Build mode vs Plan mode. In Build mode Mythos builds directly from your prompt. In Plan mode it questions → drafts → waits for approval, then starts the normal Build. Each accepted AI turn in Plan mode costs 1 credit; the Build after approval is charged separately.
Why use it
- Clarify the brief first. Focused questions surface missing requirements before a build spends time implementing the wrong thing.
- Keep one durable plan. Mythos saves each completed planning response and produces a plan draft tied to this project.
- Stay in control. You can edit the draft yourself and choose when to approve it. No code is built before approval.
How it works
1
Turn on Plan mode and send your prompt
Toggle Plan by the composer, then describe what you want. Mythos starts the planning session without starting a Build.
2
Answer focused questions
Mythos may ask a few short questions about the product, content, interactions, data, or constraints. Reply in the planning conversation; it may ask a follow-up or move straight to a draft when the brief is clear.
3
Review and edit the plan draft
Mythos saves a concrete plan draft in the session. Edit the Markdown directly if needed. Saving your own draft changes is local and does not make an AI call or spend another credit.
4
Approve the plan
Approve only when the scope is right. Approval binds that exact plan to the next Build; cancelling or continuing the planning conversation does not start code generation.
5
Build
Approval starts the normal Build from the approved plan. A new-project Build costs 3 credits, separately from the Plan turns that produced the draft.
What the questions cover
Questions are selected for your brief, so they vary from project to project. They can cover:- Purpose and audience — who the app is for and what outcome it should produce.
- Pages and content — what the project should show and how information should be organized.
- Interactions — forms, navigation, user actions, and other behavior that matters.
- Data and constraints — whether the project needs connected data, authentication, uploads, or other boundaries the Build must respect.
Example prompt
A Plan-mode prompt is just a normal first prompt — turn Plan on, then describe the project:Credits and failures
Each accepted AI turn reserves 1 credit. The credit is spent only after Mythos saves a durable message, questions, or plan draft. If that turn fails before its response is saved, the reservation is refunded automatically. Editing or saving the draft yourself, approving it, or cancelling the session does not spend another Plan credit. The Build after approval uses the normal Build price.Limitations & good to know
- Plan mode is for starting a project. To change an existing project, prompt it in Build mode.
- A planning response can be a message, a short set of questions, or the durable plan draft. Continue the same session until the draft is ready to approve.
- Approval starts a normal Build; it is not a free preview or a separate generation path.
FAQ
Does Plan mode cost credits?
Does Plan mode cost credits?
Yes. Each accepted AI turn costs 1 credit after its response is saved. A failed turn is refunded automatically, and the Build after approval is charged separately.
Can I edit the plan before building?
Can I edit the plan before building?
Yes. Edit and save the Markdown draft locally, then approve the exact version you want Mythos to build. Local draft edits do not make an AI call or spend a credit.
What if the draft is not ready?
What if the draft is not ready?
Keep planning in the same conversation or edit the draft directly. No Build starts until you approve.
What happens after approval?
What happens after approval?
Mythos starts the normal Build from the approved plan. For a new project, that Build costs 3 credits.
Related
- Quick start — the full first-build flow.
- Writing good prompts — a sharper prompt makes planning more direct.
- Credits & pricing — Plan-turn and Build costs.