Bounded Bedrock assistant

Example user request

"Add a private question box that gives an operator one concise answer from the platform-configured model."

Fit and template

Start from scripts/artifacts/templates/python-api, add pinned and tested compatible boto3/botocore versions to requirements.txt, keep a private page at /, and expose one server-side POST /_artifact/api/chat path. This is not an AgentCore runner or autonomous assistant.

Contract decisions

• The browser posts to ./_artifact/api/chat; it never holds credentials or calls Bedrock directly.
• Require the platform viewer dependency, accept one message of at most 4,000 characters, and make exactly one Converse operation per valid turn.
• Read the model from PLATFORM_ARTIFACT_BEDROCK_MODEL_ID and use the injected platform_artifact_inference.BedrockInference helper. Topline supplies the production inference role and region; customers do not enable AWS models. Do not add an API key, caller-supplied model, memory, tools, retrieval, streaming, transcript, worker, or schedule.
• Cap output at 512 tokens and return whether stopReason was max_tokens so the UI can say the answer reached its limit.
• Return 503 when model configuration or the bounded provider call is unavailable. Do not expose raw provider errors.

Bounded invocation

Keep SDK timeouts and retry work inside the artifact's request deadline (30 seconds unless resources.timeoutSeconds raises it):

from botocore.config import Config
from platform_artifact_inference import BedrockInference

client = BedrockInference(
    config=Config(
        connect_timeout=2,
        read_timeout=10,
        retries={"total_max_attempts": 1, "mode": "standard"},
    ),
)
response = client.converse(
    modelId=os.environ["PLATFORM_ARTIFACT_BEDROCK_MODEL_ID"],
    messages=[{"role": "user", "content": [{"text": question}]}],
    inferenceConfig={"maxTokens": 512},
)
result = {
    "answer": response["output"]["message"]["content"][0]["text"],
    "truncated": response.get("stopReason") == "max_tokens",
}

The helper assumes the model-scoped Topline production role and refreshes its in-memory credentials five minutes before expiry. It leaves customer data/secret clients on their existing workload identity. Missing or denied inference configuration fails closed; there is no customer-account Bedrock fallback. Include STS and Bedrock time in the request deadline and return the safe unavailable response on provider failures. Do not copy credentials into environment variables, source, logs, or chat.

Validation and controls

• Replace the template's /_artifact/api/example implementation and src/check.py assertions; inherited checks do not validate chat.
• Stub the injected inference module for local tests. Test POST only, viewer required, invalid/no-session makes zero calls, valid makes exactly one model operation, message bounds, missing model or inference role returns 503, bounded provider failures, max_tokens returns truncated: true, and no raw error leaks.
• Verify browser code uses the relative route and visibly distinguishes unavailable and truncated answers.
• Run structured Python checks, node scripts/artifacts/validate-local --dir <appDir>, source sync, draft deploy, rendered smoke, and validation.

Limitations and graduation boundary

This is one bounded completion. Multi-turn memory, retrieval, tools, streaming, model selection, cross-user history, or autonomous execution requires explicit privacy, cost, and platform-service review.