---
title: "Lucent API Reference"
description: "Reference documentation for XI Lucent's HTTP REST API, MCP tools, and CLI."
published: 2026-05-14T12:11:10.611639+00:00
updated: 2026-05-14T12:11:10.611639+00:00
tags: ["api", "lucent", "reference"]
url: https://xiobjects.com/docs/xio/lucent/api
source: XI Objects
---

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# Lucent API Reference

XI Lucent ships multiple control surfaces over the same `IKnowledgeEngine` core. Pick the one that fits your deployment.

- [REST API](/docs/xio/lucent/api/rest) — HTTP endpoints via `Xio.Lucent.Api`; mount into any ASP.NET Core host or use the ready-to-run `Xio.Lucent.Api.Host`
- [MCP Tools](/docs/xio/lucent/api/mcp) — Model Context Protocol tool definitions via `Xio.Lucent.Mcp`; lets LLM agents ingest and query directly
- [CLI Reference](/docs/xio/lucent/api/cli) — the `xio-lucent` dotnet tool for scripting and local exploration

The gRPC surface (`Xio.Lucent.Grpc`) exposes the same operations as the REST API with client-streaming ingestion and server-streaming retrieval. A `.proto` file ships in the NuGet package under `content/Protos/lucent.proto` for polyglot codegen.
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