Register an AWS Bedrock AgentCore MCP Server

Connect an Amazon Bedrock AgentCore runtime as a remote MCP server using AWS SigV4 authentication.

Amazon Bedrock AgentCore runtimes expose an MCP endpoint that requires AWS Signature Version 4 (SigV4) on every request. TrueFoundry stores shared AWS credentials on the MCP server and signs upstream calls in the MCP Gateway — users do not complete a Connect / OAuth consent flow.

This guide covers registering an existing AgentCore runtime that uses IAM inbound auth. Choose one credential type: AWS Access Key or AWS Assumed Role.

Guide to registering an AgentCore MCP server

1. Open your AgentCore runtime in AWS

   1. Sign in to the AWS Console in the region where your runtime lives (for example US East (N. Virginia) / us-east-1).
   2. Open Amazon Bedrock → AgentCore → Build → Runtime.
   3. In Runtime resources, click the runtime you want to connect (for example an IAM-backed MCP runtime such as tfy_mcp_iam or tfy_test_mcp_server). Status should be Ready.

   

   Use Build → Runtime, not Discover → Registry. The MCP invoke URL is built from the Runtime ARN (…:runtime/…), not a registry ARN.

2. Copy the Runtime ARN and build the MCP URL

   1. On the runtime detail page, copy the Runtime ARN.

   

   Example ARN:

   arn:aws:bedrock-agentcore:us-east-1:123456789012:runtime/my-runtime-abc123
   

   2. Build the MCP URL with this template:

   https://bedrock-agentcore.{region}.amazonaws.com/runtimes/{urlencoded-runtime-ARN}/invocations?qualifier=DEFAULT
   

   The ARN must be percent-encoded in the path (: → %3A, / → %2F). TrueFoundry’s gateway signs the URL as stored — it does not encode the ARN for you.

   Encode it in a shell:

   python3 -c 'from urllib.parse import quote; print(quote("arn:aws:bedrock-agentcore:us-east-1:123456789012:runtime/my-runtime-abc123", safe=""))'
   

   Example result:

   https://bedrock-agentcore.us-east-1.amazonaws.com/runtimes/arn%3Aaws%3Abedrock-agentcore%3Aus-east-1%3A123456789012%3Aruntime%2Fmy-runtime-abc123/invocations?qualifier=DEFAULT
   

   The region in the URL, the region in the ARN, and the AWS Region you select later in TrueFoundry must all match.

3. Configure AWS credentials

   Pick one credential type. Access keys are long-lived IAM user keys stored on the MCP server. Assumed role uses STS (Recommended): the AI Gateway assumes your IAM role and signs with temporary credentials.

   AWS Assumed Role (Recommended)

   Do not create customer access keys. The gateway assumes your IAM role and signs with temporary STS credentials.

   1. In AWS Console, open IAM → Roles → Create role.
   2. Attach a policy that allows invoke on your runtime ARN (same bedrock-agentcore:InvokeAgentRuntime statement as the access-key path).
   3. Set the role trust policy so the TrueFoundry AI Gateway role can call sts:AssumeRole. Use the gateway role ARN for your deployment:

   SaaS

   arn:aws:iam::<tfy-aws-account-id>:role/<tfy-role-name>
   

   On-prem

   arn:aws:iam::<your-aws-account-id>:role/<account-prefix>-truefoundry-<role-name>
   

   Example trust policy (SaaS):

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
           "AWS": "arn:aws:iam::123456789012:role/tfy-role-1"
         },
         "Action": "sts:AssumeRole"
       }
     ]
   }
   

   4. Copy the role ARN (for example arn:aws:iam::123456789012:role/AgentCoreRole).
   5. Optionally store the ARN as a TrueFoundry secret and use the tfy-secret:// FQN in the form.

   AWS Access Key

   You need IAM access key ID and secret.

   1. In AWS Console, open IAM → Users.
   2. Click Create user and give it a name (for example tfy-mcp-agentcore).
   3. On Set permissions, choose Attach policies directly.
   4. Attach a policy that allows invoke on your runtime ARN. Example:

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Action": "bedrock-agentcore:InvokeAgentRuntime",
         "Resource": "arn:aws:bedrock-agentcore:us-east-1:123456789012:runtime/my-runtime-abc123"
       }
     ]
   }
   

   For a quick local test you can temporarily attach AdministratorAccess, then remove it after you create keys.

   

   5. Finish Create user.
   6. Open the new user → Security credentials.
   7. Under Access keys, click Create access key.
   8. Choose Application running outside AWS → Next → Create access key.
   9. Copy Access key and Secret access key now. The secret is shown only once.

   Do not paste raw keys into git, screenshots, or public docs. Prefer storing them in TrueFoundry Secrets and referencing them by FQN.

   10. In TrueFoundry, open Secrets and create (or reuse) a secret group — for example agentcore-aws.
   11. Add two secrets:
       • Key: AWS_ACCESS_KEY_ID → value: your IAM access key ID
       • Key: AWS_SECRET_ACCESS_KEY → value: your IAM secret access key

   See Manage secrets for the full UI flow.

   12. Note each secret’s FQN:

   tfy-secret://<tenant>:<secret-group>:<secret-key>
   

   Example:

   tfy-secret://truefoundry:agentcore-aws:AWS_ACCESS_KEY_ID
   tfy-secret://truefoundry:agentcore-aws:AWS_SECRET_ACCESS_KEY
   
4. Register the remote MCP server in TrueFoundry

   1. Go to MCP Gateway → Add Server → Connect any Remote MCP Server.
   2. Set URL to the encoded AgentCore MCP URL from earlier.
   3. Add Collaborators as needed.
   4. Under Auth Data, select AWS SigV4.
   5. Set AWS Region to the same region as the runtime (for example us-east-1).
   6. Set Credential Type to the option you configured above and fill in:

   

   AWS Assumed Role (Recommended)

   Field	Value
   Credential Type	AWS Assumed Role
   AWS Assumed Role ARN	arn:aws:iam::123456789012:role/AgentCoreRole or a tfy-secret:// FQN

   Do not enter access keys when assumed role is selected.

   AWS Access Key

   Field	Value
   Credential Type	AWS Access Key
   AWS Access Key ID	tfy-secret://…:AWS_ACCESS_KEY_ID (or the raw key for a quick test)
   AWS Secret Access Key	tfy-secret://…:AWS_SECRET_ACCESS_KEY (or the raw secret for a quick test)

   7. Click Add MCP Server (or Update).
5. Optional: apply via manifest / API

   AWS Access Key

   type: mcp-server/remote
   name: my-agentcore-mcp
   url: https://bedrock-agentcore.us-east-1.amazonaws.com/runtimes/arn%3Aaws%3A.../invocations?qualifier=DEFAULT
   auth_data:
     type: aws-sigv4
     region: us-east-1
     auth:
       type: aws-access-key
       access_key_id: tfy-secret://truefoundry:agentcore-aws:AWS_ACCESS_KEY_ID
       secret_access_key: tfy-secret://truefoundry:agentcore-aws:AWS_SECRET_ACCESS_KEY