Interleave thinking not supported on Bedrock API

[MaxPaz]

Checked other resources

• This is a bug, not a usage question. For questions, please use the LangChain Forum (https://forum.langchain.com/).
• I added a very descriptive title to this issue.
• I searched the LangChain.js documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain.js rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

Anthropic interleave-thinking not support on JS

Python Example:
thinking={
"type": "enabled",
"budget_tokens": 10000
},
# Enable interleaved thinking with beta header
extra_headers={
"anthropic-beta": "interleaved-thinking-2025-05-14"
},

Error Message and Stack Trace (if applicable)

No response

Description

Anthropic interleave thinking is not available with Langchain - Bedrock Converse API.
In python this can be used with a workaround (langchain-ai/langchain-aws#492), but in JS this is not available.
This will allow Langchain/AWS users to interact with latest Claude features w/Bedrock ConverseAPI

System Info

.