Testing: All 5 new unit tests pass; manual verification confirms orphaned tool calls no longer break conversations
Code review: Self-reviewed
Title Prefix:fix:
Changelog Entry
Description
When a native function call (e.g., web search) times out or fails without producing a function_call_output, convert_output_to_messages() emits an assistant message with tool_calls but no following tool role message. All providers (OpenAI, Azure, Google) reject this as invalid, returning "Provider returned error" for every subsequent message in that chat — permanently breaking the conversation.
This is a minimal, targeted fix: after the final flush_pending() call in convert_output_to_messages(), check if the last message is an assistant with tool_calls and append synthetic tool role messages so the conversation remains valid.
Fixed
Orphaned tool calls (function_call without matching function_call_output) no longer corrupt conversation history. Synthetic tool responses with [Tool execution did not return a result] are appended so providers accept the message sequence.
backend/open_webui/utils/misc.py — 11-line addition after flush_pending() in convert_output_to_messages()
backend/open_webui/test/test_convert_output.py — 5 new test cases
Test plan:
Normal flow (function_call + function_call_output) — no change in behavior
Orphaned function_call at end — synthetic tool response added
Multiple orphaned tool calls — all get synthetic responses
Empty output list — returns empty
Output with only messages (no tool calls) — no change
Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.
## 📋 Pull Request Information
**Original PR:** https://github.com/open-webui/open-webui/pull/21941
**Author:** [@maxkuminov](https://github.com/maxkuminov)
**Created:** 2/27/2026
**Status:** ❌ Closed
**Base:** `dev` ← **Head:** `fix/orphaned-tool-calls`
---
### 📝 Commits (10+)
- [`fe6783c`](https://github.com/open-webui/open-webui/commit/fe6783c16699911c7be17392596d579333fb110c) Merge pull request #19030 from open-webui/dev
- [`fc05e0a`](https://github.com/open-webui/open-webui/commit/fc05e0a6c5d39da60b603b4d520f800d6e36f748) Merge pull request #19405 from open-webui/dev
- [`e3faec6`](https://github.com/open-webui/open-webui/commit/e3faec62c58e3a83d89aa3df539feacefa125e0c) Merge pull request #19416 from open-webui/dev
- [`9899293`](https://github.com/open-webui/open-webui/commit/9899293f050ad50ae12024cbebee7e018acd851e) Merge pull request #19448 from open-webui/dev
- [`140605e`](https://github.com/open-webui/open-webui/commit/140605e660b8186a7d5c79fb3be6ffb147a2f498) Merge pull request #19462 from open-webui/dev
- [`6f1486f`](https://github.com/open-webui/open-webui/commit/6f1486ffd0cb288d0e21f41845361924e0d742b3) Merge pull request #19466 from open-webui/dev
- [`d95f533`](https://github.com/open-webui/open-webui/commit/d95f533214e3fe5beb5e41ec1f349940bc4c7043) Merge pull request #19729 from open-webui/dev
- [`a727153`](https://github.com/open-webui/open-webui/commit/a7271532f8a38da46785afcaa7e65f9a45e7d753) 0.6.43 (#20093)
- [`6adde20`](https://github.com/open-webui/open-webui/commit/6adde203cd292a9e3af9c64a2ae36b603fed096a) Merge pull request #20394 from open-webui/dev
- [`f9b0534`](https://github.com/open-webui/open-webui/commit/f9b0534e0c442631d1cb7205169588b9b6204179) Merge pull request #20522 from open-webui/dev
### 📊 Changes
**2 files changed** (+123 additions, -0 deletions)
<details>
<summary>View changed files</summary>
➕ `backend/open_webui/test/test_convert_output.py` (+106 -0)
📝 `backend/open_webui/utils/misc.py` (+17 -0)
</details>
### 📄 Description
# Pull Request Checklist
- [x] **Target branch:** `dev`
- [x] **Description:** See below
- [x] **Testing:** All 5 new unit tests pass; manual verification confirms orphaned tool calls no longer break conversations
- [x] **Code review:** Self-reviewed
- [x] **Title Prefix:** `fix:`
# Changelog Entry
### Description
When a native function call (e.g., web search) times out or fails without producing a `function_call_output`, `convert_output_to_messages()` emits an assistant message with `tool_calls` but no following `tool` role message. All providers (OpenAI, Azure, Google) reject this as invalid, returning "Provider returned error" for **every subsequent message** in that chat — permanently breaking the conversation.
This is a minimal, targeted fix: after the final `flush_pending()` call in `convert_output_to_messages()`, check if the last message is an assistant with `tool_calls` and append synthetic `tool` role messages so the conversation remains valid.
### Fixed
- Orphaned tool calls (function_call without matching function_call_output) no longer corrupt conversation history. Synthetic tool responses with `[Tool execution did not return a result]` are appended so providers accept the message sequence.
Fixes #14577, #12135, #18121, #9435
### Additional Information
**Files changed:**
- `backend/open_webui/utils/misc.py` — 11-line addition after `flush_pending()` in `convert_output_to_messages()`
- `backend/open_webui/test/test_convert_output.py` — 5 new test cases
**Test plan:**
- [x] Normal flow (function_call + function_call_output) — no change in behavior
- [x] Orphaned function_call at end — synthetic tool response added
- [x] Multiple orphaned tool calls — all get synthetic responses
- [x] Empty output list — returns empty
- [x] Output with only messages (no tool calls) — no change
### Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms.
---
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📋 Pull Request Information
Original PR: https://github.com/open-webui/open-webui/pull/21941
Author: @maxkuminov
Created: 2/27/2026
Status: ❌ Closed
Base:
dev← Head:fix/orphaned-tool-calls📝 Commits (10+)
fe6783cMerge pull request #19030 from open-webui/devfc05e0aMerge pull request #19405 from open-webui/deve3faec6Merge pull request #19416 from open-webui/dev9899293Merge pull request #19448 from open-webui/dev140605eMerge pull request #19462 from open-webui/dev6f1486fMerge pull request #19466 from open-webui/devd95f533Merge pull request #19729 from open-webui/deva7271530.6.43 (#20093)6adde20Merge pull request #20394 from open-webui/devf9b0534Merge pull request #20522 from open-webui/dev📊 Changes
2 files changed (+123 additions, -0 deletions)
View changed files
➕
backend/open_webui/test/test_convert_output.py(+106 -0)📝
backend/open_webui/utils/misc.py(+17 -0)📄 Description
Pull Request Checklist
devfix:Changelog Entry
Description
When a native function call (e.g., web search) times out or fails without producing a
function_call_output,convert_output_to_messages()emits an assistant message withtool_callsbut no followingtoolrole message. All providers (OpenAI, Azure, Google) reject this as invalid, returning "Provider returned error" for every subsequent message in that chat — permanently breaking the conversation.This is a minimal, targeted fix: after the final
flush_pending()call inconvert_output_to_messages(), check if the last message is an assistant withtool_callsand append synthetictoolrole messages so the conversation remains valid.Fixed
[Tool execution did not return a result]are appended so providers accept the message sequence.Fixes #14577, #12135, #18121, #9435
Additional Information
Files changed:
backend/open_webui/utils/misc.py— 11-line addition afterflush_pending()inconvert_output_to_messages()backend/open_webui/test/test_convert_output.py— 5 new test casesTest plan:
Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.