feat(tool-rails): add support for tool input rails and validation

[Pouyanpi]

PR Description

Tool Input Rails Implementation

This PR implements comprehensive tool input rails functionality to validate and secure tool messages before they are processed by the LLM.

Key Changes:

• Added UserToolMessages event processing with grouped tool message handling
• Fixed message-to-event conversion for proper tool message support in conversation flows
• Enhanced passthrough mode to preserve full conversation context including tool calls
• Implemented tool input rail flows supporting validation, safety checks, and sanitization
• Comprehensive test coverage for all tool input rails scenarios

Benefits:

• Enables validation and filtering of potentially dangerous tool outputs
• Provides sanitization capabilities for sensitive information in tool responses
• Maintains conversation context integrity during tool interactions
• Supports configurable tool input validation pipelines

[Copilot]

Pull Request Overview

This PR implements comprehensive tool input rails functionality to validate and secure tool messages before they are processed by the LLM.

• Added UserToolMessages event processing with grouped tool message handling
• Fixed message-to-event conversion for proper tool message support in conversation flows
• Enhanced passthrough mode to preserve full conversation context including tool calls

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/test_tool_calls_event_extraction.py	Updates test for event name change from BotToolCall to BotToolCalls
tests/test_tool_calling_passthrough_only.py	Updates test assertions and comments for event name change
tests/test_input_tool_rails.py	Comprehensive test suite for tool input rails functionality
tests/test_bot_tool_call_events.py	Updates comments to reflect event name change
tests/runnable_rails/test_tool_calling.py	Updates test comment for event name change
tests/runnable_rails/test_runnable_rails.py	Updates test assertion for improved passthrough mode behavior
tests/input_tool_rails_actions.py	Test utility actions for tool input validation, safety checking, and sanitization
nemoguardrails/rails/llm/llmrails.py	Core implementation for message-to-event conversion with tool message support
nemoguardrails/rails/llm/llm_flows.co	Flow definitions for tool input rails processing
nemoguardrails/integrations/langchain/runnable_rails.py	Enhanced message conversion with tool call support
nemoguardrails/actions/llm/utils.py	Updated tool call extraction functions for new event name
nemoguardrails/actions/llm/generation.py	Enhanced passthrough mode to preserve tool message context

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Pull Request Overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[tgasser-nv]

Looks good, approving. Please address feedback before merging. This is another >1k line PR which should be broken into smaller stacked PRs to review.

Please also run local integration-tests to make a few tool-calls to production LLMs to check this works before merging. There are also some Github CI tests failing, could you take a look before merging?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 83.67347% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...uardrails/integrations/langchain/runnable_rails.py	33.33%	6 Missing ⚠️
nemoguardrails/actions/llm/generation.py	90.00%	1 Missing ⚠️
nemoguardrails/rails/llm/llmrails.py	95.23%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!