# NVIDIA NeMo Guardrails v0.24.0

Category: safety-research
Published: 2026-08-26T19:31:04Z
Source: [NVIDIA NeMo Guardrails releases](https://github.com/NVIDIA-NeMo/Guardrails/releases/tag/v0.24.0)
Agent usefulness: 89/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-11-03T00:18:04.096Z
Tags: guardrails, safety, nvidia

## Human Summary
NVIDIA NeMo Guardrails v0.24.0 expands IORails to support 59 action-backed input and output surfaces using a unified RailOutcome contract, manifests, and shared outbound HTTP, alongside several breaking API updates.

## Agent Summary
NeMo Guardrails 0.24.0 introduces RailOutcome (allow/block/transform), typed rail manifests, and a shared HTTP client. It includes breaking changes for custom actions (removal of output mapping), IORails parameter handling, /v1/checks configuration loading, Colang 1 action naming, and OpenAI chat completions payload validation.

## Body
NVIDIA NeMo Guardrails v0.24.0 substantially aligns IORails and LLMRails by allowing IORails to execute 59 of the 67 library action-backed surfaces. This unification is driven by three architectural additions: the engine-neutral RailOutcome contract (allow, block, transform), typed rail manifests for feature and privacy discovery, and a centralized outbound HTTP client managing pooling, retries, and metrics. The release adds F5 Guardrails integration, /v1/health endpoints, multiple namespaced self-check rails, and output-checking via /v1/checks. It also enforces fail-closed behavior on rail action streaming failures, distinguishes policy blocks from execution failures, and improves error mappings for OpenAI-compatible server interfaces. Significant breaking changes affect custom action decorators, IORails call signatures, dependency extras, /v1/checks invocation, and strict OpenAI message schema validation.

## Recommended actions
- Refactor custom actions to return an explicit RailOutcome and remove the deprecated @action(output mapping=...) argument.
- Update IORails generate/generate async calls to pass message lists using the keyword argument messages= instead of positionally, and handle GenerationResponse return types when generation options are provided.
- Install transformers and torch directly if utilizing local classifiers, as the hf-classifier extra has been removed.
- Update /v1/checks requests to reference a server-loaded config id or rely on the default configuration instead of passing inline configurations.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.