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AWS MCP Server - AWS Sign-In
OverviewPrerequisitesSupported Redirect URIs for DCRConnect an agent to AWS MCP ServerAuthorization modelsOAuth resource typesToken lifecycleManaging OAuth tokensMonitoring OAuth activityTroubleshootingRelated topics

AWS MCP Server

Overview

AWS MCP Server supports OAuth authorization through AWS Sign-In. With OAuth authorization, agents can access AWS using the same identities, permissions, and governance model that you already use with the AWS Management Console and AWS CLI. When you authorize an agent, it can access AWS MCP Server on your behalf. Authorization does not grant the agent additional AWS permissions.

Use this guide to configure OAuth access to AWS MCP Server. It covers supported authorization models, required IAM permissions, and how to govern and monitor OAuth access.

For more information about OAuth support in AWS Sign-In, see Sign-In with OAuth 2.0.

Prerequisites

Before connecting an agent to AWS MCP Server, make sure that:

  • Your IAM identity has the required permissions for OAuth authorization.

  • Your agent supports the Model Context Protocol (MCP).

  • Your agent supports OAuth 2.1 authorization.

Grant the required permissions by attaching the AWS managed policy:

aws iam attach-role-policy \
  --role-name MyRole \
  --policy-arn arn:aws:iam::aws:policy/AWSMCPSignInOAuthAccessPolicy

This managed policy grants:

  • signin:AuthorizeOAuth2Access

  • signin:CreateOAuth2Token

If you authenticate as the AWS account root user, no additional IAM permissions are required.

Supported Redirect URIs for DCR

Agents can register with AWS Sign-In and use one or more approved redirect URIs during the OAuth authorization process.

OAuth client Redirect URI(s)
Localhost localhost, 127.0.0.1
Claude https://claude.ai/*
Cursor Desktop cursor://anysphere.cursor-mcp/oauth/callback
Cursor Web https://www.cursor.com/agents/mcp/oauth/callback
Visual Studio Code vscode://*
Visual Studio Code (Web) https://vscode.dev/*
ChatGPT https://chatgpt.com/*
ChatGPT Connectors https://chatgpt.com/connector_platform_oauth_redirect
Replit https://replit.com/
Lovable https://lovable.app/*
Lovable Developer https://lovable.dev/*
Vercel v0 https://api.v0.dev/v1/mcp-servers/oauth/callback

Connect an agent to AWS MCP Server

The steps to configure an OAuth-compatible agent vary depending on the application. For instructions for supported agents, see the AWS MCP Server Guide.

The general workflow is:

  1. Configure the AWS MCP Server endpoint.

  2. Authenticate through AWS Sign-In or obtain an OAuth access token programmatically.

  3. Approve the authorization request (interactive flow only).

  4. Begin invoking tools provided by AWS MCP Server.

Authorization models

AWS MCP Server supports the authorization models provided by AWS Sign-In.

Interactive authorization

Interactive authorization is intended for developers using agents on local workstations.

When an agent requires authorization:

  1. The agent redirects the user to AWS Sign-In.

  2. The user authenticates using their AWS identity.

  3. The user reviews and approves the authorization request.

  4. AWS Sign-In issues OAuth access and refresh tokens.

  5. The agent accesses AWS MCP Server on the user's behalf.

Required IAM permissions:

  • signin:AuthorizeOAuth2Access

  • signin:CreateOAuth2Token

Non-interactive authorization

Non-interactive authorization uses the OAuth 2.0 client credentials grant. It is intended for agents and applications that already possess AWS credentials and cannot perform browser-based authentication.

Applications authenticate using existing AWS Signature Version 4 (SigV4) credentials and obtain OAuth access tokens through the CreateOAuth2TokenWithIAM API.

Unlike the interactive flow, only access tokens are issued. Applications request a new access token when the current token expires.

