[Bug] Anthropic API Error: Tool result without corresponding tool use block
Open 💬 0 comments Opened Jun 9, 2026 by sparkwell-dev
Bug Description
API Error: 400 messages.5.content.0: unexpected tool_use_id found in advisor_tool_result blocks:
srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each advisor_tool_result block must have a corresponding server_tool_use block
before it.
Cant get out of this loop. I've wasted hundreds of thousands of credits restarting new chat windows. This needs to be fixed.
Environment Info
- Platform: darwin
- Terminal: cursor
- Version: 2.1.169
- Feedback ID: 6ba1f056-4918-4d45-828e-2f8196e1ecc3
Errors
[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssBCX5HbqqRHpMRsTBP\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:45:16.805Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssBEmGARJdnsETQxcp1\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:45:17.374Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssBsaL1zRWxdKatmv84\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:45:25.991Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssCwPoF4KXUNirPLC1T\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:45:40.393Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssFLHWef7mjsGGqcBTy\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:46:13.136Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbssqeByb6BYWyPGogXwE\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:53:58.287Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.0: unexpected `tool_use_id` found in `advisor_tool_result` blocks: srvtoolu_01V69zF5xm68rk7JaA1SWaFc. Each `advisor_tool_result` block must have a corresponding `server_tool_use` block before it.\"},\"request_id\":\"req_011CbsswMkRfW68Tk7v6qbMS\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68056)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-09T14:55:15.831Z"}]