fix(library)!: make manifest-declared flows portable across Colang versions

[Pouyanpi]

Description

Several packaged library flows either fail to parse under Colang 2 or invoke
action names the runtime cannot resolve. This PR normalizes vendor action
names, repairs the broken Colang 2 flows, adds the missing GCP Colang 1 variant,
and adds a cross-dialect regression gate. Parameterized Colang 2 flows remain
exempt from Colang 1 presence.

It also fixes blocked retrieval rails that re-enter retrieval instead of
terminating, preserves GCP's action-owned fail-closed verdict, and covers
context-bloat allow, block, and transform outcomes.

Compatibility: custom Colang 1 flows using the old space-separated Cleanlab,
Fiddler, or GCP action names must switch to their snake_case names. users enabling the shipped rail flows are unaffected because the bundled flows are updated together.

Impact

• Built-in manifest-declared rails can load and invoke their actions under both
  packaged Colang dialects instead of failing on invalid syntax or unresolved
  names.
• The gate detects future drift among manifest action references, flow bodies,
  and registered action names during tests rather than at user runtime.
• ActiveFence and GCP retain backend-neutral action-owned verdicts while their
  Colang flows remain responsible only for response presentation.
• GCP moderation remains fail-closed even when detailed violation metadata is
  unavailable.
• No configuration schema or manifest API is added in this layer.

Stack

Layer	Branch	Base	PR
Stack 3	pouyanpi/rail-library-stack-3-manifest-contract	develop	#2157
Stack 4	pouyanpi/rail-library-stack-4-builtins	Stack 3	#2181
Stack 4b	pouyanpi/rail-library-stack-4b-flow-gate	Stack 4	#2185
Stack 5	pouyanpi/rail-library-stack-5-lazy-actions	Stack 4b	#2186

Related Issue(s)

• Fixes #
• Internal tracking: NGUARD-855
• Issue assignee: @

Verification

• see https://github.com/NVIDIA-NeMo/Guardrails/actions/runs/29579138642

AI Assistance

• No AI tools were used.
• AI tools were used; a human reviewed and can explain every change (tool: Codex).

Codex assisted with implementation analysis, validation, stack restructuring,
and this draft. Check the disclosure box after human review.

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.
• I've noted any verification beyond CI and any checks I couldn't run.
• I did not update generated changelog files manually.
• I addressed all CodeRabbit, Greptile, and other review comments, or replied with why no change is needed.
• @mentions of the person or team responsible for reviewing proposed changes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[greptile-apps]

Greptile Summary

This PR normalizes vendor action names to snake_case, repairs Colang 2 flow files that used invalid syntax (lowercase await calls treated as flow references, old space-separated action names), adds the missing GCP Colang 1 flow file, fixes retrieval rails that re-entered retrieval on block, and adds a cross-dialect regression gate (test_library_flow_files.py).

• Action renames: call cleanlab api → call_cleanlab_api, call gcpnlp api → call_gcpnlp_api, three Fiddler names, and call activefence api / call gcpnlp api in filters.py are normalized to CallActivefenceApiAction / CallGcpnlpApiAction (the PascalCase form the Colang 2 runtime emits on ActionFinished).
• Retrieval block fix: Colang 1 retrieval flows for gliner, polygraf, privateai, sensitive_data_detection, and context_bloat_detection now use create event BotMessage(text=...) + $skip_output_rails = True instead of a bot X directive (which caused the retrieval pipeline to re-trigger), while Colang 2 already used abort and is unaffected.
• New tests: test_library_flow_files.py enforces parse validity, cross-dialect flow presence, and action-resolver consistency at CI time.

Confidence Score: 4/5

Safe to merge once the Colang 1 retrieval flow files that access $config.bot_messages without a local message definition are addressed; otherwise those retrieval rails will throw a KeyError at runtime for configurations that do not co-load a file defining the required bot message.

The action name normalizations, GCP dialect additions, and Colang 2 fixes are all correct and well-tested. The retrieval re-entry fix is sound for the context_bloat case where the message is defined locally. For gliner, polygraf, privateai, and sensitive_data_detection the same pattern reads a bot message key not defined in the respective flows.v1.co files, so the fix works only if the user config happens to load another library that defines the key.

nemoguardrails/library/gliner/flows.v1.co, nemoguardrails/library/polygraf/flows.v1.co, nemoguardrails/library/privateai/flows.v1.co, and nemoguardrails/library/sensitive_data_detection/flows.v1.co — each references a bot message key not defined locally.

