Custom GPTs & AI Agents
What It Does
Custom GPTs are purpose-built AI assistants you create within ChatGPT. Instead of starting every conversation with context about your business, a custom GPT comes pre-loaded with your specific instructions, knowledge, and personality. It knows your brand voice, your products, your processes, and your preferences — so every interaction starts from a position of understanding.
Think of it as creating a specialist AI assistant for a specific role: a customer FAQ bot that knows your product range, a sales assistant that understands your pricing and USPs, an onboarding tool that guides new employees through your processes, or a content creator that writes in your brand voice with your preferred style.
OpenAI’s GPT Builder makes this accessible without code. Describe what you want in plain language, upload reference documents, and configure the behaviour. Share it with your team or, if useful, publish it to OpenAI’s GPT Store.
Who It’s For
Businesses with repetitive AI tasks: If you find yourself giving ChatGPT the same instructions repeatedly (“write in our brand voice,” “reference our product catalogue,” “follow our response template”), a custom GPT eliminates that repetition.
Teams where multiple people use AI: A custom GPT ensures consistency. Everyone on your team gets the same quality output with the same context, rather than each person prompt-engineering independently.
Customer-facing applications: Build a GPT that can answer product questions, guide users through your services, or pre-qualify leads based on your criteria.
Not ideal for: One-off or varied AI tasks where the same context isn’t reused, businesses that only use AI occasionally, or applications requiring real-time data access from external systems (custom GPTs have limited integration capabilities).
UK-Specific Notes
Custom GPTs require a ChatGPT Plus subscription ($20/month, ~£16). Creating and using custom GPTs is included — no additional cost beyond the subscription.
For UK businesses, the most valuable custom GPTs incorporate UK-specific context: British English, UK regulations and legislation, UK market data, UK pricing norms, and UK customer expectations. Upload your UK-specific documents and instructions to make the GPT genuinely useful for your market.
Data privacy is a consideration. Information you upload to a custom GPT is processed by OpenAI. For sensitive business data — client information, financial details, proprietary processes — review OpenAI’s data usage policies. Team and Enterprise plans provide stronger privacy guarantees.
Published GPTs in the GPT Store are public. Keep internal-use GPTs private to protect your business knowledge and competitive advantage.
Key Features
Setup & Complexity
Moderate — Some setup required. The GPT Builder itself is simple — you describe what you want in conversation. The complexity lies in thinking clearly about what the GPT should know, how it should behave, and what documents to upload.
Budget 1–2 hours for a basic custom GPT. More complex GPTs with extensive knowledge bases and specific behaviour rules take a day to build and refine.
The key to a good custom GPT is iteration. Build a first version, test it extensively, identify gaps, and refine. Most GPTs need 3–5 rounds of refinement before they’re reliably useful.
Scoring Breakdown
| Criteria | Score | Why |
|---|---|---|
| Usefulness | 8/10 | Eliminates repetitive prompting and ensures consistent AI output |
| Ease of Use | 7/10 | Builder is intuitive but designing effective GPTs takes thought |
| Value | 7/10 | Included with ChatGPT Plus — no extra cost |
| UK Relevance | 6/10 | No UK-specific features — you add UK context yourself |
| AI Quality | 7/10 | GPT-4 intelligence with your specific context — powerful combination |
| Support | 6/10 | Limited documentation on GPT building best practices |
Pricing (UK)
| Plan | Price | Details |
|---|---|---|
| Included with ChatGPT Plus (~£16/month): | Create unlimited custom GPTs. No additional per-GPT charge. | |
| ChatGPT Team (~£20/user/month): | Share GPTs across your team with workspace management. | |
| ChatGPT Enterprise (Custom): | Advanced sharing controls, analytics, and security. |
How We’d Use It
Month 1: Identify your top 3 repetitive AI tasks. Build a custom GPT for the most common one — typically a content creator loaded with your brand voice guidelines and writing examples, or a customer FAQ bot with your product information. Test it thoroughly and refine the instructions.
Month 2: Build 2–3 more GPTs for different functions. A sales GPT that knows your pricing and USPs for drafting proposals. An HR GPT loaded with your employee handbook for answering policy questions. A meeting prep GPT that generates agendas and briefing notes from uploaded context.
Month 3: Roll out the GPTs to your team. Train everyone on which GPT to use for which task. Gather feedback on accuracy and gaps, and refine the knowledge bases. Track time saved compared to standard ChatGPT use with manual prompting.
Pros & Cons
✓ What’s Good
- Eliminates repetitive context-setting in every conversation
- Ensures consistent AI output across your team
- No-code builder makes creation accessible to non-technical users
- Knowledge upload lets you give the AI genuine expertise about your business
- Included with ChatGPT Plus — no extra cost
- Sharing features enable team-wide deployment
✗ What’s Not
- Knowledge retrieval isn’t always reliable — the GPT sometimes ignores uploaded documents
- 20-file upload limit restricts the depth of knowledge you can provide
- No analytics on GPT usage or performance
- Public GPTs in the Store expose your instructions to others
- Can’t access real-time external data without technical API configuration
- Quality depends heavily on how well you write the instructions
Alternatives
| Tool | Best For | UK Price | Our Score |
|---|---|---|---|
| Claude Projects | Claude-based custom AI with larger context window | Included with Claude Pro | 7.5/10 |
| Microsoft Copilot Studio | Enterprise custom AI assistants | Included with M365 Copilot | 6.5/10 |
| Botpress | Custom chatbots with more integration options | Free / ~£30/mo | 6/10 |
Our Verdict
Custom GPTs are one of the most practical applications of AI for UK SMEs. They take the general-purpose intelligence of ChatGPT and make it specific to your business — your knowledge, your voice, your processes. The no-code builder makes this accessible to anyone.
Buy if: You already use ChatGPT Plus and find yourself repeating the same context in conversations. A custom GPT saves time on every interaction and ensures consistency across your team.
Skip if: You don’t use AI regularly enough to justify building purpose-built tools, or your AI needs are too varied to benefit from pre-configured contexts.
Bottom line: Custom GPTs are the gateway to business-specific AI. They’re not revolutionary, but the practical time savings are real and immediate. Start with one GPT for your most common task and expand from there.
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