Amazon Bedrock AgentCore Samples - [Bug]

**Describe the bug**
when invoking the mcp server i am getting the error:

```
{"resource":{"attributes":{"deployment.environment.name":"bedrock-agentcore:default","aws.local.service":"mcp_server_ac.DEFAULT","service.name":"mcp_server_ac.DEFAULT","cloud.region":"us-east-1","aws.log.stream.names":"runtime-logs","telemetry.sdk.name":"opentelemetry","aws.service.type":"gen_ai_agent","telemetry.sdk.language":"python","cloud.provider":"aws","cloud.resource_id":"arn:aws:bedrock-agentcore:us-east-1:536824385237:runtime/mcp_server_ac-4ZCTFo8gFK/runtime-endpoint/DEFAULT:DEFAULT","aws.log.group.names":"/aws/bedrock-agentcore/runtimes/mcp_server_ac-4ZCTFo8gFK-DEFAULT","telemetry.sdk.version":"1.33.1","cloud.platform":"aws_bedrock_agentcore","telemetry.auto.version":"0.10.0-aws"}},"scope":{"name":"mcp.server.streamable_http_manager"},"timeUnixNano":1753362625074154496,"observedTimeUnixNano":1753362625074227502,"severityNumber":9,"severityText":"INFO","body":"Created new transport with session ID: c361728218964f30b01a32aa7be119c7","attributes":{"otelTraceSampled":true,"code.file.path":"/usr/local/lib/python3.12/site-packages/mcp/server/streamable_http_manager.py","code.function.name":"_handle_stateful_request","otelTraceID":"688230c185d7379b17fa204f6432d847","otelSpanID":"193e2aca79fab1e8","code.line.number":233,"otelServiceName":"mcp_server_ac.DEFAULT"},"flags":1,"traceId":"688230c185d7379b17fa204f6432d847","spanId":"193e2aca79fab1e8"}
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/runtime-logs?start=1753362325074$26end=1753362625074)

2025-07-24T13:10:25.075Z
{"resource":{"attributes":{"deployment.environment.name":"bedrock-agentcore:default","aws.local.service":"mcp_server_ac.DEFAULT","service.name":"mcp_server_ac.DEFAULT","cloud.region":"us-east-1","aws.log.stream.names":"runtime-logs","telemetry.sdk.name":"opentelemetry","aws.service.type":"gen_ai_agent","telemetry.sdk.language":"python","cloud.provider":"aws","cloud.resource_id":"arn:aws:bedrock-agentcore:us-east-1:536824385237:runtime/mcp_server_ac-4ZCTFo8gFK/runtime-endpoint/DEFAULT:DEFAULT","aws.log.group.names":"/aws/bedrock-agentcore/runtimes/mcp_server_ac-4ZCTFo8gFK-DEFAULT","telemetry.sdk.version":"1.33.1","cloud.platform":"aws_bedrock_agentcore","telemetry.auto.version":"0.10.0-aws"}},"scope":{"name":"mcp.server.transport_security"},"timeUnixNano":1753362625075924736,"observedTimeUnixNano":1753362625075993487,"severityNumber":13,"severityText":"WARN","body":"Missing Content-Type header in POST request","attributes":{"otelTraceSampled":true,"code.file.path":"/usr/local/lib/python3.12/site-packages/mcp/server/transport_security.py","code.function.name":"_validate_content_type","otelTraceID":"688230c185d7379b17fa204f6432d847","otelSpanID":"193e2aca79fab1e8","code.line.number":92,"otelServiceName":"mcp_server_ac.DEFAULT"},"flags":1,"traceId":"688230c185d7379b17fa204f6432d847","spanId":"193e2aca79fab1e8"}
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/runtime-logs?start=1753362325075$26end=1753362625075)

2025-07-24T13:10:27.074Z
{"resource":{"attributes":{"deployment.environment.name":"bedrock-agentcore:default","aws.local.service":"mcp_server_ac.DEFAULT","service.name":"mcp_server_ac.DEFAULT","cloud.region":"us-east-1","aws.log.stream.names":"runtime-logs","telemetry.sdk.name":"opentelemetry","aws.service.type":"gen_ai_agent","telemetry.sdk.language":"python","cloud.provider":"aws","cloud.resource_id":"arn:aws:bedrock-agentcore:us-east-1:536824385237:runtime/mcp_server_ac-4ZCTFo8gFK/runtime-endpoint/DEFAULT:DEFAULT","aws.log.group.names":"/aws/bedrock-agentcore/runtimes/mcp_server_ac-4ZCTFo8gFK-DEFAULT","telemetry.sdk.version":"1.33.1","cloud.platform":"aws_bedrock_agentcore","telemetry.auto.version":"0.10.0-aws"}},"scope":{"name":"mcp.server.streamable_http_manager"},"timeUnixNano":1753362627074878464,"observedTimeUnixNano":1753362627074951807,"severityNumber":9,"severityText":"INFO","body":"Created new transport with session ID: f0acec6071bb4a7a9b3beb88a1d471f3","attributes":{"otelTraceSampled":true,"code.file.path":"/usr/local/lib/python3.12/site-packages/mcp/server/streamable_http_manager.py","code.function.name":"_handle_stateful_request","otelTraceID":"688230c3d2bd5c5d2d84507ae1eef2e3","otelSpanID":"613920104f7514be","code.line.number":233,"otelServiceName":"mcp_server_ac.DEFAULT"},"flags":1,"traceId":"688230c3d2bd5c5d2d84507ae1eef2e3","spanId":"613920104f7514be"}
