GPT-5.3 Codex Spark starts running the plan while still being in Plan Mode
Steps to Reproduce
Start a plan, do a few refinements and when close to filling the context window, request a small refinement on the plan and answer Yes if it asks about running the plan as well.
Expected Behavior
Either not run the plan, or switch modes to Agent.
This is a known issue. Plan mode not being respected is something the team is tracking. It has been reported across different models, but GPT-5.3 Codex Spark seems especially prone to it.
One detail from your report. You mentioned answering “Yes” when the model asked about running the plan. That likely triggered execution even though you were still in Plan mode. For now, it is worth watching for those confirmation prompts.
A workaround that has helped other users is to create a .cursor/rules/plan-safety.mdc file with:
---
description: Plan mode safety
alwaysApply: true
---
CRITICAL: In PLAN mode, NEVER edit files or run commands. Only describe the plan. Wait for explicit user approval before any implementation.
This does not fix the root cause, but it does reduce how often the model jumps ahead.
Your report, with the request ID, helps with prioritization. Let me know if the workaround helps.
