AWS Bedrockでリランキングを行う

{
    "Version":"2012-10-17", 
    "Statement":
    [
        {
            "Sid": "Statement1", 
            "Effect": "Allow", 
            "Action": [
                "bedrock:InvokeModel",
                "bedrock:InvokeModelWithResponseStream"
            ], 
            "Resource": [
                "arn:aws:bedrock:ap-northeast-1::foundation-model/cohere.rerank-v3-5:0",
                "arn:aws:bedrock:ap-northeast-1::foundation-model/amazon.rerank-v1:0"
            ]
        }
    ]
}

composer require aws/aws-sdk-php

/**
 * テキストの関連度合いをrerankingモデルを通してランキング順に並べる
 * @param string $query クエリに対して
 * @param string[] $documents どのドキュメントが似てるか
 * @param int $limit 上位X件を取得
 * @return array array({index: int, relevance_score: float})
 */
public function reranking(string $query, array $documents, int $limit = 5): array
{
    $client = new BedrockRuntimeClient([
        'version' => '2023-09-30',
        'region' => 'ap-northeast-1',
        'credentials' => [
            'key' => config('登録したアクセスキーの名前'),
            'secret' => config('登録したシークレットアクセスキーの名前'),
        ],
    ]);

    $response = $client->invokeModel([
        'contentType' => 'application/json',
        'body' => json_encode([
            'query' => $query,
            'documents' => $documents,
            'top_n' => $limit,
            'api_version' => 2
        ]),
        'modelId' => 'cohere.rerank-v3-5:0',
    ]);

    $response_body = json_decode($response['body'], true);

    return $response_body['results'];
}

$response = $client->invokeModel([
    'contentType' => 'application/json',
    'body' => json_encode([
        'query' => $query,
        'documents' => $documents,
        'top_n' => $limit,
    ]),
    'modelId' => 'amazon.rerank-v1:0',
]);
$response_body = json_decode($response['body'], true);