The Model Builder builds a semantic model from one approved design. You meet it in a chat with the Warehouse Builder: it proposes the design, works through it in rounds, and reports back until the model is ready. Model Builder sessions and Model Builder cards go deeper on the session itself.
Start a build
Open a chat with the Warehouse Builder Mind.
Type /star-schema in the message box. The command reads "Use the Star schema skill: design and build a semantic model", and it joins your message as a Star schema pill.
Send the message. The build loads the skill, and the transcript shows a chip reading Using: Star schema v1, with the tooltip "A DataMind playbook shipped with this platform version".
Answer the questions the builder asks in the chat, then review the design it proposes.
Approve the design
The design arrives as a card headed Semantic model design. It lays out the fact and the dimensions it will build, the objects the model will read, and the choices to make: the owner role, the data mode (Tokenized (recommended) or Clear values), and the history depth. For every section of the card and how to set the choices, see The semantic model design card.
Set the choices while the card waits for your decision.
Approve with the button built from your choices, for example Approve · owner role · data mode · history option. To send the design back instead, choose Reject with a note.
Once you decide, the card locks. The build records the decision as: Design approved (session <id>): owner role <role>, data mode <mode>, history "<option>".
Follow the rounds
The builder works through the design in rounds and reports each round back into your chat as a card. Between your decisions it works on its own.
A strip above the message box keeps the session in view: Model Builder · model · round n of m, with a Needs you: n badge when something waits for you. Select the strip to open the session card.
If the build wants to change a table that existed before the design, it asks first, under The Model Builder needs a change on a shared table. The options are I will make it in the Warehouse Builder chat, Continue without it, or Answer in your own words; the hint reads "This table existed before this design, so the Model Builder changes it only with your word."
Messages you send while a round runs wait for it. The composer shows "Your message is delivered right after the Model Builder's round", and attachments are refused with "Attachments cannot be queued while the Model Builder works. Send the text now and the image after its round, or wait for the round to end." If someone else already has a message queued, the refusal reads "name already queued a message for after the Model Builder's round. Wait for the round to end, then send." The queued message itself and its Remove action are described on Model AI.
A session allows 8 rounds, a 12-hour deadline and a 30M token budget. When it stops at its round limit, the person who started it can add 2 more rounds once, with Continue with 2 more rounds; the maximum is 10.
Grant access to the objects
Before the model is created, the build checks that its owner role can read every object the model needs. When something is missing for a business role, the chat shows a card titled Grant role access.
Choose Open permissions on an object that is not granted, add the role under Permission Groups in the Warehouse popup, and save it.
Choose I've granted them, check again. It sends "I granted the access. Check again." into the chat and runs the check again. The card counts the progress as "n of m granted", and each object reads Granted, Not granted, Columns missing, Not deployed or Not found.
Repeat until everything is granted. The admin role reaches every object, so its card finishes straight away.
The build creates the model empty in the requester's personal workspace: "Created empty in the requester's personal workspace; move it later with Move."
On the created card, Send the brief to Model AI sends the build brief into the model's Model AI chat and opens the model; Open Model AI chat opens the model without sending anything. When the Model Builder sends the brief itself, the card says "The Model Builder sends the brief and builds this model with its Model AI." and the send button is hidden.
The build records the creation as: Created the empty semantic model "<name>" in <requester>'s personal workspace (owner role <role>, data mode <mode>).
Note
The model is created empty. Its contents arrive in rounds, built through the model's Model AI from the build brief. The model itself is described in Semantic models and BI tables.
When the build ends
The done card reports the outcome, with its scorecard and what still wants attention. Its headline reads Your semantic model is ready, or Ready, with charts that failed, Needs your attention, Stopped or Failed when the build ended differently. Model Builder cards shows how to read it.
A session that ends on its own says why in plain words:
Used all 8 rounds. Continue with 2 more rounds, or open the Model AI chat to finish by hand.
Reached its 12-hour limit. Start a new session from this chat, or finish in the Model AI chat.
Used its 30M token budget. Start a new session from this chat.
The build runs in a chat with the Warehouse Builder Mind, which is visible to the admin role only. See Warehouse Builder and Lake Builder.
While you view the platform as another user, a session stays readable, but you cannot act on it: "Model Builder actions are not available while you are impersonating another user."
Questions, answered
How do I start a build?
Open a chat with the Warehouse Builder Mind and type /star-schema. The build loads the skill, asks its questions and proposes a design; approve that design to set the build going. The steps are above, and the chat itself is described on Warehouse Builder and Lake Builder.
Does approving the design build the model straight away?
No. Approval starts a build that works in rounds. The model is created empty in the requester's personal workspace, and the model's Model AI builds it from the build brief. The done card tells you when the build is finished.
Who can decide the changes the build asks for?
The person who started the build. When someone else tries to decide, the message reads: "Only name, who started this Model Builder, can decide its changes." Others can still read the session.
Can I run a second build on the same model?
No. One build works on a model at a time. While a session is open, another one is refused with "A Model Builder is still working on this model."
Can I follow the build from the model instead of the chat?
Yes. While the build runs, the model's Model AI panel shows a banner above the chat, for example Model Builder is working · round n of m · started by name, with Stop where you can stop it. See Model AI.
What ends a build?
A session ends when it uses its 8 rounds, reaches its 12-hour limit or uses its 30M token budget; a failure can end it too. The card says why in plain words. For every ending and how to continue, see Model Builder sessions.