> ## Documentation Index
> Fetch the complete documentation index at: https://productos.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

> The six most load-bearing terms in the ProductOS docs, with one-line definitions and a link to the full glossary on productos.dev.

The full ProductOS glossary lives at [productos.dev/glossary](https://productos.dev/glossary). It covers 30+ terms across product management and AI, each with a definition, comparisons, and FAQs. The six below carry the most weight in these docs.

| Term                                                                                                | Definition                                                                                                                                                                          |
| --------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [AI agent](https://productos.dev/glossary/ai-agent)                                                 | A software system that uses a language model to plan and execute multi-step tasks toward a goal, calling tools, checking results, and adjusting without step-by-step instructions.  |
| [Product requirements document (PRD)](https://productos.dev/glossary/product-requirements-document) | A structured specification that defines what a product should do and why: the problem, target user, scope, user stories, and acceptance criteria that guide design and engineering. |
| [Model Context Protocol (MCP)](https://productos.dev/glossary/model-context-protocol)               | An open standard that connects AI models to external tools and data sources through one consistent interface, with no custom integration code per client.                           |
| [Code ownership](https://productos.dev/glossary/code-ownership)                                     | The right to fully export, host, modify, and keep the source code a platform generates for you, so your product exists independently of any vendor or subscription.                 |
| [Bring your own keys (BYOK)](https://productos.dev/glossary/bring-your-own-keys)                    | A usage model that routes an AI tool's requests through your own provider API keys, so usage bills to your account and data flows under your own provider agreement.                |
| [Design system](https://productos.dev/glossary/design-system)                                       | A reusable library of components, design tokens, and usage rules that keeps a product's interface consistent as it grows across screens, features, and teams.                       |

Where these terms live in the docs:

* Agents and the pipeline: [Agents overview](/agents/overview)
* PRDs in practice: [The PRD stage](/build/prd)
* MCP in practice: [MCP integration](/integrations/mcp)
* Code ownership in practice: [Code ownership](/platform/code-ownership)
* BYOK in practice: [BYOK and models](/platform/byok-and-models)
* Design systems in practice: [Brand and design systems](/design/brand-and-design-systems)