# \# Bug: GLM-5 (Modal Research) — Agent tool calls return empty (no output, no error) **URL:** \ **Category:** Bug Reports\ **Tags:** byok\ **Created:** [April 8, 2026, 11:48pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099 "2026-04-08T23:48:48Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Ryan\_Guadalupe](https://avatars.discourse-cdn.com/v4/letter/r/41988e/32.png) [@Ryan\_Guadalupe](https://forum.cursor.com/u/Ryan_Guadalupe)\ **Post date:** [April 8, 2026, 11:48pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/1 "2026-04-08T23:48:48Z")
### **Describe the Bug** **Environment** - Cursor version: 3.0.13 (commit/distro: d5c0e77a0214208f36b56d42e8e787de88d02ea4) - OS: Windows 10 (22H2, build 19045) - Workspace: E:\PROYECTOGAMBUSINAS (local drive, trusted folder) - Model: GLM-5 via Modal Research (OpenAI-compatible endpoint) - Other models in same workspace: Claude, GPT-4o — all work fine **Description** When using GLM-5 (Modal Research) as the Agent model, all tool calls (Read, Shell, Glob) return completely empty — no output, no error, no status code. The tools appear to execute but produce zero response. Other Cursor-native models in the exact same workspace and session work correctly, confirming this is not a workspace trust, sandbox, or filesystem issue. **Steps to Reproduce** 1. Open Cursor 3.0.13 on Windows 10 (22H2, build 19045) 2. In Settings → Models, configure GLM-5 via Modal Research (OpenAI-compatible endpoint, API key per Modal) 3. Open workspace E:\PROYECTOGAMBUSINAS (trusted folder) 4. In Agent, request e.g.: “Read Las-Gambusinas\services\configuracionService.js” or “Run dir on the project root” 5. Observe that Read / Glob / Shell return no output and no error message 6. Switch to a Cursor-native model (e.g. Claude or GPT-4o) and repeat the same request: tools return results correctly **Expected Behavior** Read, Glob and Shell should return file contents, directory listings, or terminal output — same as with Cursor-native models. **Actual Behavior** All three tools (Read, Shell, Glob) return empty with no error: - **Read** : no file content shown - **Glob** : no file list returned - **Shell** : no command output, no exit code No error message is displayed — the failure is completely silent. **Likely Cause** GLM-5 / Modal Research endpoint does not correctly format `tool_calls` responses in the OpenAI-compatible schema that Cursor expects for agent tools. The model may be: - Omitting `tool_calls` from its response entirely - Returning malformed JSON in tool call arguments - Using MTP/speculative decoding that corrupts tool call JSON (this has been reported by other users in the community) **Workaround** - Use a Cursor-native model (Claude, GPT-4o, etc.) for Agent tasks - GLM-5 can still be used for chat without tool requirements **Related** - Community reports indicate disabling MTP (`--speculative-config.method mtp`) on self-hosted vLLM can fix similar tool calling corruption - Cursor ≥ 2.0.74 includes patches for external model tool calling — issue persists even on latest version **Request** Can the Cursor team investigate how the Agent tool call protocol handles OpenAI-compatible endpoints that may not fully conform to the expected `tool_calls` schema? A more descriptive error or fallback would help diagnose these issues faster. **Operating System** Windows 10/11 **Version Information** Cursor: 3.0.13 (from package.json at E:\Program Files\cursor\resources\app\package.json). Commit/distro: d5c0e77a0214208f36b56d42e8e787de88d02ea4. **For AI issues: which model did you use?** GLM-5 through Modal Research (OpenAI-compatible API / base URL override in Cursor). **For AI issues: add Request ID with privacy disabled** 4a11cfeb-8c69-41bb-89e4-5a01e234a3ec **Does this stop you from using Cursor?** Yes — Cursor is unusable ---
**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\ **Post date:** [April 8, 2026, 11:49pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/3 "2026-04-08T23:49:00Z")
Unlisted on April 8, 2026, 11:49pm UTC ---
**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\ **Post date:** [April 8, 2026, 11:49pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/4 "2026-04-08T23:49:05Z")
Hi, Thanks for posting on the Cursor forum! To help ensure most of our users can participate in discussions, this forum is currently English only. If you’d like, you can edit your post to translate it into English. Once it meets our guidelines, it will be automatically relisted. Specifically, the “Steps to Reproduce,” “Expected Behavior,” and “Version Information” sections contain Spanish text — translating those into English will bring the post in line with our guidelines. Thanks for understanding! _Note: This is an automated detection system and sometimes makes mistakes. If your post is already in English, feel free to ignore this message, or just make a small edit and it will be reviewed again._ ---
