MNPI Filter

The mnpi-filter policy is an output-phase blocker for material non-public information signals. It scans generated output text for configured detect_patterns or a small built-in default list and blocks the response when a phrase is found.

Configuration

pack:
  name: mnpi-filter
  version: "1.0.0"
  enabled: true

policies:
  chain:
    - mnpi-filter

policy:
  mnpi-filter:
    detect_patterns:
      - "earnings before announcement"
      - "merger not public"
      - "insider information"
      - "board decision"

Fields

Field	Type	Description	Default
detect_patterns	string[]	Case-insensitive phrases checked against generated output. If empty, the policy falls back to the built-in defaults below.	built-in list
action	block	The only accepted action; every match blocks.	block

Built-in defaults

If you omit detect_patterns, the gateway uses this default list:

• earnings before announcement
• merger not public
• insider information
• board decision
• not public

How it works

1. Output extraction: the gateway extracts assistant output text from the buffered response body.
2. Pattern scan: the gateway lowercases the text and checks for configured or built-in phrases.
3. Context details: the policy also records whether nearby stock-symbol context words such as earnings, merger, ipo, or acquisition appeared in the text.
4. Verdict: any phrase match blocks the output with reason_code = "mnpi.detected".

Important limitations

• This policy evaluates output text only.
• The policy does not support a configurable warn or redact mode today.
• The built-in defaults are intentionally small. Real deployments should add firm-specific phrases.

Valid examples

Default output block

pack:
  name: mnpi-defaults
  version: "1.0.0"
  enabled: true

policies:
  chain:
    - mnpi-filter

policy:
  mnpi-filter: {}

Add firm-specific phrases

pack:
  name: investment-banking-guardrail
  version: "1.0.0"
  enabled: true

policies:
  chain:
    - mnpi-filter
    - financial-compliance

policy:
  mnpi-filter:
    detect_patterns:
      - "earnings before announcement"
      - "pending acquisition"
      - "guidance revision not public"
      - "board decision"
      - "deal valuation confidential"

Best practices

• Replace or extend the defaults with language used by your legal and compliance teams.
• Pair with financial-compliance for broader finance-output controls.
• Review blocked events regularly and refine the phrase list based on actual false positives and misses.

Next steps

• Financial Compliance — Finance-specific rewrite and block controls
• Human Oversight — Escalate risky outputs elsewhere in the chain
• Audit Logger — Mark audit logging as active in the policy decision stream
• Trail and Audit Evidence — Inspect and verify persisted decision evidence
• PII Detector — Sanitize sensitive identifiers in related workflows