docs(guardrail-catalog): document running multiple self-check rails

[Pouyanpi]

Description

Add a "Running Multiple Self-Check Rails" section to the self-check guardrail reference. It covers the $variant= flow parameter: one flow per variant, a matching prompt task per variant, optional per-variant model routing via a model type that matches the variant name, and the fallback to the base self-check model type and then the main model. Notes that a missing variant prompt raises at config load and that a rail without $variant= uses the default prompt.

Related Issue(s)

#1874 #2175

Verification

fern passed locally

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Checklist

• I've read the CONTRIBUTING guidelines.
• This PR links to a triaged issue assigned to me.
• My PR title follows the project commit convention.
• I've updated the documentation if applicable.
• I've added tests if applicable.
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Summary by CodeRabbit

• Documentation
  • Added guidance for running multiple self-check input and output rails in a single configuration.
  • Documented variant-specific prompts, matching task names, and dedicated model routing.
  • Clarified configuration requirements, execution order, blocking behavior, and combining default and variant rails.

[github-actions]

Staged Fern docs preview: https://nvidia-preview-pr-2176.docs.buildwithfern.com/nemo/guardrails

[greptile-apps]

Greptile Summary

This PR adds a "Running Multiple Self-Check Rails" section to the self-check guardrail reference documentation, explaining how to run several independent self-check rails of the same kind (input or output) using the $variant=<name> flow parameter.

• Covers the three configuration pieces needed per variant: a flow entry in rails.{input,output}.flows, a matching prompts.yml task (using the self_check_{input,output} $variant=<name> format), and an optional model entry whose type equals the variant name.
• Accurately reflects the implementation in utils.py (get_self_check_llm fallback chain: variant model → base self-check model type → main model) and the config-load validation (_validate_self_check_rail_prompts) that raises on a missing prompt.

Confidence Score: 5/5

Documentation-only change; all YAML examples and behavioral claims were verified against the implementation and are accurate.

The new section correctly describes the variant flow parameter, the prompt task naming convention, the three-tier model fallback chain, and the config-load validation — each cross-checked against the corresponding source files. No code paths are modified.

No files require special attention.

Important Files Changed

Filename	Overview
docs/configure-rails/guardrail-catalog/self-check.mdx	Adds a 65-line 'Running Multiple Self-Check Rails' section; prose and YAML examples are factually consistent with the implementation in utils.py and config.py.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Output Rail triggered] --> B{Iterate flows in order}
    B --> C[Next variant flow]
    C --> D{Model type=variant defined?}
    D -- Yes --> E[Use variant model]
    D -- No --> F{Base self_check_output model defined?}
    F -- Yes --> G[Use base self-check model]
    F -- No --> H[Use main model]
    E --> I[Render prompt task]
    G --> I
    H --> I
    I --> J{LLM returns Yes blocked?}
    J -- Yes --> K[bot refuse to respond stop processing]
    J -- No --> L{More variant flows?}
    L -- Yes --> C
    L -- No --> M[Allow output]

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A[Output Rail triggered] --> B{Iterate flows in order}
    B --> C[Next variant flow]
    C --> D{Model type=variant defined?}
    D -- Yes --> E[Use variant model]
    D -- No --> F{Base self_check_output model defined?}
    F -- Yes --> G[Use base self-check model]
    F -- No --> H[Use main model]
    E --> I[Render prompt task]
    G --> I
    H --> I
    I --> J{LLM returns Yes blocked?}
    J -- Yes --> K[bot refuse to respond stop processing]
    J -- No --> L{More variant flows?}
    L -- Yes --> C
    L -- No --> M[Allow output]

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[coderabbitai]

📝 Walkthrough

Walkthrough

Adds documentation for configuring and running multiple self-check rails with named variants, matching prompts, optional dedicated models, execution ordering, blocking behavior, and default rails.

Changes

Self-check rail configuration

Layer / File(s)	Summary
Variant self-check rail guidance docs/configure-rails/guardrail-catalog/self-check.mdx	Documents $variant=<name> flows, required per-variant prompts, optional model routing through models[].type, execution order, stop-on-first-block behavior, and combining default and variant rails.

Estimated code review effort: 1 (Trivial) | ~2 minutes

🚥 Pre-merge checks | ✅ 6

✅ Passed checks (6 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: documenting how to run multiple self-check rails.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Test Results For Major Changes	✅ Passed	This is a small documentation-only change; the PR description also includes verification notes (“fern passed locally”).

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pouyanpi/docs-self-check-multiple-rails

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@docs/configure-rails/guardrail-catalog/self-check.mdx`:
- Around line 298-313: Expand the model-routing example around the model
definitions and fallback description to state the routing mode, supported model
modes, and applicable limitations or access requirements. Include the required
model type, routing mode, supported modes, and known limitations while
preserving the existing variant-specific and fallback routing behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📥 Commits

Reviewing files that changed from the base of the PR and between 450594a and 22f1248.

📒 Files selected for processing (1)

• docs/configure-rails/guardrail-catalog/self-check.mdx