# Error trying to add an LLM-as-judge Evaluator

**URL:** <https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176>\
**Category:** Observability & Evals\
**Created:** [August 15, 2025, 3:31pm UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176 "2025-08-15T15:31:23Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![DanielJonesEB](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/danieljoneseb/32/612_2.png) [@DanielJonesEB](https://forum.langchain.com/u/DanielJonesEB)\
**Post date:** [August 15, 2025, 3:31pm UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176/1 "2025-08-15T15:31:23Z")

</div>

When trying to create an LLM-as-judge evaluator on an experiment, I get the following error message pop up in the bottom-right of the window, after clicking the “Save” button:

”Failed to save evaluator: Manifest type langchain.schema.runnable.RunnableSequence is not supported”

Any ideas what might be wrong or how to fix it? I’m just trying to do a ‘hello world’ style experiment.

---

<div class="post-metadata">

**Author:** ![madams0013](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/madams0013/32/188_2.png) [@madams0013](https://forum.langchain.com/u/madams0013)\
**Post date:** [August 15, 2025, 4:45pm UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176/2 "2025-08-15T16:45:53Z")

</div>

Hi Daniel! Do you mind adding the steps you took to get this error to help us reproduce the issue?

---

<div class="post-metadata">

**Author:** ![sean-weber-cambri](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/sean-weber-cambri/32/633_2.png) [@sean-weber-cambri](https://forum.langchain.com/u/sean-weber-cambri)\
**Post date:** [August 18, 2025, 11:36am UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176/3 "2025-08-18T11:36:51Z")

</div>

I’m getting the same issue

1. Create a new evaluator by selecting any prebuilt evaluator like “Correctness”
2. Change the model configuration
  1. Provider: Amazon Bedrock
  2. Model: eu.anthropic.claude-sonnet-4-20250514-v1:0
  3. API: InvokeModel
  4. Region: eu-west-1

3. Try to save the evaluator

---

<div class="post-metadata">

**Author:** ![madams0013](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/madams0013/32/188_2.png) [@madams0013](https://forum.langchain.com/u/madams0013)\
**Post date:** [August 20, 2025, 8:38pm UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176/4 "2025-08-20T20:38:05Z")

</div>

We’ve identified a fix for this and it will be live soon. Thanks for reporting!

---

<div class="post-metadata">

**Author:** ![madams0013](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/madams0013/32/188_2.png) [@madams0013](https://forum.langchain.com/u/madams0013)\
**Post date:** [August 21, 2025, 8:29pm UTC](https://forum.langchain.com/t/error-trying-to-add-an-llm-as-judge-evaluator/1176/5 "2025-08-21T20:29:34Z")

</div>

The fix is live!