Where does the bug appear (feature/product)? Cursor IDE Describe the Bug When the Cursor main agent wants to start a Subagent it is stuck at “New Subagent - Starting up” without continuing. This feature breaks workflows that requires or triggers Subagents. Steps to Reproduce Ask the Agent to sta…

Hey @mohitjain thanks for answer, no it does not show any updates or results. I clearly noticed it because I was working on developing subagents orchestrator skills right before I updated Cursor. After the update it stucks, no files update, no tokens uses and etc. Version: 3.1.17 VSCode Version: …

Thanks for the update. Two new reproductions today with an identical fingerprint: Dispatch succeeds end-to-end: Cursor returns an agentId, and the subagent’s result persists as agentKv:blob:<hash>. The child composerData:<agentId> row never gets written, so subagentComposerIds on the parent s…

same issue here, it looks stuck, but it’s actually running, I can see diff keeps growing. There is no progress to know what’s each agent is doing. [Screenshot 2026-04-21 at 10.44.40 PM]

Thanks for the updates, everyone. @vladbond – really appreciate the continued deep analysis. Your finding that the conversation data isn’t persisted (while the result blob does land) is a good one. You’re right that this goes beyond a pure rendering issue. I’ve passed this along. @Duc_Trung_Mai –…

one of my solution is to tell agent “do not spawn new agent, I don’ t need parallel processing”, doing “single threaded” task is faster because I can see performance of multi agents are pretty bad, slower than I use 1 agent, and with 1 agent I can see its progress

[image] Sergei Kundriukov: Version: 3.1.17 VSCode Version: 1.105.1 Commit: fce1e9ab7844f9ea35793da01e634aa7e50bce90 Date: 2026-04-19T19:33:58.189Z Layout: editor Build Type: Stable Release Track: Default Electron: 39.8.1 Chromium: 142.0.7444.265 Node.js: 22.22.1 V8: 14.2.231.22-electro…

Where does the bug appear (feature/product)? Cursor IDE Describe the Bug I am using a SKILL which describes the coding process. This SKILL must have spawn specific subagents described in dedicated files for subtasks e.g. coding, testing, reviewing. After I updated Cursor to v3.0+ it stopped working…

@Colin could you reopen the thread I linked above? @mohitjain has asked me to open it and it is a complete different issue

Ah sorry about that @Sergei_Kundriukov . Reopening!

3.1.17 There’s still a problem. It’s so uncomfortable. I don’t know what this subagent is doing. It’s not moving at all, which seriously affects the user experience, [image]

Sub Agents wont run and are stuck at "New Subagent - Starting up"

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Sergei_Kundriukov (Sergei Kundriukov) April 22, 2026, 3:25pm 24

Opened it here Spawning Subagents do nothing in some circumstanses

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Sub Agents wont run and are stuck at "New Subagent - Starting up"

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