Tool Calling (Deep Workflow)

Tool calling is contract design between a probabilistic planner (the model) and deterministic systems. Failures are usually schema, permissions, or ambiguity—not the LLM “being dumb.”

When to Offer This Workflow

Trigger conditions:

• Designing OpenAI/Anthropic-style functions, MCP tools, or internal JSON tool protocols
• Debugging wrong arguments, hallucinated parameters, or unsafe side effects
• Building agents with many tools—selection and routing problems

Initial offer:

Use six stages: (1) define tool surface, (2) schema & validation, (3) authz & safety, (4) execution semantics, (5) errors & observability, (6) evaluation & regression. Confirm side-effect class (read-only vs write).

Stage 1: Define Tool Surface