feat(providers/amazon): add BedrockRerankOperator for document reranking

[gauravSsinha]

Description

Adds BedrockRerankOperator that uses the Bedrock Agent Runtime Rerank API to score and reorder documents by relevance to a query.

Motivation

Reranking is a critical step in production RAG pipelines — it improves answer quality by reordering retrieved documents before passing them to a generative model. Amazon Bedrock now supports reranking via the Cohere Rerank model, but there's no Airflow operator for it.

Changes

Added BedrockRerankOperator to providers/amazon/src/airflow/providers/amazon/aws/operators/bedrock.py:

• Uses BedrockAgentRuntimeHook (bedrock-agent-runtime client)
• Configurable model_id (defaults to cohere.rerank-v3-5:0)
• number_of_results parameter to limit returned documents
• All key parameters are template-able
• Returns ranked results with relevance scores

Example Usage

rerank = BedrockRerankOperator(
    task_id='rerank_results',
    query='What is serverless computing?',
    documents=[{'textDocument': {'text': doc}} for doc in retrieved_docs],
    model_id='cohere.rerank-v3-5:0',
    number_of_results=5,
)

Related

• Bedrock Rerank API: https://docs.aws.amazon.com/bedrock/latest/APIReference/API_agent-runtime_Rerank.html
• Existing operators: BedrockRaGOperator, BedrockRetrieveOperator

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Was generative AI tooling used to co-author this PR?

• Yes
  Generated-by: Kiro (AI IDE)

[boring-cyborg]

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[vincbeck]

Please create unit tests associated to this operator

[Srabasti]

Congratulations on your first PR! Static checks are failing @gauravSsinha
Please run prek locally to ensure no errors and then commit your branch to repo after rebasing.

[potiuk]

@gauravSsinha A few things need addressing before review — see our Pull Request quality criteria.

• ❌ Pre-commit / static checks. See docs.
• ❌ Other failing CI checks. See docs.

No rush.

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