n8n AI Agent Governance: OpenAI, pgvector Postgres & Gmail

Governed AI answers in n8n—webhook to OpenAI with Postgres/pgvector grounding, verification, and Gmail delivery

This n8n AI Agent Governance workflow accepts a webhook prompt, screens it for prompt-injection risk, grounds responses using a Postgres/pgvector knowledge base, verifies the output with a second OpenAI pass, optionally routes high-risk results for human approval, and then sends the verified answer to a recipient via Gmail.

What this workflow does

• Receives and normalizes webhook input (including optional requestedTools) into a tracked, governed request.
• Prompt-injection and secret-exfiltration screening blocks suspicious requests based on common risky patterns.
• Grounding with OpenAI embeddings + Postgres/pgvector: generates an embedding for the prompt, retrieves similar evidence from a knowledge_base, and stops if results don’t meet the grounding threshold.
• Policy-bound OpenAI chat prompting requiring citations of retrieved sources and enforcing a tool allowlisting gateway with risk tiering and optional human approval.
• Independent verification using a second OpenAI verifier to check grounding, unsupported claims, policy violations, and leakage—retrying with repair instructions up to the configured limit if verification fails.
• Token budgeting, risk scoring, and audit logging: enforces a token budget, classifies risk, routes high-risk outputs to a human approval queue, and writes an audit record to Postgres.
• Delivers the final verified response via Gmail to a configured recipient.

Use cases

• Customer-support or internal assistants that must stay grounded in a curated knowledge base.
• SaaS operators needing safer LLM automation with audit trails and controlled tool usage.
• Teams deploying n8n AI agents that require verification and optional human approval for higher-risk answers.

Technical details

• Integrations/nodes: webhook, OpenAI (chat + embeddings + verifier), postgres, pgvector (via Postgres knowledge base), gmail, if, code, sticky note.