Documentation: explain why `BedrockResponse.is_json` always returns `True` regardless of Content-Type

[T90REAL]

Expected Behaviour

resp_text.is_json() returns False because the content type is not JSON.

Current Behaviour

Both calls return True; is_json ignores content_type.

Code snippet

from aws_lambda_powertools.event_handler.api_gateway import BedrockResponse

resp_json = BedrockResponse(body={"ok": True}, content_type="application/json")
resp_text = BedrockResponse(body="plain", content_type="text/plain")

print(resp_json.is_json())
print(resp_text.is_json())

True
True

Possible Solution

Response.is_json() in the same file correctly looks at the Content-Type. BedrockResponse.is_json() should follow the same logic (checking for application/json or variants) instead of returning True unconditionally.

Steps to Reproduce

Run the repro script.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.12

Packaging format used

PyPi

Debugging logs

[dreamorosi]

Hi @T90REAL, thanks for opening this issue.

My understanding is that: while it's true that the method ignores the content type and is also a bit confusing, the current behavior is intended.

Based on this section of the Lambda + Bedrock integration, the only content type supported is text:

responseBody – Contains an object that defines the response from execution of the function. The key is the content type (currently only TEXT is supported) and the value is an object containing the body of the response.

Because of this, in practice setting the content type to anything other than text, including application/json is useless.

With this in mind, having the is_json method is also kind of useless and confusing, however it's there because we added the Bedrock Agents feature on top of the REST one, and that method was already there.

I'll leave the issue open so that someone from @aws-powertools/python can provide additional details to complement my answer, however I think this is not a bug but rather should be a documentation improvement.