Required IAM permission:

  • signin:CreateOAuth2Token

The following example shows how to obtain an access token using the AWS CLI:

aws signin create-oauth2-token-with-iam \
    --grant-type client_credentials \
    --resource aws-mcp.amazonaws.com \
    --region us-east-1

OAuth resource types

AWS Sign-In represents OAuth authorization targets and public OAuth clients as IAM resources. You reference these resources in IAM policies to grant or control OAuth authorization.

The following resource types are currently supported.

Resource type ARN format Description
AWS MCP Server arn:aws:signin:region:account-id:service-principal/aws-mcp.amazonaws.com Represents the AWS MCP Server. Use this resource to grant or control OAuth authorization for applications that access AWS MCP Server.
OAuth public client (same-device) arn:aws:signin:region:account-id:oauth2/public-client/localhost Represents the AWS CLI public OAuth client for same-device authorization. Use this resource with aws login, where the browser and AWS CLI run on the same device.
OAuth public client (cross-device) arn:aws:signin:region:account-id:oauth2/public-client/remote Represents the AWS CLI public OAuth client for cross-device authorization. Use this resource with aws login --remote, where authentication is completed on a separate device.

Token lifecycle

AWS Sign-In manages the lifecycle of OAuth tokens issued for AWS MCP Server.

Token Description
Interactive access token Valid for up to one hour. Automatically refreshed while the refresh token remains valid.
Non-interactive access token Valid for the shorter of one hour or the remaining AWS session duration. Applications request a new token after expiration.
Refresh token Issued only for interactive authorization. Allows applications to obtain new access tokens without requiring the user to sign in again. Refresh tokens are rotated and single-use.

Managing OAuth tokens

AWS Sign-In provides APIs for validating and managing OAuth authorizations.

API Purpose
IntrospectOAuth2Token Returns metadata describing an OAuth token.
RevokeOAuth2Token Revokes a refresh token.

Monitoring OAuth activity

OAuth-related activities are recorded in AWS CloudTrail.

CloudTrail records events including:

  • OAuth authorization requests

  • OAuth token issuance

  • Token introspection

  • Token revocation

CloudTrail also records the OAuth client, redirect URI, authorization flow, AWS MCP Server resource, and associated AWS Sign-In session, allowing administrators to correlate AWS API activity with the originating OAuth authorization.

Example CloudTrail events are available for:

  • AuthorizeOAuth2Access

  • CreateOAuth2Token

Example – AuthorizeOAuth2Access event:

{
    "eventVersion": "1.11",
    "userIdentity": {
        "type": "AssumedRole",
        "principalId": "AROAEXAMPLE:testuser",
        "arn": "arn:aws:sts::111111111111:assumed-role/Admin/testuser",
        "accountId": "111111111111",
        "sessionContext": {
            "sessionIssuer": {
                "type": "Role",
                "principalId": "AROAEXAMPLE",
                "arn": "arn:aws:iam::111111111111:role/Admin",
                "accountId": "111111111111",
                "userName": "Admin"
            },
            "attributes": {
                "creationDate": "2026-06-09T05:06:39Z",
                "mfaAuthenticated": "false"
            }
        }
    },
    "eventTime": "2026-06-09T05:09:00Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "AuthorizeOAuth2Access",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "192.0.2.1",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) ...",
    "requestParameters": {
        "resource": "https://aws-mcp.us-west-2.api.aws/mcp",
        "redirect_uri": "http://127.0.0.1:60432/oauth/callback",
        "code_challenge_method": "S256",
        "client_id": "arn:aws:signin:us-west-2::external-client/dcr/b3f2c8a1-9d4e-4f7a-8c6b-2e1f5a3d9b7c"
    },
    "responseElements": null,
    "additionalEventData": {
        "success": "true"
    },
    "requestID": "4fb4ff7b-6yu7-9090-78i9-9c0088a65134",
    "eventID": "bb05b222-31ec-4237-b8e7-8eb26d4fd48b",
    "readOnly": true,
    "eventType": "AwsApiCall",
    "managementEvent": true,
    "recipientAccountId": "111111111111",
    "eventCategory": "Management",
    "tlsDetails": {
        "tlsVersion": "TLSv1.3",
        "cipherSuite": "TLS_AES_128_GCM_SHA256",
        "clientProvidedHostHeader": "us-west-2.oauth.signin.aws"
    }
}

