> This page is for version v0.24.1. > For other versions, use one of these documentation indexes: > - Latest (default): https://docs.nvidia.com/nemo/guardrails/latest/llms.txt > - v0.24.1: https://docs.nvidia.com/nemo/guardrails/v0.24.1/llms.txt > - v0.24.0: https://docs.nvidia.com/nemo/guardrails/v0.24.0/llms.txt > - v0.23.0: https://docs.nvidia.com/nemo/guardrails/v0.23.0/llms.txt > - v0.22.0: https://docs.nvidia.com/nemo/guardrails/v0.22.0/llms.txt > 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. # Release Notes > Review new features, breaking changes, and fixed issues for each release. The following sections summarize and highlight the changes for the current release. For a complete record of changes in a release, refer to the [CHANGELOG.md](https://github.com/NVIDIA-NeMo/Guardrails/blob/develop/CHANGELOG.md) in the GitHub repository. --- ## 0.24.1 This patch release includes the following fixes: * Content-safety rails parse Nemotron 3.5 responses. * The server returns an overload response when IORails sheds a request through admission control. * Combined configurations load their `config.py` files. * Locust benchmarks correct concurrency measurements and support concurrency sweeps. For the complete list of changes, refer to the [v0.24.1 release](https://github.com/NVIDIA-NeMo/Guardrails/releases/tag/v0.24.1). --- ## 0.24.0 ### Key Features * Rail actions can use `RailOutcome` to return explicit allow, block, and transform decisions. Built-in rails now use declarative rail manifests to describe their configuration, actions, flows, supported surfaces, dependencies, and privacy behavior. For more information, refer to [Rail Outcomes](/configure-guardrails/actions/rail-outcomes) and [Rail Manifests](/reference/rail-manifests). * `IORails` adds `check()` and `check_async()` for running input and output rails without generating a model response. For non-streaming generation, it returns a structured `GenerationResponse` when you pass `GenerationOptions` or an options dictionary; when you omit generation options, it continues to return a role-content message dictionary. For more information, refer to [Check Messages](/run-guardrailed-inference/using-python-apis/check-messages), [Generation Options](/run-guardrailed-inference/using-python-apis/generation-options), and [Engine Feature Support](/reference/engine-feature-support). * `IORails` can run all built-in rail actions whose manifests do not require Colang-specific context variables. For the complete per-rail compatibility matrix, refer to [Rail Engine Support](/reference/rail-engine-support). * OpenAI-compatible model configurations can set per-model custom headers and query parameters with `parameters.default_headers` and `parameters.default_query`. The settings apply to both `IORails` and `LLMRails`. For more information, refer to [Custom HTTP Headers](/configure-guardrails/yaml-schema/model-configuration#custom-http-headers) and [Model-Level Query Parameters](/configure-guardrails/yaml-schema/model-configuration#model-level-query-parameters). * You can configure multiple self-check input and output rails, each with its own prompt and model selection. The rails run in configuration order and stop when a rail blocks the content. For more information, refer to [LLM Self-Check](/configure-guardrails/guardrail-catalog/self-check). * Actions and built-in integrations can use a canonical asynchronous HTTP boundary with shared client ownership, retries, metrics, tracing, and deterministic testing support. For more information, refer to [Outbound HTTP in Actions](/configure-guardrails/actions/outbound-http). * The Guardrails server adds `GET /v1/health` and `GET /healthz` liveness endpoints. The `/v1/checks` endpoint can also validate assistant messages against output rails without running generation. For more information, refer to [Run the Guardrails Server](/run-guardrailed-inference/using-fastapi-server/run-guardrails-server) and [Check Messages](/run-guardrailed-inference/using-python-apis/check-messages). * The guardrail catalog adds an F5 AI Guardrails integration for scanning input and output content. It supports configurable retry behavior and fail-open or fail-closed handling for provider errors. ### Breaking Changes * The `output_mapping` parameter and its implicit boolean and numeric mappings have been removed from `@action`. Passing `output_mapping` now raises `TypeError`. Return a `RailOutcome` from rail actions and inspect the outcome explicitly in the consuming flow. For migration examples, refer to [Rail Outcomes](/configure-guardrails/actions/rail-outcomes). * When you pass `GenerationOptions` or an options dictionary to non-streaming `IORails.generate()` or `IORails.generate_async()`, the methods return a `GenerationResponse`. When you omit generation options, they continue to return a role-content message dictionary. Their signatures now accept `prompt` as the first parameter. Pass message lists with the `messages=` keyword instead of as the first positional argument. * The `/v1/checks` endpoint no longer accepts inline configurations. Select a server-loaded configuration with `config_id`, or omit `config_id` to use the server default. * The Chat Completions endpoint now validates role-specific messages at the HTTP boundary. It rejects internal event messages, unexpected fields, unsupported audio requests, and invalid role or content combinations before loading a configuration or dispatching an action. For more information, refer to [Chat Completions](/run-guardrailed-inference/using-fastapi-server/chat-with-guardrailed-model). * Custom Colang 1.0 flows that call the previous space-separated Cleanlab, Fiddler, or GCP action names must use the corresponding snake\_case action names. The packaged flows have already been updated for both Colang 1.0 and Colang 2.x. * The `hf-classifier` installation extra has been removed, and its packages are no longer included in the `all` extra. Install `transformers` and `torch` directly to use the local classifier backend. For more information, refer to [HuggingFace Classifier Integration](/configure-guardrails/guardrail-catalog/third-party/hf-classifier). ### Enhancements * IORails generation logs include activated rails, model calls, timing, token usage, and provider metadata when requested. Streaming responses preserve usage metadata on the final chunk, and the default logger no longer emits verbose operational output. * Server responses use OpenAI-compatible error envelopes more consistently, preserve configured main-model fields when a request selects a model, and support `developer`, multimodal, tool, refusal, context, and function messages where the Chat Completions contract allows them. * The documentation site adds immutable, Git-ref-backed versions so you can switch between the latest documentation and stable release snapshots. ### Documentation and Behavior Fixes * IORails now distinguishes a policy block from a rail execution failure, and streaming output rails fail closed when an action fails. Content-safety response parsing errors are surfaced instead of being treated as successful checks. * The `/v1/checks` endpoint returns HTTP `422` when the requested rail types cannot run for the supplied messages instead of silently returning a passing result. * Reasoning-only non-streaming responses are handled correctly, reasoning content is inlined consistently for server responses, and model-level query parameters propagate through IORails requests. * Colang argument parsing now raises `ValueError` for an unbalanced closing bracket instead of accepting malformed input. ## Previous Releases * [0.23.0](/nemo/guardrails/v0.23.0/about-nemo-guardrails-library/release-notes) * [0.22.0](/nemo/guardrails/v0.22.0/about-nemo-guardrails-library/release-notes) * [0.21.0](https://archive.docs.nvidia.com/nemo/guardrails/0.21.0/index.html) * [0.20.0](https://archive.docs.nvidia.com/nemo/guardrails/0.20.0/index.html) * [0.19.0](https://archive.docs.nvidia.com/nemo/guardrails/0.19.0/index.html) * [0.18.0](https://archive.docs.nvidia.com/nemo/guardrails/0.18.0/index.html) * [0.17.0](https://archive.docs.nvidia.com/nemo/guardrails/0.17.0/index.html) * [0.16.0](https://archive.docs.nvidia.com/nemo/guardrails/0.16.0/index.html) * [0.15.0](https://archive.docs.nvidia.com/nemo/guardrails/0.15.0/index.html) * [0.14.1](https://archive.docs.nvidia.com/nemo/guardrails/0.14.1/index.html)