T3-R2 in five minutes
Hosted APIs usually separate system, user, and tool messages. Confirm the current API.
The system message is not a secret from a determined user. Do not put a key there.
Tool results should be marked as tool results.
Order matters because the model reads the sequence.
Record which role said each line in the trace.
A trace that flattens every role into one paragraph hides whether the tool or the model spoke. Keep the roles.
Sources and go deeper
- Anthropic, Building effective agents vendor last checked 2026-10
- Amazon Bedrock overview vendor last checked 2026-10
- Prompt engineering — Wikipedia wikipedia last checked 2026-10