Example – CreateOAuth2Token event:

{
    "eventVersion": "1.11",
    "userIdentity": {
        "type": "AssumedRole",
        "principalId": "AROAEXAMPLE:testuser",
        "arn": "arn:aws:sts::111111111111:assumed-role/Admin/testuser",
        "accountId": "111111111111",
        "sessionContext": {
            "sessionIssuer": {
                "type": "Role",
                "principalId": "AROAEXAMPLE",
                "arn": "arn:aws:iam::111111111111:role/Admin",
                "accountId": "111111111111",
                "userName": "Admin"
            },
            "attributes": {
                "creationDate": "2026-06-09T05:06:39Z",
                "mfaAuthenticated": "false"
            },
            "signInSessionArn": "arn:aws:signin:us-west-2:111111111111:session/daff060f-7871-4ab6-92cd-a07bbdabe61a"
        }
    },
    "eventTime": "2026-06-09T05:10:04Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "CreateOAuth2Token",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "192.0.2.1",
    "userAgent": "curl/8.7.1",
    "requestParameters": {
        "resource": "https://aws-mcp.us-west-2.api.aws/mcp",
        "client_id": "arn:aws:signin:us-west-2::external-client/dcr/b3f2c8a1-9d4e-4f7a-8c6b-2e1f5a3d9b7c"
    },
    "responseElements": null,
    "additionalEventData": {
        "signInSessionArn": "arn:aws:signin:us-west-2:111111111111:session/daff060f-7871-4ab6-92cd-a07bbdabe61a",
        "grant_type": "refresh_token",
        "success": "true"
    },
    "requestID": "44d6d7ce-e4r5-4cbf-0909-bfb8a8295a76",
    "eventID": "f79cc63f-b383-4e3c-a1e5-97c7db1ab833",
    "readOnly": true,
    "eventType": "AwsApiCall",
    "managementEvent": true,
    "recipientAccountId": "111111111111",
    "eventCategory": "Management",
    "tlsDetails": {
        "tlsVersion": "TLSv1.3",
        "cipherSuite": "TLS_AES_128_GCM_SHA256",
        "clientProvidedHostHeader": "us-west-2.oauth.signin.aws"
    }
}

Additional audit events and logging details for calls made using OAuth access tokens to the AWS MCP Server can be found in the AWS MCP Server CloudTrail logging guide.

Troubleshooting

Permission denied when connecting to AWS MCP Server

Verify that your IAM identity has the signin:AuthorizeOAuth2Access and signin:CreateOAuth2Token permissions for the AWS MCP Server authorization grant resource.

Access token expired

Interactive authorization automatically refreshes access tokens while the associated refresh token remains valid. If the refresh token has expired or been revoked, authenticate again through your agent.

For non-interactive authorization, you can request a new access token from the token endpoint.

Invalid target resource

When calling CreateOAuth2TokenWithIAM, verify that the resource parameter identifies a supported target service. For AWS MCP Server, use the AWS MCP Server service principal.

Agent cannot register as an OAuth client

Only approved agents can register through Dynamic Client Registration (DCR). If you are developing an MCP-compatible agent, contact AWS support.

OAuth condition key policy is not taking effect

Verify that the condition key applies to the IAM action being evaluated. Some condition keys are supported only by specific OAuth actions. For more information, see Sign-In with OAuth 2.0.

Session revoked but the agent still has access

Revoking a refresh token immediately prevents new access tokens from being issued. Existing access tokens remain valid until they expire (up to one hour).

For immediate containment, apply an IAM policy using the aws:SignInSessionArn global condition key to deny requests associated with the affected sign-in session.