type: "Stack layer"
title: "Discovery and current-context retrieval"
description: "Finding that a capability exists, and selecting a small candidate set at inference time."
tags: [stack, discovery, retrieval]
generated: { by: human:crpage, at: 2026-07-09T09:44:00Z }
status: stable

Role in the stack

Discovery should be a first-class runtime capability, not a side effect of stuffing all tools into one prompt. Discovery finds that a capability exists (catalogues, OpenAPI docs, A2A Agent Cards, protocol registries, and content/skills registries such as Context Hub); retrieval selects a small candidate set from a large inventory at inference time.

Evidence

Gorilla + a retriever and ToolLLM + a neural retriever both address the scaling problem when the tool set is too large for naïve prompting. Retrieval narrows the search space and improves freshness — necessary but insufficient for trustworthy action.

Relates to: UK API Catalogue, Contracts and interfaces.

Terms

Glossary terms used here: Agent Card.