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/runtime-logs?start=1753362327074$26end=1753362627074)

2025-07-24T13:10:27.076Z
{"resource":{"attributes":{"deployment.environment.name":"bedrock-agentcore:default","aws.local.service":"mcp_server_ac.DEFAULT","service.name":"mcp_server_ac.DEFAULT","cloud.region":"us-east-1","aws.log.stream.names":"runtime-logs","telemetry.sdk.name":"opentelemetry","aws.service.type":"gen_ai_agent","telemetry.sdk.language":"python","cloud.provider":"aws","cloud.resource_id":"arn:aws:bedrock-agentcore:us-east-1:536824385237:runtime/mcp_server_ac-4ZCTFo8gFK/runtime-endpoint/DEFAULT:DEFAULT","aws.log.group.names":"/aws/bedrock-agentcore/runtimes/mcp_server_ac-4ZCTFo8gFK-DEFAULT","telemetry.sdk.version":"1.33.1","cloud.platform":"aws_bedrock_agentcore","telemetry.auto.version":"0.10.0-aws"}},"scope":{"name":"mcp.server.transport_security"},"timeUnixNano":1753362627076593920,"observedTimeUnixNano":1753362627076658993,"severityNumber":13,"severityText":"WARN","body":"Missing Content-Type header in POST request","attributes":{"otelTraceSampled":true,"code.file.path":"/usr/local/lib/python3.12/site-packages/mcp/server/transport_security.py","code.function.name":"_validate_content_type","otelTraceID":"688230c3d2bd5c5d2d84507ae1eef2e3","otelSpanID":"613920104f7514be","code.line.number":92,"otelServiceName":"mcp_server_ac.DEFAULT"},"flags":1,"traceId":"688230c3d2bd5c5d2d84507ae1eef2e3","spanId":"613920104f7514be"}
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/runtime-logs?start=1753362327076$26end=1753362627076)

2025-07-24T13:10:27.074Z
INFO: 127.0.0.1:37894 - "POST /mcp/ HTTP/1.1" 307 Temporary Redirect
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362327074$26end=1753362627074)

2025-07-24T13:10:27.074Z
2025-07-24 13:10:27,074 - mcp.server.streamable_http_manager - INFO - Created new transport with session ID: f0acec6071bb4a7a9b3beb88a1d471f3
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362327074$26end=1753362627074)

2025-07-24T13:10:27.076Z
2025-07-24 13:10:27,076 - mcp.server.transport_security - WARNING - Missing Content-Type header in POST request
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362327076$26end=1753362627076)

2025-07-24T13:10:27.077Z
INFO: 127.0.0.1:37894 - "POST /mcp HTTP/1.1" 400 Bad Request
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362327077$26end=1753362627077)

2025-07-24T13:10:29.075Z
INFO: 127.0.0.1:37908 - "POST /mcp/ HTTP/1.1" 307 Temporary Redirect
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362329075$26end=1753362629075)

2025-07-24T13:10:29.076Z
2025-07-24 13:10:29,076 - mcp.server.streamable_http_manager - INFO - Created new transport with session ID: 4eccfc668dae450d97e9c61960f7f6d6
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362329076$26end=1753362629076)

2025-07-24T13:10:29.078Z
2025-07-24 13:10:29,077 - mcp.server.transport_security - WARNING - Missing Content-Type header in POST request
[Link ](https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logsV2:log-groups/log-group/%2Faws%2Fbedrock-agentcore%2Fruntimes%2Fmcp_server_ac-4ZCTFo8gFK-DEFAULT/log-events/2025%2F07%2F24%2F%5Bruntime-logs%5D9768e23b-c8e9-41cc-b2b7-b4fea8cc643e?start=1753362329078$26end=1753362629078)

2025-07-24T13:10:29.078Z
INFO: 127.0.0.1:37908 - "POST /mcp HTTP/1.1" 400 Bad Request
```

**To Reproduce**
followed exact steps as example to setup a mcp server

**Expected behavior**
tool list to be fetched

**Screenshots**
If applicable, add screenshots to help explain your problem.

**! Additional context !**
- Sagemaker Studio Kernel used
- Instance used
- commit link to the workshop if you're not using the latest

Start with the MCP server sample and reproduce the documented setup in the SageMaker Studio Kernel, focusing on requests to the /mcp entry point. Compare the request behavior with the expected tool-list flow and the logged redirect, missing Content-Type warning, and 400 response; done means the tool list is fetched successfully.

Written by the indexing model from the issue text.