'charmap' codec can't encode character '\U0001f680' in position 4: character maps to <undefined>

[garretwilson]

Description

Running the bare AgentCore getting-started demo produces a Unicode error:

'charmap' codec can't encode character '\U0001f680' in position 4: character maps to

Steps to Reproduce

Exactly following [Get started with the AgentCore CLI]https://docs.aws.amazon.com/bedrock-agentcore/latest/devguide/runtime-get-started-cli.html):

1. npm install -g @aws/agentcore
2. agentcore create --name MyAgent --framework Strands --protocol HTTP --model-provider Bedrock --memory none
3. In MyAgent/model/load.py, change the model:

   return BedrockModel(model_id="global.amazon.nova-2-lite-v1:0")

4. cd MyAgent
5. agentcore dev
6. Enter a question; e.g. "What are the highlights of the uv package manager for Python?"

Expected Behavior

The model returns a response with no error.

Actual Behavior

The uv package manager for Python is an extremely fast, all-in-one tool that simplifies Python development by replacing multiple tools with a single, high-performance solution. Here are the key highlights of uv:

🚀 **Error: 'charmap' codec can't encode character '\U0001f680' in position 4: character maps to <undefined>

CLI Version

0.27.0

Operating System

Windows

Additional Context

Initial searches indicated this is related to Python. In any case, in an enterprise framework the first-steps demo should run without issue, across platforms.

From experience, I would guess that one or more layer is making assumptions about the system charset rather than being explicit about which charset is needed.

…

Looking at the console stack trace, the error seems to originate in: MyAgent\\app\\MyAgent\\.venv\\Lib\\site-packages\\bedrock_agentcore\\runtime\\app.py:_sync_stream_with_error_handling:945

[garretwilson]

UnicodeEncodeError: 'charmap' codec can't encode characters supports the idea that some layer is making assumptions about the error encoding.

Workaround

I made the error go away using the following in Git Bash:

export PYTHONIOENCODING=utf-8

You may be able to reproduce the error on a non-Windows system using:

PYTHONIOENCODING=windows-1252

See also Resolve Python UnicodeEncodeError ‘charmap’ codec: Explained.

In short, on the face of it, it looks like the Bedrock AgentCore Python library isn't bothering to specify the charset and assuming that it is UTF-8.

[garretwilson]

This is rough. Even invoking aws agent-toolkit list-available-skills on Windows produces:

aws: [ERROR]: 'charmap' codec can't encode character '\u2192' in position 249: character maps to

In this case export PYTHONIOENCODING=utf-8 doesn't work around it.