Cursor via ACP in Intellij, plan mode does not create the plan

[Lucas_Rezende_1994 (Lucas Otávio Pereira Rezende)]

Where does the bug appear (feature/product)?

Somewhere else…

Describe the Bug

I’m using Cursor via ACP in Intellij and I tried to create a plan (using Codex 5.3 as model). I used a skill with slash (/brainstorming, did not see anything about the model use that skill) and then a message comes saying Create plan but the plan does not materialize

Only after I asked to create a .plan.md file in a specific directory the plan was made

Steps to Reproduce

1. Install Cursor via ACP in Intellij
2. Select Codex 5.3 as model
3. Select Plan mode
4. Try to use a skill and create a plan
5. See that the plan was not created at the end

Expected Behavior

At the end a new file needs to be created and open in editor

Operating System

MacOS

Version Information

CLI Version 2026.01.17-d239e66
IntelliJ IDEA 2025.3.3
Build #IU-253.31033.145, built on February 20, 2026
Source revision: 212d61deaf3a8
Runtime version: 21.0.10+7-b1163.108 aarch64 (JCEF 137.0.17)
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.lwawt.macosx.LWCToolkit
macOS 26.2
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 4096M
Cores: 12
Metal Rendering is ON
Registry:
ide.experimental.ui=true
terminal.new.ui=true
llm.chat.agent.codex.install.codex.version=0.106.0
maven.packagesearch.enabled=false
llm.chat.agent.codex.install.acp.server.version=0.0.27
llm.selector.config.refresh.interval=10
llm.rules.refresh.interval=10
Non-Bundled Plugins:
paviko (26.2.27)
AntSupport (253.28294.251)
com.intellij.ml.llm (253.31033.145)
PlantUML integration (7.13.0-IJ2023.2)
org.asciidoctor.intellij.asciidoc (0.45.3)
com.github.copilot (1.5.66-243)
Kotlin: 253.31033.145-IJ

For AI issues: which model did you use?

Codex 5.3

Does this stop you from using Cursor

No - Cursor works, but with this issue

[deanrie]

Hey, thanks for the report. ACP + JetBrains is very new, so this kind of feedback is really helpful.

A couple of things to check and try:

1. Your CLI version is 2026.01.17, so it might be outdated. Try updating with agent update (or reinstalling from the docs) and see if the behavior changes.

2. Can you share the Request ID from the session where the plan didn’t show up? That would help us trace what happened on the backend.

3. ACP has a cursor/create_plan extension method that the client (the JetBrains AI plugin) needs to handle. If the JetBrains side doesn’t support it yet, the plan creation request can get dropped, which matches what you’re seeing. The team is tracking this as ACP matures.

For now, your workaround of explicitly asking the model to create a .plan.md file is solid. You can also add a Cursor rule to make this automatic:

---
description: Plan mode in ACP
alwaysApply: true
---
When in plan mode, always write the plan to a .plan.md file in the project root.

I flagged this with the team. Let me know if updating the CLI changes anything.