Canonical: https://composio.dev/glossary
Markdown: https://composio.dev/glossary.md

# Agent integration glossary

Definitions of MCP gateways, tools, authentication, and credential custody, with technical references and implementation guides.

## [MCP gateway](https://composio.dev/glossary/mcp-gateway)

An MCP gateway is an intermediary between MCP clients and MCP servers that routes requests and centralizes access controls.

[Read as Markdown](https://composio.dev/glossary/mcp-gateway.md)

## [Model Context Protocol](https://composio.dev/glossary/model-context-protocol)

Model Context Protocol, or MCP, is an open protocol that lets AI applications connect to servers exposing tools, resources, and prompts.

[Read as Markdown](https://composio.dev/glossary/model-context-protocol.md)

## [Toolkit](https://composio.dev/glossary/toolkit)

A toolkit is a collection of related tools for one external service, such as GitHub, Gmail, or Slack.

[Read as Markdown](https://composio.dev/glossary/toolkit.md)

## [Tool](https://composio.dev/glossary/tool)

A tool is an individual action an agent can request, described by a name and schemas for its inputs and outputs.

[Read as Markdown](https://composio.dev/glossary/tool.md)

## [Auth config](https://composio.dev/glossary/auth-config)

An auth config is a toolkit's authentication blueprint, defining its authentication method, scopes, and application credentials.

[Read as Markdown](https://composio.dev/glossary/auth-config.md)

## [Connected account](https://composio.dev/glossary/connected-account)

A connected account is a stored set of provider credentials linked to a user and toolkit, created when the user authenticates with that service.

[Read as Markdown](https://composio.dev/glossary/connected-account.md)

## [Session](https://composio.dev/glossary/session)

A Composio session is a runtime context that ties a user identity to the tools, authentication configuration, and connected accounts available to an agent.

[Read as Markdown](https://composio.dev/glossary/session.md)

## [Token custody](https://composio.dev/glossary/token-custody)

Token custody describes which system stores provider credentials and which system retrieves and injects them into authenticated requests.

[Read as Markdown](https://composio.dev/glossary/token-custody.md)

Reviewed: 2026-10-29
Next review: 2027-01-29
Owner: Brendan O'Leary / Developer Marketing