"}
)
return json.loads(response.choices[0].message.content)["steps"]
async def _run_agent(self, role: AgentRole, task: str, inputs: dict) -> str:
agent_config = self.agents[role]
messages = [
{"role": "system", "content": agent_config["instructions"]},
{
"role": "user",
"content": f"Task: {task}\n\nInputs: {json.dumps(inputs)}"
}
]
response = self.client.chat.completions.create(
model="gpt-4o",
messages=messages
)
return response.choices[0].message.contentLevel 5: Autonomous Agent
class AutonomousAgent:
"""Self-directed agent with goals and reflection."""
def __init__(self, client, name: str, goals: list):
self.client = client
self.name = name
self.goals = goals
self.memory = []
self.task_queue = []
async def run(self, max_iterations: int = 50):
for i in range(max_iterations):
# Reflect on progress
reflection = await self._reflect()
if reflection["goals_complete"]:
print(f"All goals achieved after {i} iterations")
return self._get_final_output()
# Plan next action
action = await self._plan_next_action(reflection)
# Execute action
result = await self._execute_action(action)
# Store in memory
self.memory.append({
"iteration": i,
"reflection": reflection,
"action": action,
"result": result
})
# Check for blockers
if await self._is_blocked(result):
await self._handle_blocker(result)
async def _reflect(self) -> dict:
recent_memory = self.memory[-10:] if len(self.memory) > 10 else self.memory
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": f"""Reflect on progress toward goals: {self.goals}
Return JSON:
{{
"goals_complete": false,
"progress": {{"goal_1": 0.5, "goal_2": 0.2}},
"blockers": [],
"next_priority": "goal_1"
}}"""
},
{
"role": "user",
"content": f"Recent activity: {json.dumps(recent_memory)}"
}
],
response_format={"type": "json_object"}
)
return json.loads(response.choices[0].message.content)
async def _plan_next_action(self, reflection: dict) -> dict:
response = self.client.chat.completions.create(
model="gpt-4o",
messages=[
{
"role": "system",
"content": """Plan the next action to make progress.
Return JSON:
{
"action": "action_name",
"parameters": {},
"reasoning": "why this action"
}"""
},
{
"role": "user",
"content": f"Reflection: {json.dumps(reflection)}\nGoals: {self.goals}"
}
],
response_format={"type": "json_object"}
)
return json.loads(response.choices[0].message.content)Best Practices
- Start simple - Begin with Level 1, add complexity as needed
- Clear boundaries - Define what agents can and cannot do
- Human in the loop - Critical decisions should involve humans
- Logging everything - Essential for debugging and auditing
- Fail safely - Agents should fail gracefully
What’s Next
Tomorrow I’ll cover agent orchestration patterns in more depth.