> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/guardrails/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/guardrails/_mcp/server.

# Colang 2.0 Language Reference

> Reference documentation for Colang 2.0 syntax, events, actions, flows, variables, and the standard library.

#### [Introduction](/configure-guardrails/colang/colang-2/language-reference/introduction)

Understand Colang 2.0 concepts and basic syntax.

#### [Event Generation and Matching](/configure-guardrails/colang/colang-2/language-reference/event-generation-and-matching)

Learn how Colang generates and matches events.

#### [Working with Actions](/configure-guardrails/colang/colang-2/language-reference/working-with-actions)

Use actions and action events in Colang.

#### [Defining Flows](/configure-guardrails/colang/colang-2/language-reference/defining-flows)

Define, start, await, and compose flows.

#### [Working with Variables and Expressions](/configure-guardrails/colang/colang-2/language-reference/working-with-variables-and-expressions)

Use variables and expressions in Colang.

#### [Flow Control](/configure-guardrails/colang/colang-2/language-reference/flow-control)

Use branching, loops, and return or abort statements.

#### [Colang Standard Library (CSL)](/configure-guardrails/colang/colang-2/language-reference/the-standard-library)

Use the Colang Standard Library modules.

#### [Make Use of LLMs](/configure-guardrails/colang/colang-2/language-reference/make-use-of-llms)

Configure and use LLM-related features.

#### [More on Flows](/configure-guardrails/colang/colang-2/language-reference/more-on-flows)

Explore advanced flow behavior and conflict resolution.

#### [Python Actions](/configure-guardrails/colang/colang-2/language-reference/python-actions)

Call custom Python actions from Colang.

#### [Development and Debugging](/configure-guardrails/colang/colang-2/language-reference/development-and-debugging)

Debug Colang flows and inspect runtime state.

This chapter is a comprehensive introduction to Colang, explaining all important concepts in a bottom up approach.

* [Introduction](/configure-guardrails/colang/colang-2/language-reference/introduction#reference_introduction)
* [Event Generation & Matching](/configure-guardrails/colang/colang-2/language-reference/event-generation-and-matching#event-generation-and-matching)
* [Working with Actions](/configure-guardrails/colang/colang-2/language-reference/working-with-actions#working-with-actions)
* [Defining Flows](/configure-guardrails/colang/colang-2/language-reference/defining-flows#defining-flows)
* [Working with Variables & Expressions](/configure-guardrails/colang/colang-2/language-reference/working-with-variables-and-expressions#working-with-variables-and-expressions)
* [Flow control](/configure-guardrails/colang/colang-2/language-reference/flow-control#flow-control)
* [Colang Standard Library (CSL)](/configure-guardrails/colang/colang-2/language-reference/the-standard-library#the-standard-library)
* [Make use of Large Language Models (LLM)](/configure-guardrails/colang/colang-2/language-reference/make-use-of-llms#make-use-of-llms)
* [More on Flows](/configure-guardrails/colang/colang-2/language-reference/more-on-flows#more-on-flows)
* [Python Actions](/configure-guardrails/colang/colang-2/language-reference/python-actions#python-actions)
* [Development and Debugging](/configure-guardrails/colang/colang-2/language-reference/development-and-debugging#development-and-debugging)