**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\ **Post date:** [April 9, 2026, 9:24pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/6 "2026-04-09T21:24:20Z")
Listed on April 9, 2026, 9:24pm UTC ---
**Author:** ![JonasH](https://avatars.discourse-cdn.com/v4/letter/j/2acd7d/32.png) [@JonasH](https://forum.cursor.com/u/JonasH)\ **Post date:** [April 10, 2026, 10:27pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/8 "2026-04-10T22:27:51Z")
Same here: Ubuntu 24.04.4, Cursor 3.0.16, [https://api.us-west-2.modal.direct/v1/chat/completions](https://api.us-west-2.modal.direct/v1/chat/completions) also: [https://api.z.ai/api/coding/paas/v4](https://api.z.ai/api/coding/paas/v4) Models: GLM-5-FP8 (modal.direct) , GLM-5 + GLM-5.1 (z.ai) Model GLM-5-TURBO seems to work correct at the moment. ---
**Author:** ![Ryan\_Guadalupe](https://avatars.discourse-cdn.com/v4/letter/r/41988e/32.png) [@Ryan\_Guadalupe](https://forum.cursor.com/u/Ryan_Guadalupe)\ **Post date:** [April 11, 2026, 4:19am UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/9 "2026-04-11T04:19:32Z")
**Model:** `zai-org/GLM-5.1-FP8` via Modal Research **Request ID:** `2f1f977f-0843-4710-8e59-cb232753dd28` **Date:** 2026-04-11 **OS:** Windows 10 (x64) **Cursor Version:** Latest * * * ### Summary When using GLM-5.1-FP8 via Modal Research as the agent model in Cursor, all tool calls (Read, Glob, Shell) fail silently — they return empty results with no error and no output. However, the **same model, same API key, and same URL work correctly** when used through the Roo Code extension inside Cursor. ### What Works ✅ - **Roo Code extension** (v3.52.0) with provider `openai` → GLM-5.1 tool calls execute correctly and return results - **Roo Code** uses the endpoint `/v1/chat/completions` with OpenAI-compatible function calling format ### What Doesn’t Work ❌ - **Cursor’s native agent** with the same model → Read, Glob, Shell all return empty (no error, no content) - Cursor’s agent appears to either use a different function calling format or process tool call responses differently than Roo Code ### System Checks (All Passed) - Drive E: Fixed NTFS, online, read/write ✅ - File existence and permissions ✅ (FullControl for all groups) - Files readable via PowerShell ✅ - Cursor process running normally ✅ - User `hgartemis` is owner of project folder ✅ This confirms the issue is **not** related to file access, permissions, indexing, or the local environment. ### Key Observation The fact that Roo Code successfully executes tool calls with the exact same Modal endpoint and model strongly suggests that: 1. Modal’s API **does** support OpenAI-compatible function calling via `/v1/chat/completions` 2. The issue is specific to **how Cursor’s native agent sends or processes tool call requests/responses** , not the model’s capability 3. Cursor’s agent may be using a different endpoint (e.g., `/v1/responses`), a different tool call format, or expecting a response structure that differs from what Modal returns ### Reproduction Steps 1. Configure GLM-5.1-FP8 via Modal Research (`https://api.us-west-2.modal.direct/v1`) in Cursor Settings → Models 2. Open any project 3. Ask Cursor’s native agent to read a file, search for files, or run a shell command 4. All tool calls return empty — no content, no errors 5. Install Roo Code extension in Cursor 6. Configure the same Modal URL + API key with provider `openai` (not `openai-native`) 7. Ask Roo Code to perform the same file/shell operations 8. Tool calls work correctly and return results ### Request for the Cursor Team Could you investigate how Cursor’s native agent handles tool calls with custom OpenAI-compatible providers? There seems to be a compatibility difference between Cursor’s agent implementation and extensions like Roo Code that use the standard `/v1/chat/completions` + function calling format. Specifically: - Does Cursor’s agent use `/v1/responses` instead of `/v1/chat/completions` for tool calls? - Is there a difference in how the tool call response schema is parsed vs. the standard OpenAI format? - Could there be a fallback or compatibility mode for providers that don’t support the Responses API? Request ID for server-side debugging: `2f1f977f-0843-4710-8e59-cb232753dd28` ---
**Author:** ![Eidan\_Tzdaka](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/eidan_tzdaka/32/67790_2.png) [@Eidan\_Tzdaka](https://forum.cursor.com/u/Eidan_Tzdaka)\ **Post date:** [April 17, 2026, 11:28am UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/10 "2026-04-17T11:28:54Z")
Having the same issue here. I am working with the support team. I think there was a change recently from Cursor. When we pass GLM-5, cursor resolves it as glm-5 while z.ai expects GLM-5. I think the solution should be extremely easy since GLM-5 used to work! ---
