Session spend limits

A spend limit stops a session's model work once its reported cost reaches a USD amount you choose, and lets the owner raise it to continue.

Where limits are set

Workspace default

Under Settings › Sandbox, the Session Cost section has one field, Cost limit (USD). The description reads: "Stops additional model work after reported session cost reaches the limit. Leave the limit blank for unlimited sessions. Unreported model cost cannot be limited."

• Blank means no limit. The placeholder reads "No limit".
• The value must be a positive amount. Zero and negative values are rejected with "Session cost limit must be a positive USD amount."

Repository and environment overrides

The same field appears in a repository's and an environment's sandbox settings. There the placeholder reads "Inherit", and leaving it blank inherits the broader setting. Enter a value to override it for sessions on that repository or environment. See Sandbox settings for how the levels resolve.

One session

The session's right sidebar has a Budget section. It reads "No session cost limit" until a cost is reported or a limit is set, then "Session cost: $X" or "Session cost: $X of $Y limit".

To change the limit for this session only:

1. Click Edit limit.
2. Enter a value under "USD limit for this session" and click Save, or click No limit to remove it.

The note under the field reads "Applies only to this session." A non-positive value is refused with "Enter a positive USD amount". The API equivalent is PATCH /sessions/:id/budget with maxCostUsd set to a positive number or null.

Who can change it

• Workspace, repository, and environment limits are edited in Settings by whoever can manage sandbox settings.
• The per-session limit can be changed only by the session's owner, and only when that owner also has session lifecycle permission. Other participants see the Budget section but not Edit limit.

How cost is measured

The harness running in the sandbox reports the cumulative cost of the current turn on every step and again when the turn ends. The session total grows only by the amount a report exceeds the highest one already recorded, so a resent report adds nothing and a dropped one is repaired by the next.

The Budget section notes that "Costs and limits reflect reported model usage only." Model usage that the harness does not report cannot be limited.

What happens when the limit is reached

As soon as a cost report brings the session total to the limit or above:

1. The session is marked budget-exhausted.
2. A warning is written to the timeline with the text Session cost limit reached: $X of $Y. Execution stopped. (or Work paused. when nothing was running).
3. The running turn is stopped.
4. Queued prompts stay queued and are not dispatched.
5. New prompts are refused. The composer is blocked with "Session cost limit reached at $X of $Y. Raise or remove the limit to continue." for the owner, and "The session owner must raise or remove the limit to continue." for everyone else. Feedback queued by PR Feedback Autofix is rejected for the same reason.

The stop is a normal execution stop, so the workspace is left as it was at that moment and follow-ups can pick up from there.

Resuming

Raise the limit above the current total, or remove it, from the Budget section. Queued prompts dispatch again immediately, and a new follow-up runs as usual. If you lower a limit below the amount already spent, the session stops in the same way at once.

Troubleshooting

Next steps

• Sandbox settings
• Analytics
• Session lifecycle and statuses