Getting “something went wrong” when using the new “grind” mode agents, I can’t access the agent, and what’s worse, I can’t create new agents from the web!
The message is:
Something went wrong
An error occurred while loading the agents page. Please try again.
go back to https://cursor.com/agents and see “Something went wrong
An error occurred while loading the agents page. Please try again.”
click search, see the agent there, it’s running, click it, get the same “Something went wrong
An error occurred while loading the agents page. Please try again.”
NOTE: it happens to me in Chrome, but seems to work in Safari…
It looks like a serialization bug on the Agents page, specifically the ToolResult.tool_call toJson error that @Subsolum saw in the console. The fact that it happens with GPT 5.4 but not with 5.3 Codex is a helpful clue.
I’m passing this to the team. The request ID and the console error details should help them track it down.
In the meantime, here are a couple workarounds:
Try a different model. Based on @Subsolum’s tests, 5.3 Codex works.
Like you mentioned, Safari handles this error differently, so it might work as a temporary workaround.
Encountered this today as well. I’m using Windows 11, Google Chrome and Composer 1.5 as my model. Even if I create new agents, I keep on encountering this error. Encountered it on two projects already.
98690-3a791d0eb92baf…K3mDyBoy6AqRdPmFt:1 Error: cannot encode field aiserver.v1.ConversationMessage.ToolResult.result to JSON: E(…).toJson is not a function
at Object.writeMessage (77120-739a1eea1a691e…oy6AqRdPmFt:1:26407)
at ConversationMessage_ToolResult.toJson (77120-739a1eea1a691e…Boy6AqRdPmFt:1:4306)
at ConversationMessage_ToolResult.toJSON (77120-739a1eea1a691e…Boy6AqRdPmFt:1:4457)
at JSON.stringify ()
at k (85773-5d3a32009eb335…oy6AqRdPmFt:1:74866)
at F (85773-5d3a32009eb335…oy6AqRdPmFt:1:78334)
at d (66446-9f76fac5a6d933…y6AqRdPmFt:1:118732)
at 66446-9f76fac5a6d933…oy6AqRdPmFt:1:43018
at o1 (24795f5d-69def8a2104…oy6AqRdPmFt:1:88958)
at uE (24795f5d-69def8a2104…y6AqRdPmFt:1:104850)
error-41ea2ca22c793b…K3mDyBoy6AqRdPmFt:1 [AgentsError] Error: cannot encode field aiserver.v1.ConversationMessage.ToolResult.result to JSON: E(…).toJson is not a function
at Object.writeMessage (77120-739a1eea1a691e…oy6AqRdPmFt:1:26407)
at ConversationMessage_ToolResult.toJson (77120-739a1eea1a691e…Boy6AqRdPmFt:1:4306)
at ConversationMessage_ToolResult.toJSON (77120-739a1eea1a691e…Boy6AqRdPmFt:1:4457)
at JSON.stringify ()
at k (85773-5d3a32009eb335…oy6AqRdPmFt:1:74866)
at F (85773-5d3a32009eb335…oy6AqRdPmFt:1:78334)
at d (66446-9f76fac5a6d933…y6AqRdPmFt:1:118732)
at 66446-9f76fac5a6d933…oy6AqRdPmFt:1:43018
at o1 (24795f5d-69def8a2104…oy6AqRdPmFt:1:88958)
at uE (24795f5d-69def8a2104…y6AqRdPmFt:1:104850)
Steps to Reproduce
Run any cloud agent. It’s happened on multiple agents for me and I can’t see any consistent theme
Expected Behavior
Cloud agent to run normally and I can see its progress
Thanks for the quick reply, and glad to hear it’s in the works. Any ETA?
By the way, switching to safari worked initially, I asked it to handle some merge conflicts and now I can’t access it also on safari. I can’t switch models per se, and there is 10 hours of work on that agent session, I hope it committed and pushed everything… do I need to create a new agent on that branch?
After 30 minutes running on a task, the frontend shows: “Something went wrong
An error occurred while loading the agents page. Please try again.”
Reloading the page shows the same error. The Chrome console shows:
[AgentsError] Error: cannot encode field aiserver.v1.ConversationMessage.ToolResult.tool_call to JSON: E(…).toJson is not a function
Steps to Reproduce
For now this has only happened on a specific task we have. The task runs correctly for ~30 minutes and then this happens. We’ve tried with the same task two times and have had the same result.
