Custom AI Agent Development for Business

I build AI agents that go beyond chatbots -- autonomous systems that plan, reason, use tools, and take actions to achieve business goals. From customer support agents that actually resolve issues to operations agents that process documents and update systems.

01 / OVERVIEW

What Are AI Agents and Why Your Business Needs One

A chatbot answers questions. An AI agent gets things done. The difference is fundamental: an agent can plan a sequence of steps, use tools (APIs, databases, search), take actions in external systems, and adapt its approach based on results. It does not just respond -- it works.

Imagine an AI that receives a customer complaint, looks up the order in your system, checks the return policy, processes the refund, sends a confirmation email, and updates the CRM -- all autonomously. Or an agent that monitors your competitors' pricing, generates a report, and alerts your team when action is needed. These are not science fiction scenarios -- they are production-ready solutions I build today.

I am Kirill Strelnikov, a freelance AI engineer based in Barcelona. I specialize in building custom AI agents using LangChain, LangGraph, OpenAI, and Claude. AI agents represent the next evolution of business automation -- and early adopters are gaining a significant competitive advantage. For simpler conversational AI needs, see my AI chatbot development service.

02 / WHAT I BUILD

Types of AI Agents I Build

Customer-Facing Agents

Support agents that resolve issues end-to-end (refunds, cancellations, account changes). Sales agents that qualify leads, check availability, and book meetings. Onboarding agents that guide new users through setup with personalized steps.

Operations Agents

Document processing agents that extract, validate, and route data from invoices, contracts, and forms. Data analysis agents that query databases and generate insights. Monitoring agents that watch for anomalies and trigger alerts.

Research & Strategy Agents

Market research agents that gather and synthesize competitive intelligence. Content generation agents that produce drafts based on your brand guidelines. Code review agents that analyze pull requests and suggest improvements.

03 / TECHNOLOGY

AI Agent Tech Stack

Building reliable AI agents requires more than calling an API. It requires orchestration frameworks, tool management, memory systems, and robust error handling.

LangChain LangGraph OpenAI API Claude API Python Django FastAPI PostgreSQL pgvector Redis Celery Docker Tool Calling Function Calling RAG Vector Search

Agent framework: LangChain and LangGraph provide the orchestration layer -- planning loops, tool selection, memory management, and state machines that control agent behavior. The agent reasons about which tools to use, in what order, and how to handle unexpected results.

Tool system: Each agent is equipped with custom tools -- functions that interact with your APIs, databases, email systems, CRMs, and file storage. Tools are type-safe, logged, and rate-limited. The agent selects and combines tools dynamically based on the task.

Memory and context: Agents maintain short-term (conversation) and long-term (persistent) memory. RAG with vector search provides access to your knowledge base. This means agents improve over time and maintain context across interactions.

04 / PROCESS

How I Build Your AI Agent

01

Use Case Discovery & Agent Design

I analyze the task you want to automate, identify the tools the agent needs, define success criteria, and design the agent's reasoning flow. This phase produces a clear architecture document with a fixed-price estimate.

02

Architecture & Tool Definition

I design the agent's tool set, state machine, memory architecture, and error handling strategy. Each tool is specified with inputs, outputs, and side effects. You approve the design before development starts.

03

Agent Development & Training

I build the agent iteratively -- starting with core tools and basic reasoning, then adding complexity. Prompt engineering ensures the agent reasons correctly about when and how to use each tool. Weekly demos with real scenarios.

04

Testing with Real Scenarios

Comprehensive testing with production-like scenarios. I evaluate reasoning quality, tool selection accuracy, error recovery, and edge case handling. The agent is tested against adversarial inputs to ensure safety and reliability.

05

Deployment & Continuous Improvement

Production deployment with monitoring for reasoning quality, tool usage patterns, and success rates. I set up feedback loops so the agent improves based on real usage. Ongoing optimization packages available.

