Custom GPTs and AI agents built for real work.

"Custom GPT" means two very different things depending on who you ask. OpenAI's Custom GPTs (built inside ChatGPT with the GPT Builder) are great for quick internal tools and personal assistants. Custom AI agents (built with the OpenAI, Anthropic or Google APIs) are full applications — branded, integrated with your systems, accessible to your customers, owned by you. We build both and we'll tell you upfront which one your problem actually needs.

When a Custom GPT is enough

If you want an internal tool — a brand-voice writing assistant, an SOP lookup bot, a proposal-drafting helper for your sales team — and everyone using it already has ChatGPT Plus or Enterprise, a Custom GPT is genuinely fine. You can configure instructions, upload knowledge files (PDFs, docs), enable web browsing and code interpreter, and add Actions to call external APIs. Builds typically take 1–2 weeks and cost £600–£2,500 done properly.

When you need a custom AI agent

You need a real custom agent when: you want to expose the AI to customers (not just internal staff with ChatGPT accounts), you need a branded UI rather than the ChatGPT interface, you have a knowledge base larger than the Custom GPT 20-file limit, you need full audit logging or compliance controls, you want to use Claude or Gemini instead of GPT, or you need fine-grained control over costs at scale. Almost every production customer-facing AI is a custom agent, not a Custom GPT.

Our build approach

We start with a prompt and a clear evaluation framework — what does "good" look like, what queries should it answer well, what should it refuse. Then we layer in retrieval (vector search over your real content), tool calling (real API integrations into your CRM, calendar, database), guardrails (output validation, refusal handling, escalation paths), and observability (every conversation logged, every tool call traced, costs tracked per session). The UI is the last step, not the first.

Model and framework choices

For most production agents we recommend a model-agnostic stack: LangChain or LlamaIndex for orchestration, Pinecone or Supabase pgvector for retrieval, OpenAI / Anthropic / Google as the LLM (often two of them, with fallback). This means you're not locked to one vendor's pricing or roadmap. For lighter use cases we'll use OpenAI's Assistants API or Anthropic's Tools API directly — less flexibility, faster to ship.

Pricing tiers

Custom GPT setup (£600–£2,500): properly configured GPT with knowledge files and Actions for one specific use case. Production AI agent (£3,500–£12,000): custom API-based agent with RAG, integrations, branded UI and basic observability. Enterprise agent (£12,000–£40,000): multi-agent orchestration, advanced tooling, evaluation pipelines, SSO, audit logging. Ongoing maintenance from £300/month covers prompt tuning, content updates and model upgrades as the AI landscape evolves.

What we won't do

We won't build agents that make autonomous high-stakes decisions without human review (legal advice, medical guidance, hiring decisions, financial trading). We won't build "agents" that are really brittle prompt chains pretending to be intelligent. And we won't lock you into our infrastructure — every project hands over with full code ownership, documentation and the ability to run it yourself.