# Tool Interface

> The defined contract through which an agent invokes external tools and receives their results.

Record: `lexicon:tool-interface`
Kind: constraint
Layer: [Correctness Core](https://banes-lab.com/records/layer/correctness-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lexicon-tool-interface

Listed in [Lexicon terms](https://banes-lab.com/api/records/lexicon.md), after [Schema/Ontology](https://banes-lab.com/records/lexicon/schema-ontology.md) and before [Training/Inference Separation](https://banes-lab.com/records/lexicon/training-inference-separation.md).

## Category

- [Model Architecture](https://banes-lab.com/records/lexicon-category/model-architecture.md)

## Required by

- [Agentic Architecture](https://banes-lab.com/records/architecture/agentic-architecture.md)

## Linked from

- [Model Architecture](https://banes-lab.com/ontology/principles/architecture-category-model-architecture.md)