05 / CASE STUDIES

AI Agent Projects I Have Delivered

Multi-Model AI Aggregator with Autonomous Routing

Built a Telegram-based AI system that autonomously routes user requests to the optimal AI model (text, image, video generation). The system manages model selection, handles billing, processes concurrent requests through task queues, and scales automatically. Reached 500 paying users in 3 months with minimal manual intervention.

PythonOpenAIMulti-ModelCeleryRedisAutonomous Routing

AI-Powered Product Recommendation Agent

Built an agent for an e-commerce platform that understands customer preferences through conversation, searches the product catalog, generates personalized recommendations, and handles follow-up questions. The agent uses RAG to ground responses in actual product data and adapts its recommendations based on conversation context.

DjangoOpenAIRAGProduct CatalogRecommendation Engine
06 / WHO THIS IS FOR

Who This Service Is For

AI agents are the highest-impact AI investment a business can make in 2026. Book a free consultation to explore what an agent can do for your business.

07 / PRICING

AI Agent Development Pricing

Transparent pricing based on agent complexity. All prices include development, tool building, testing, deployment, documentation, and post-launch support.

Task-Specific Agent
€3,000 / from
Single-purpose autonomous agent
  • One specific task automated
  • 2-3 custom tools
  • Conversation memory
  • Error handling and logging
  • 2-4 weeks delivery
  • 30 days post-launch support
Enterprise Agent System
€12,000 / from
Multi-agent architecture
  • Multiple specialized agents
  • Agent orchestration layer
  • Custom tool ecosystem
  • Advanced monitoring and analytics
  • Human-in-the-loop workflows
  • 8-12 weeks delivery
  • 60 days post-launch support

Need a custom scope? Get in touch for a tailored proposal within 24 hours.

Frequently Asked Questions

What is an AI agent and how is it different from a chatbot?
A chatbot responds to messages within a conversation. An AI agent plans, reasons, uses tools, and takes autonomous actions to achieve goals. An agent can search databases, call APIs, process documents, send emails, update CRMs, and chain multiple steps together -- all without human intervention. Think of a chatbot as a receptionist and an agent as an employee who gets things done.
What can AI agents do for my business?
AI agents can handle customer support (resolving issues end-to-end), qualify and nurture leads, process documents and extract data, generate reports, monitor competitors, manage inventory, automate research, and orchestrate complex workflows across multiple systems. Any knowledge work that follows patterns can be delegated to an AI agent.
Which AI models do you use for agent development?
I primarily use OpenAI GPT-4 and Anthropic Claude for their strong reasoning and tool-use capabilities. The agent framework is built with LangChain and LangGraph. The architecture is model-agnostic, so you can switch models as better options become available without rebuilding the agent.
How long does it take to build a custom AI agent?
A task-specific agent takes 2-4 weeks. A multi-step agent with multiple tools and memory requires 4-6 weeks. Enterprise agent systems with multi-agent architecture take 8-12 weeks. Every project includes a discovery phase where I provide a detailed timeline and fixed-price estimate before any development begins.
How much does AI agent development cost?
A task-specific agent starts from EUR 3,000. Multi-step agent platforms cost from EUR 6,000. Enterprise multi-agent systems start from EUR 12,000. I provide fixed-price estimates after the discovery phase. The cost depends on the number of tools, complexity of reasoning, and number of integration points.
08 / YOUR DEVELOPER

About Kirill Strelnikov

Kirill Strelnikov is a freelance AI engineer based in Barcelona, Spain. He specializes in AI agent development, building autonomous systems with LangChain, LangGraph, OpenAI, and Claude. He has delivered over 15 commercial AI projects including multi-model AI platforms, intelligent chatbots, and automated business systems for clients across Europe.

He works with fixed-price contracts. Communication in English, Spanish, and Russian.

Learn more on the about page or explore the full portfolio.

Ready to Build Your AI Agent?

Tell Kirill about the task you want to automate. He will design an agent architecture, estimate the timeline, and give you a fixed price -- within 24 hours. Free consultation.

Book a free AI agent consultation

Recommended Reading

AI Agents for Business: What They Are and How to Use Them How to Build a Custom AI Chatbot for Your Business AI Chatbots by Industry