Target branch: Verify that the pull request targets the dev branch.
Description: Provide a concise description of the changes made in this pull request down below.
Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
Testing: Perform manual tests to verify the implemented fix/feature works as intended AND does not break any other functionality.
Code review: Have you performed a self-review of your code?
Title Prefix:fix
Changelog Entry
Fixed
Resolved TypeError: cannot pickle '_asyncio.Future' object when using MCP tools by decoupling mcp_clients from the metadata dictionary.
Fixed an IndentationError in backend/open_webui/main.py that prevented server startup.
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/20657
**Author:** [@KoulLife](https://github.com/KoulLife)
**Created:** 1/14/2026
**Status:** ❌ Closed
**Base:** `dev` ← **Head:** `fix/issue-20629-mcp-pickle-error`
---
### 📝 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** (+9 additions, -10 deletions)
<details>
<summary>View changed files</summary>
📝 `backend/open_webui/main.py` (+6 -7)
📝 `backend/open_webui/utils/middleware.py` (+3 -3)
</details>
### 📄 Description
fix: resolve pickle error by decoupling mcp_clients from metadata
## Description
This PR resolves the `TypeError: cannot pickle '_asyncio.Future' object` error that occurs when using MCP tools in chat.
### Changes
1. **Fix Pickling Error**:
- Decoupled `mcp_clients` from the `metadata` dictionary in `backend/open_webui/utils/middleware.py`.
- Updated `backend/open_webui/main.py` to handle `mcp_clients` as a local variable/return value instead of accessing it via the pickled `metadata` object.
2. **Fix Indentation Error**:
- Corrected an `IndentationError` in `backend/open_webui/main.py` (around line 1793) ensuring proper `asyncio.create_task` execution flow.
Fixes #20629
# Pull Request Checklist
- [x] **Target branch:** Verify that the pull request targets the `dev` branch.
- [x] **Description:** Provide a concise description of the changes made in this pull request down below.
- [x] **Changelog:** Ensure a changelog entry following the format of [Keep a Changelog](https://keepachangelog.com/) is added at the bottom of the PR description.
- [x] **Testing:** Perform manual tests to **verify the implemented fix/feature works as intended AND does not break any other functionality**.
- [x] **Code review:** Have you performed a self-review of your code?
- [x] **Title Prefix:** `fix`
# Changelog Entry
### Fixed
- Resolved `TypeError: cannot pickle '_asyncio.Future' object` when using MCP tools by decoupling `mcp_clients` from the metadata dictionary.
- Fixed an `IndentationError` in `backend/open_webui/main.py` that prevented server startup.
### 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.
---
<sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
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📋 Pull Request Information
Original PR: https://github.com/open-webui/open-webui/pull/20657
Author: @KoulLife
Created: 1/14/2026
Status: ❌ Closed
Base:
dev← Head:fix/issue-20629-mcp-pickle-error📝 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 (+9 additions, -10 deletions)
View changed files
📝
backend/open_webui/main.py(+6 -7)📝
backend/open_webui/utils/middleware.py(+3 -3)📄 Description
fix: resolve pickle error by decoupling mcp_clients from metadata
Description
This PR resolves the
TypeError: cannot pickle '_asyncio.Future' objecterror that occurs when using MCP tools in chat.Changes
mcp_clientsfrom themetadatadictionary inbackend/open_webui/utils/middleware.py.backend/open_webui/main.pyto handlemcp_clientsas a local variable/return value instead of accessing it via the pickledmetadataobject.IndentationErrorinbackend/open_webui/main.py(around line 1793) ensuring properasyncio.create_taskexecution flow.Fixes #20629
Pull Request Checklist
devbranch.fixChangelog Entry
Fixed
TypeError: cannot pickle '_asyncio.Future' objectwhen using MCP tools by decouplingmcp_clientsfrom the metadata dictionary.IndentationErrorinbackend/open_webui/main.pythat prevented server startup.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.