Require a specific action tool for a workflow

Goal

Use `tool_choice` to enforce a typed handoff when every request must produce a machine-consumable action proposal.

Steps

1. Define the action tool schema and set tool_choice={"type":"tool","name":"print_sentiment_scores"} for the constrained step. [source05]
2. Inspect the returned tool name and validate its input against the schema before accepting the proposal. [source05]
3. Add a fallback path with {"type":"auto"} when natural-language answers are allowed, and test irrelevant or adversarial prompts. [source05]

How to verify

With tool_choice forced, verify the returned block names print_sentiment_scores and still validate its fields; with auto mode, confirm a relevant text answer remains possible.

Troubleshooting

If an unrelated prompt produces a malformed action, reject it after schema validation and use the documented auto/fallback path; tool_choice enforces routing, not factual correctness.