ModelRefs / Tool Approval Gateway — Tool Pattern
Tool Approval Gateway — Tool Pattern
Insert a human-in-the-loop gate that pauses tool execution for sensitive operations until an approver signs off. Decisions are logged.
Overview
Mark tools or argument patterns as 'requires approval'. The runtime pauses execution, presents the call to a reviewer, and resumes only after explicit approval. Decisions are logged.
When to use it: You need a hard gate before destructive or high-impact tool calls.
Pattern details
| Pattern class | safety |
|---|---|
| Difficulty | intermediate |
| Invocation mode | asynchronous |
| Also known as | hitl tool gate, approval gate |
| Last reviewed | 2026-06-07 |
Known failure modes
- Approver bottleneck — Reviewers cannot keep up with volume. Mitigation: Tune the policy; add reviewers; auto-approve safe argument ranges.
When not to use it
- Letting model output bypass approval by re-phrasing the call.
Continue your research
Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to Tool Approval Gateway — Tool Pattern.
Frequently asked questions
When should I use the Tool Approval Gateway tool pattern?
You need a hard gate before destructive or high-impact tool calls.
What are common failure modes of Tool Approval Gateway?
Approver bottleneck
Is Tool Approval Gateway production-ready?
Yes when paired with the safety controls and observability hooks documented on the pattern page.