Set up the hosted Chat UI for your thunk
The hosted Chat UI is a ready-made chat page for your thunk. When your workflow has a conversation input, Thunk.AI hosts a chat app for it automatically — end users open a link, type a message, and the AI agent replies, all backed by the same workflow work item the agent already runs.
Use the hosted Chat UI when you want people to talk to your thunk without building anything yourself. If you instead need to embed chat inside your own website, mobile app, or portal, use the conversational REST API — the hosted Chat UI and the REST API run on the same conversation.
Precondition. The workflow must have exactly one input property whose type is Conversation. That property is the chat channel for each work item. Without it, the hosted Chat UI stays disabled.
Two ways to build a chat-based thunk
There are two ways to create a thunk that uses the hosted Chat UI:
Create a Chat App — on the My Thunks page, click New Chat App. This opens a guided wizard that walks you through defining your chat app's goal, workflow, and connections. The wizard creates a thunk with a conversation input already configured, so the Chat UI is ready to use as soon as the thunk is built.
Add a conversation property to any workflow — if you already have a thunk or prefer to set things up manually, add a single input property of type Conversation to your workflow. Once added, the Chat UI turns on for that thunk.
Both approaches produce the same result: a thunk whose workflow has exactly one conversation input, which enables the hosted Chat UI.
Configure the conversation property
In the thunk designer, open the workflow structure and confirm there is exactly one input property whose type is Conversation (often named EndUserConvo). This is the property the running workflow reads the back-and-forth from, and it is what turns on the chat app.
Open that property to control what the AI and end users can do in the chat:
AI file attachments — when enabled, the AI agent can attach files to its replies.
User file attachments — when enabled (the default), end users can attach files to their messages. When disabled, the attach control is hidden.
Form responses — when enabled, the AI agent can attach a short form to a message, for when your step's instructions ask it to collect structured answers (for example "ask the customer to confirm the delivery date and address using a form"). The form appears in the chat under the agent's message, and the person's answers come back to the agent as their reply. Off by default.
One-time form submissions — when enabled, each form can be answered only once. When off, the person can submit the same form again.
Step error message — optional text sent to the end user if a step that replies in this conversation ends with an error. Leave blank to use the default: There was an error handling your message.
To keep a step from replying to the person in the chat — for example a step that quietly looks something up or updates fields — remove the conversation property from that step's Output properties in its AI Instructions. Steps that should greet, ask, or answer keep the conversation in their Output properties.
If a custom tool should own the back-and-forth — collect a list of answers, walk a fixed script, or wait for replies — give that tool a Conversation input. See How to build a tool that uses a conversation.
If a step that lists the conversation under Output properties ends with an error, Thunk sends that step error message so the person in the chat knows something went wrong. Steps without the conversation in Output properties do not send it.
Add structured inputs (optional)
A chat-based workflow can collect more than just messages. If you add other input properties to the workflow — text fields, numbers, dates, files, or any other type — those inputs appear as a start form when an end user begins a new conversation.
For example, if your workflow needs a customer ID and a priority level before the conversation begins, add those as input properties alongside the conversation property. When the end user clicks New chat, they first fill in those fields, then the chat begins with that context already available to the agent.
This is useful when the workflow needs structured data up front rather than having the agent ask for it in the conversation.
Open the Chat UI
Once the workflow has a conversation input, you can open the hosted chat page two ways:
From the left navigation, choose Run → End User Chat UI.
Or go to Run → Inbound Requests → Chat UI and click Chat UI.
Either one opens the chat app in a new browser tab. If the Chat UI button is disabled, the workflow does not yet have a conversation input property — add one and it turns on.
Share it with end users
The Chat UI opens at its own web address. Share that link with the people who should chat with your thunk. They sign in to Thunk.AI to use it, and only people you have added to the thunk can chat. Each person's conversations stay separate, and every conversation becomes its own work item your workflow runs.
Give people access
Having the link is not enough on its own: someone who is not on the thunk cannot chat with it. To let people chat without giving them access to anything else, add them to the thunk with the End User role:
Open your thunk and click Share in the header.
Enter one or more email addresses.
Choose End User from the role dropdown.
Click Invite.
You can also add them from Admin → Users and Roles, in the End Users section. The thunk's owner, admins, and human agents can use the Chat UI too.
End Users can only interact with the thunk through its Chat UI — they cannot see the work items, plan, settings, or other users' data. For more on how roles control access, see Users and Access Controls.
What end users see
In the Chat UI, a person can:
Start a conversation with New chat. If the workflow has structured inputs (fields besides the conversation), a start form appears first to collect them; otherwise the person starts typing right away.
Send messages and read the agent's replies in the thread. A typing indicator shows while the agent is working.
Attach files to a message (when User file attachments is enabled on the conversation property).
Fill in and submit a form the agent sends (when Form responses is enabled). Their answers appear in the thread as their message, and the agent continues from them. They can still type a reply instead. A file question in a form takes a link to the file, not an upload.
If a step that was talking to them ends with an error, they see the default error message — or the custom Step error message you set.
Switch between their earlier conversations from the sidebar. The list follows the person, not the browser: they see the same conversations on any device they sign in from. Conversations started before this was introduced still appear only in the browser they were started in.
Download the conversation as a PDF to keep a record.
End the conversation when they are done. Ending is final — it stops the agent and completes the work item.
The thunk's owner, admins, and participants also see a View work item link on a conversation, which opens the underlying work item so they can follow what the workflow did.
Chat UI vs. the REST API
Goal | Use |
Let people chat with your thunk on a ready-made page | This article (hosted Chat UI) |
Embed chat in your own website, app, or portal | |
Let a custom tool own the back-and-forth on that conversation |