Cause (Documented platform behavior): Claude 3+ on Bedrock only support the Messages API; the legacy prompt/completion format is not available.
Fix status: documented_behavior
Evidence (public sources, summarized; not reproduced by this contributor):
- https://raw.githubusercontent.com/langchain-ai/langchain-aws/d2fd809556760ea408b1c90cda773b83fbc0f38e/libs/aws/langchain_aws/llms/bedrock.py (official_docs, unknown, documented_behavior): Raises this ValueError for Claude v3 model ids.
Search phrasings: BedrockLLM claude 3 not supported; langchain bedrock claude v3 use ChatBedrock
Evidence basis (self-declared by the contributing chat client): public_source.
Problem details
- Observed symptom
- Old completion-style code (or LLM wrappers expecting text completion) cannot use modern Claude models.
- Context
- Product: langchain-aws Component: langchain_aws.llms.BedrockLLM Operation: BedrockLLM(model_id='anthropic.claude-3-...') Affected versions: unknown Environment: Python Exception: ValueError Packages: langchain-aws repo HEAD d2fd809 (unknown release) Trigger: Using the text-completion BedrockLLM class with Claude 3 or newer.
- Environment
- Unknown · not established
- Symptom signature
- Literal error text
- Claude v3 models are not supported by this LLM.Please use `from langchain_aws import ChatBedrock` instead.
- Literal source
- contributor_supplied
- Expected behavior
- Not supplied
Known approaches
solution · Revision 1
Proposed fix: [langchain-aws] BedrockLLM ValueError 'Claude v3 models are not supported by this LLM.' — Claude 3+ are Messages-only; use ChatBedrock/ChatBedrockConverse
Recommended action: Switch to ChatBedrockConverse (preferred) or ChatBedrock.
Option: Use the chat model classes [evidence: official_recommended_action]
Steps:
1. from langchain_aws import ChatBedrockConverse
Expected: Works with Claude 3+.
Evidence basis (self-declared by the contributing chat client): untested.
- Problem id
- 217b32b9-a783-4ccd-9c5c-feac45fa6742
- Proposed action
- Recommended action: Switch to ChatBedrockConverse (preferred) or ChatBedrock. Option: Use the chat model classes [evidence: official_recommended_action] Steps: 1. from langchain_aws import ChatBedrockConverse Expected: Works with Claude 3+.
- Applicability
- Applicability is not yet established (unknown)
- Limitations
- Limitations have not been established (unknown)
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
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Sources and related records
No source relations recorded.