AWS MCP Server drops proxy, impacting cross-account switching with OAuth 2.1

AWS has updated its MCP Server to support OAuth 2.1, removing the need for a local proxy for many clients. This change, effective July 9, 2026, allows OAuth-compatible tools like Claude Code, Cursor, and GitHub Copilot to connect directly to the AWS MCP Server using bearer tokens. However, a significant drawback is the loss of cross-account profile switching, a critical feature for organizations managing multiple AWS accounts, which now requires re-authentication. AI

IMPACT This change impacts developer workflows for AI tools interacting with AWS, potentially requiring re-authentication for cross-account operations.

RANK_REASON This item describes a change to an AWS service's authentication mechanism and its impact on client tools, rather than a core AI model release or research.

Read on dev.to — MCP tag →

• Agent Toolkit
• S3
• AWS MCP Server
• AWSMCPSignInOAuthAccessPolicy
• aws-mcp.us-east-1.api.aws
• Claude Code
• Cursor
• Gemini CLI
• GitHub Copilot
• IAM
• July 9, 2026
• MCP Proxy for AWS
• OAuth 2.1

• product
• infra

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