Credits and usage

Credits measure AI work in Mythos. Builds and edits use usage-based pricing within the credit limit you choose. Plan turns and template remixes have the fixed prices shown below. A prompt length or token count alone does not determine the price of a completed Build.

Free accounts receive 5 credits once after account confirmation. Pro and Business subscriptions include monthly credits; their billing owner can also buy top-ups or explicitly enable automatic top-up. Open Billing to see your available balance, expiry dates, frozen credits and history. In a shared workspace, AI work uses the workspace billing owner’s balance.

What actions cost

Build and edit usage is calculated from AI API tokens and image generation under the accepted tariff. Compilation, typechecks and browser verification add no separate credit charge. The final charge is rounded up once to the next 0.1 credit. A downloadable file produced by the same Build has no separate artifact fee. The accepted price is pinned to that Build; a later price change does not reprice work already accepted. Older runs retain their original charging rules.

Open More actions (…) on the assistant message to review its credit usage and measured duration when available. The duration is shown for reference; charges follow the usage rules above.

Choose a Build limit

Open the Build section in account settings to change your default, or set an override in Project settings. Free accounts start at 5 credits and paid plans at 10 credits. Saved account preferences replace these starting defaults; a project override takes precedence. Without an override, a shared project uses the default of the person starting the Build.

You can save a limit from 0.5 to 100 credits in steps of 0.1, subject to workspace permissions. Each new Build reserves up to that limit or the available balance, whichever is lower. Changing settings does not change a Build that has already been accepted.

The limit is a maximum, not a fixed charge. Mythos shows usage as work progresses and returns the unused reserve when the Build settles. A short edit can use much less than its limit.

Mythos aims to finish and verify a coherent result within the remaining budget, then reports any work left for a later request. If a required next AI step cannot safely fit, the Build can pause with its working copy saved. Review the budget card and explicitly raise the limit to continue the same Build, or stop it. Resuming does not add a second minimum charge. A paused working copy is not a newly delivered version; the current Preview remains available.

When credits are kept or returned

• A Plan turn costs 1 credit only after Mythos saves a response, questions, or a plan draft.
• A delivered Build or edit settles its measured usage within the accepted limit.
• A platform failure before delivery normally returns the reserved credits.
• Choosing Stop after AI work has begun charges the work already consumed, subject to the minimum charge, and returns the unused reserve. Stopping before any paid work starts is free.
• If delivery or an external action may already have started, settlement can remain pending while Mythos reconciles the outcome.

The balance can take a moment to reflect a final refund or charge. If it remains unsettled or looks wrong, do not repeat the action only to change billing; contact support with the project and action.

Actions that do not use credits

These actions do not start an AI run:

• Editing and saving the Plan draft yourself.
• Approving or cancelling a Plan session. The Build started after approval has its own normal price.
• Editing a project file directly in the workspace editor, when your plan and permissions allow it.
• Viewing an earlier version or reverting to it.
• Publishing or republishing an already delivered project.

External services you connect may have their own billing. Mythos credits do not pay a domain registrar or another provider bill.

Plans and access

Subscription features depend on the workspace’s paid plan, not on having ten credits in its balance. All plans allow unlimited sites, code viewing, Preview and publishing to a Mythos URL. AI work still uses the charging rules above.

• Free includes the five one-time signup credits, with no daily or monthly credit grant.
• Pro adds GitHub connections and two-way sync, ZIP download, direct code editing, custom domains, team invitations, roles and member credit limits.
• Business adds project Room conversations, eligible direct-message sending and Restricted access for team projects. Personal projects can remain private on every plan.

GitHub connections, ZIP downloads and direct code editing require an active Pro or Business subscription and the appropriate project permissions. A credit balance alone does not unlock them. See the current plans and pricing before choosing a workflow.

Existing project data, access restrictions and authorized message history are preserved when a paid plan ends. New paid actions require the relevant active plan. In a shared workspace, contact the billing owner to manage its plan.

Monthly credit options

Subscriptions renew monthly until cancelled. Annual billing is not offered.

