[Bug] Make `ResponseValidator` fail closed when it detects hedging/tool-less answers

[shaaravraghu]

Description

ResponseValidator claims to "catch common hallucination signals and enforce quality gates", but hedging matches only produce a warning log and the response is still returned to the user. In an HR/Finance assistant, this means unreliable tool-less answers can still be delivered after being flagged internally.

Component

• Chat Connector
• Flowise Flow
• Demo MCP Server
• Documentation
• Other

Steps to Reproduce

1. Call ResponseValidator.validate("I think you probably have 12 days left").
2. Observe that the validator logs a warning but still returns the original text.

Expected Behavior

Once the validator identifies strong hallucination/hedging indicators, it should either:

1. replace the response with the safe fallback, or
2. mark the answer for a retry/tool-only recovery path.

Actual Behavior

The validator passes the risky answer through unchanged.

Environment

• OS: Any
• Python version: Source analysis
• Docker version: N/A
• Chat platform: Any
• Flowise version: Any

Logs

Relevant code paths:
- chat-connector/app/response_validator.py:29-74

Additional Context

This is particularly visible because the class docstring promises stronger protection than the implementation actually provides.

Evidence

• chat-connector/app/response_validator.py

Suggested fix

• Convert hedging detection into a fail-closed behavior for tool-grounded intents
• Consider returning the existing safe fallback or triggering a second-pass tool retry