Melony

Should you build a chat UI for your hosted agent? A build-vs-buy checklist

Before building a front end for an OpenAI or Claude Managed Agent, check what a team chat really needs, from auth and sharing to key handling, and what it costs to own.

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Hosted agent platforms like the OpenAI Agents API and Claude Managed Agents make the agent easy: you define the model, instructions and tools, and the platform runs sessions for you. What they don’t give you is a place for your team to use that agent together.

So most teams hit the same question: build a front end, or use one?

What a team chat for an agent actually needs

It’s more than a text box and a streaming response. Count the pieces:

  1. Sign-in for people who don’t have platform accounts.
  2. Membership per agent: who can use it, who can invite, who owns the key.
  3. A server-side proxy so the API key never reaches a browser.
  4. Streaming of text, and ideally tool activity and reasoning summaries.
  5. Chat history per person. Neither platform tracks which user owns a session, so you need your own index.
  6. Private and shared chats, with clear rules about who can see, unshare and delete.
  7. Usage limits enforced on the server, not just in the UI.
  8. Platform quirks: environments and vaults on Claude Managed Agents, the hosted sandbox and Vault on OpenAI, and tool calls that pause for approval.

Each is small. Together they’re a product you’ll maintain as both platforms evolve.

Build it when

  • The chat is part of a customer-facing product with its own brand, auth and billing.
  • You need a custom UI for the agent’s output, like forms, dashboards or approvals.
  • You already run a web app where the agent naturally belongs.

Use a hosted chat when

  • The users are your own team: support, ops, sales, research.
  • You want them chatting today, not after a sprint.
  • You’d rather not own auth, session tenancy and key handling.

That’s the job Melony does: connect an agent from the OpenAI Agents API or Claude Managed Agents with its API key, invite teammates by email, and they chat in a hosted UI. The key stays server-side, chats are private by default, and conversations stay on the platform. It’s free, with up to three teammates per agent.

A quick decision test

Ask: “Would our users notice if the chat UI came from someone else?” If the answer is no, because they just want to use the agent, don’t build it. Spend that time on the agent.

Next: share an OpenAI agent or share a Claude Managed Agent.

Frequently asked questions

What does a team chat UI for an AI agent need?

At minimum sign-in, per-agent membership, streaming replies, chat history per person, private and shared chats, server-side API key handling, usage limits and a way to show tool activity.

When does it make sense to build your own agent front end?

When the chat is part of a customer-facing product with its own design, auth and billing. For internal teams using an agent you already built, a hosted chat is usually faster and cheaper to run.

Give your team a shared front door to your agent.

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