Prices are in USD. Review the final amount and any applicable charges before confirming. Cancel renewal in Manage billing to keep paid access until the current paid period ends. Plan changes show their charge or next-period effective date for confirmation.

Expiry, rollover and frozen credits

For new offers under billing terms edition 2026-09-17, each monthly credit allocation expires 60 days after it is issued. Unused credits can roll into the next monthly period without a separate rollover-amount cap, but their original expiry date stays the same.

After the paid period ends and the workspace returns to Free, its unexpired monthly credits are frozen. Resubscribing to Pro or Business makes those credits available again only if they have not expired. Time spent on Free does not extend their expiry.

Top-ups expire 12 calendar months after purchase. Purchased top-ups remain usable on Free until their own expiry. Previously issued non-expiring credits retain their original terms; this edition does not retroactively expire or freeze them.

Buy once

Only the authorized billing owner of a workspace with current Pro or Business access can buy new top-ups. Cancelling renewal does not remove that option while the paid period is still active. Free and signed-out users must first subscribe; a top-up is not a separate plan.

In Billing → Add credits → Buy once, choose 50, 100, 150, 200, 250, 300, 400, 500, 1,000, 2,000 or 3,000 credits. Pricing depends on the current paid plan: 100 credits cost USD 30 on Pro or USD 60 on Business. These quantities use the same per-credit price: USD 0.30 on Pro or USD 0.60 on Business. The final price is presented before payment.

Automatic top-up

Automatic top-up is optional. In Billing → Add credits → Auto top-up, choose the quantity, threshold and monthly limit, review the per-purchase price, then explicitly enable it.

• Automatic purchases cost USD 0.30 per Pro credit or USD 0.60 per Business credit. For example, 100 credits cost USD 30 or USD 60 respectively, matching Buy once.
• A purchase can start when the available balance reaches or falls below the selected threshold: 25, 50 or 100 credits.
• The monthly cap is 100, 200, 400, 1,000 or 2,000 automatic top-up credits in a UTC calendar month, or an explicit No limit choice. A numeric cap must cover at least one selected top-up; a purchase that would exceed it does not start. Billing shows the corresponding spending amount.
• Selecting options alone does not authorize charges. Setting up a payment method leaves automatic top-up disabled until you explicitly enable it.
• Disable stops new automatic purchases; a payment already submitted may still complete. A failed payment or required authentication pauses automatic purchases. A changed plan or agreed price needs fresh consent.

Automatic top-up is available only during current Pro or Business access. Its purchased credits have the same 12-calendar-month expiry and post-subscription availability as Buy once.

Promotions and refunds

An accepted promotion changes the price, not the confirmed credit quantity. Monetary refunds use the amount actually paid after the discount. Fully discounted promotional credits have no cash amount to refund. A partial refund reverses the corresponding proportion of the purchase’s credits, rounded up to whole credits; a full refund of the paid amount reverses all of that purchase’s credits. For example, refunding USD 10 of a 100-credit purchase discounted to USD 20 reverses 50 credits.

The Terms of Service describe refund requests and mandatory consumer rights. Earlier purchases retain the terms and rights that applied when made.

If the balance is too low

A new Build uses your saved limit or the available balance, whichever is lower. It cannot start if the available balance is below the 0.5-credit minimum. Plan and remix require their fixed price. A billing owner with paid access can buy a top-up in Billing, or wait for the next monthly allocation. On Free, choose a monthly plan to obtain a new paid allocation. In a shared workspace, ask its billing owner to review the balance. If the displayed balance or a refund looks wrong, contact Mythos support with the project and action that produced the mismatch.

Keep usage predictable

• Use Plan mode when a first request still has important open decisions.
• Set a limit you are comfortable spending and review usage before increasing it.
• Ask for one coherent outcome per edit, then inspect the result before sending another.
• Use the workspace editor for a small change you already know how to make directly.
• Revert a poor direction before asking for more work on top of it.

Continue with Building and editing to see how an AI action moves from a prompt to a delivered result.