**Author:** ![Eidan\_Tzdaka](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/eidan_tzdaka/32/67790_2.png) [@Eidan\_Tzdaka](https://forum.cursor.com/u/Eidan_Tzdaka)\ **Post date:** [April 20, 2026, 2:05pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/11 "2026-04-20T14:05:59Z")
## Found a solution from a different forum. adding the following skill: name: glm-native-workspace description: Enforces Cursor-native workspace operations for z.ai GLM models (GLM-5, GLM-5.1, GLM-5-Turbo, and other GLM-\* variants). Forbids shell commands for listing, searching, reading, creating, editing, or deleting files and folders, requiring native Cursor tools (read\_file, edit\_file, list\_dir, codebase\_search, grep, glob) instead. Use when the user selects a GLM or z.ai model, mentions z.ai or GLM, or requests a native-IDE-only workflow without terminal file operations. -– **# GLM Native Workspace Operations** **## Purpose** This skill applies to every conversation with z.ai GLM models (GLM-5, GLM-5.1, GLM-5-Turbo, and other `GLM-*` variants). It forces the agent to use Cursor’s native IDE tools for all workspace exploration and file modifications, rather than shelling out to the terminal. **## Mandatory Pre-Action Step** Before taking ANY action, review the available tools and choose the appropriate native Cursor tool for the job. Avoid manual CMD, Bash, or PowerShell execution for file or folder operations. **## Strictly Forbidden** Under NO circumstances should the agent use terminal commands, shell scripts, Command Prompt, or PowerShell to read, write, modify, delete, or list files and folders. Do NOT use terminal commands such as: | Purpose | Forbidden Commands | |---------|--------------------| | Listing / Searching | `ls`, `dir`, `tree`, `find`, `grep`, `rg`, `Get-ChildItem` | | Folder Operations | `mkdir`, `rmdir`, `rm -rf`, `New-Item`, `Remove-Item` | | File Reading | `cat`, `head`, `tail`, `less`, `more`, `Get-Content` | | File Writing / Editing | `echo \>`, `\>`, `\>\>`, `vim`, `nano`, `sed`, `awk`, `Set-Content`, `Out-File` | **## Required Native Tools** Always route workspace work through Cursor’s native tool surface: | Task | Use Native Tool | |------|-----------------| | List folder contents | `list_dir` / workspace file explorer | | Find files by name/pattern | `glob_file_search` | | Search file contents | `grep` / `codebase_search` | | Read a file | `read_file` | | Create or edit a file | `edit_file` / `write` | | Delete a file | `delete_file` | | Understand code semantically | `codebase_search` | **## Allowed Terminal Use** Terminal execution is reserved ONLY for: - Running applications (e.g. `python app.py`, `node server.js`) - Executing tests (e.g. `pytest`, `npm test`) - Starting local servers or dev watchers - Package management (e.g. `pip install`, `npm install`, `uv sync`) - Version control commands explicitly requested by the user (e.g. `git status`, `git commit`) If a task requires a shell command outside this list, stop and use the native tool equivalent instead. **## Decision Flow** 1. Need to inspect or modify the workspace? → Use a native tool. 2. Unsure which native tool applies? → Re-check the available tool list before acting. 3. About to type `ls`, `cat`, `mkdir`, `echo \>`, `sed`, etc.? → STOP. Switch to the native tool. 4. Shell command is purely about running code, tests, servers, or installers? → Proceed via terminal. **## Examples** **\*\*Correct\*\*** - “I need to see what’s in `src/`.” → Call `list_dir` on `src/`. - “Open `README.md`.” → Call `read_file` on `README.md`. - “Create `src/utils/logger.ts`.” → Call `edit_file` / `write` with the new path. - “Find every usage of `fetchUser`.” → Call `grep` or `codebase_search`. - “Run the test suite.” → Run `pytest` or `npm test` in the terminal. **\*\*Incorrect\*\*** - Running `ls src/` to inspect a folder. - Running `cat README.md` to read a file. - Running `mkdir -p src/utils && echo “…” \> src/utils/logger.ts` to scaffold a file. - Running `grep -r “fetchUser” .` instead of the native grep/search tool. **## Compliance Checklist** Before responding, confirm: - [] No forbidden shell command was used for file/folder ops. - [] Every file read went through `read_file`. - [] Every file or folder mutation went through `edit_file` / `write` / `delete_file`. - [] Every search went through `grep`, `codebase_search`, or `glob_file_search`. - [] Terminal use, if any, was limited to running apps, tests, servers, or package managers. and GLM works! ---
**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\ **Post date:** [May 12, 2026, 2:06pm UTC](https://forum.cursor.com/t/bug-glm-5-modal-research-agent-tool-calls-return-empty-no-output-no-error/157099/13 "2026-05-12T14:06:31Z")
Closed on May 12, 2026, 2:06pm UTC This topic was automatically closed 22 days after the last reply. New replies are no longer allowed.