Important Files Changed

Filename	Overview
nemoguardrails/library/sensitive_data_detection/flows.v1.co	Retrieval block now uses $config.bot_messages["inform answer unknown"][0]; this key is NOT defined in this file and must come from user config or another loaded library.
nemoguardrails/library/gliner/flows.v1.co	Retrieval block changed to use $config.bot_messages["refuse to respond"][0] + create event BotMessage, but "refuse to respond" is not defined in this file.
nemoguardrails/library/gcp_moderate_text/flows.co	Converted from Colang 1 to Colang 2 (flow / await CallGcpnlpApiAction / abort); underscore in abusive_or_harmful flow name matches defined bot flow.
nemoguardrails/library/gcp_moderate_text/flows.v1.co	New file: Colang 1 equivalent of the GCP moderation flows using call_gcpnlp_api and stop.
nemoguardrails/llm/filters.py	Replaces space-separated old action names with PascalCase forms the Colang 2 runtime emits in ActionFinished events.
nemoguardrails/library/regex/flows.co	Renames DetectRegexMatchAction to DetectRegexPatternAction, matching the registered action name detect_regex_pattern.
nemoguardrails/library/autoalign/flows.co	Fixes the only remaining lowercase action invocation: autoalign_factcheck_output_api to AutoalignFactcheckOutputApiAction.
tests/rails/llm/test_library_flow_files.py	New regression gate: parses flow files in both dialects, checks declared flow names, flags lowercase action invocations, and verifies action resolver consistency.
tests/test_runtime_flow_gate_equivalence.py	Extends equivalence test: adds retrieval RailSpecs, context_bloat cases, GCP detailed-moderation block cases, and injection-detection parametrized test.
nemoguardrails/library/injection_detection/flows.co	Colang 2 rewrite with correct $ prefixes, $system.config, elif, readable detection joins, and abort at correct indent level.
nemoguardrails/library/context_bloat_detection/flows.v1.co	Retrieval block uses direct BotMessage event to avoid re-entry; message key is defined in the same file.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Library Rail Loaded] --> B{Colang Dialect?}
    B -->|Colang 1 - flows.v1.co| C[execute snake_case_action]
    B -->|Colang 2 - flows.co| D[await CamelCaseAction]
    C --> E{Action resolves?}
    D --> F{Action resolves?}
    E -->|YES| G[Outcome: RailOutcome]
    E -->|NO - old space-separated name| H[Runtime Error]
    F -->|YES - dispatcher normalizes PascalCase| G
    F -->|NO - lowercase await is a flow ref| I[Silent wrong flow call]
    G --> J{is_blocked?}
    J -->|YES - Colang 2| K[bot X Y Z + abort]
    J -->|YES - Colang 1 INPUT/OUTPUT| L[bot X Y Z + stop]
    J -->|YES - Colang 1 RETRIEVAL| M[create event BotMessage + stop]
    J -->|NO - is_transform| N[Modify context variable]
    style H fill:#f66
    style I fill:#f66
    style M fill:#6f6

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[Library Rail Loaded] --> B{Colang Dialect?}
    B -->|Colang 1 - flows.v1.co| C[execute snake_case_action]
    B -->|Colang 2 - flows.co| D[await CamelCaseAction]
    C --> E{Action resolves?}
    D --> F{Action resolves?}
    E -->|YES| G[Outcome: RailOutcome]
    E -->|NO - old space-separated name| H[Runtime Error]
    F -->|YES - dispatcher normalizes PascalCase| G
    F -->|NO - lowercase await is a flow ref| I[Silent wrong flow call]
    G --> J{is_blocked?}
    J -->|YES - Colang 2| K[bot X Y Z + abort]
    J -->|YES - Colang 1 INPUT/OUTPUT| L[bot X Y Z + stop]
    J -->|YES - Colang 1 RETRIEVAL| M[create event BotMessage + stop]
    J -->|NO - is_transform| N[Modify context variable]
    style H fill:#f66
    style I fill:#f66
    style M fill:#6f6

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_{Reviews (5): Last reviewed commit: "fix(llm): filter vendor actions from Col..." | Re-trigger Greptile}

[Pouyanpi]

@greptileai any pending issues?

[greptile-apps]

All four inline review threads are resolved. The GCP flows.v1.co bot-message mismatch flagged in the summary ("in inappropriate content" vs "with inappropriate content") is also fixed — the current file uses "with" consistently throughout. Codecov is green.

The one loose end: at the end of the filters.py thread, I asked whether to persist a rule about Colang 2 ActionFinished events preserving PascalCase action names. No action needed on your side unless you want that rule saved — just let me know and I'll create it.

Everything else looks good to merge.