Cross-Account Bedrock Access: Platform Teams Without Shared Keys

org
├── platform-ai (Bedrock, Guardrails, KMS, CloudTrail lake)
├── product-payments (assume role → invoke)
└── product-growth (assume role → invoke)

{
  "Version": "2012-10-17",
  "Statement": [{
    "Effect": "Allow",
    "Principal": { "AWS": "arn:aws:iam::111111111111:root" },
    "Action": "sts:AssumeRole",
    "Condition": {
      "StringEquals": { "sts:ExternalId": "payments-prod-extid" },
      "IpAddress": { "aws:SourceIp": "10.0.0.0/8" }
    }
  }]
}

{
  "Effect": "Allow",
  "Action": [
    "bedrock:InvokeModel",
    "bedrock:InvokeModelWithResponseStream",
    "bedrock:Converse",
    "bedrock:ConverseStream"
  ],
  "Resource": [
    "arn:aws:bedrock:*::foundation-model/anthropic.*",
    "arn:aws:bedrock:*:999999999999:inference-profile/payments-*"
  ],
  "Condition": {
    "StringEquals": {
      "aws:RequestTag/team": "payments",
      "aws:RequestTag/env": ["prod", "staging"]
    }
  }
}

import { STSClient, AssumeRoleCommand } from "@aws-sdk/client-sts";
import { BedrockRuntimeClient, ConverseCommand } from "@aws-sdk/client-bedrock-runtime";
import { fromTemporaryCredentials } from "@aws-sdk/credential-providers";

export function bedrockForTeam(team: string) {
  return new BedrockRuntimeClient({
    region: "us-east-1",
    credentials: fromTemporaryCredentials({
      params: {
        RoleArn: process.env.BEDROCK_CONSUMER_ROLE_ARN!,
        RoleSessionName: `bedrock-${team}`,
        ExternalId: process.env.BEDROCK_EXTERNAL_ID!,
        Tags: [
          { Key: "team", Value: team },
          { Key: "env", Value: process.env.APP_ENV! },
        ],
      },
    }),
  });
}