Signal/TERAX.md

Signal — Terax AI Context

Dev and terminal work only. Strategy, brand, and pilot decisions stay in Claude Code. Use @path references in the AI Composer to pull in specific files before asking questions.

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What Signal Does

Signal is a B2B CGM documentation readiness tracker for DMEPOS suppliers. A supplier exports their order data as a CSV (from Brightree or similar), Signal evaluates each patient against documentation requirements (6-month qualifying visit, PECOS enrollment, SWO, resupply eligibility), and produces a stoplight report so staff can prioritize outreach before claims are submitted.

Signal identifies gaps. It does not contact anyone.

Core value: Shifts supplier staff time from reactive (denial appeals after the fact) to proactive (preventing denial conditions before supplies ship).

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PHI Architecture — Non-Negotiable

• STTIL never stores patient names, SSNs, DOBs, or contact info
• Sole crosswalk key: patient_id (the DME's internal MRN or account number)
• AI/calculation layer sees: patient_id, device_type, shipment_date, quantity, payer — nothing else
• All logs hash patient_id before storing — never raw
• If a proposed change would require storing additional PHI fields, stop and flag it

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Level 1 Stack (Active)

Layer	Tool
Hosting	Hostinger VPS — data never leaves VPS
Language	Python (FastAPI)
Database	PostgreSQL (encrypted at rest, audit logs)
Orchestration	n8n self-hosted (24-hr batch trigger)
Notifications	Self-hosted Mailcow — encrypted email to DME staff only
Frontend	signal-ui/

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Active Files — Start Here

python-backend/core/coverage_calculator.py   # main eligibility logic
python-backend/core/audit_logger.py          # hashed logging
python-backend/config/payer_rules.json       # wear days and payer rules — reference for all calculations
signal-ui/                                   # frontend
research/dmepos-research-v3.md               # full market context + verified stat index (updated May 2026)
research/cgm-market-research-synthesis-v1.md # stat verification summary (May 2026)
docs/hipaa-deployment-analysis-v1.md         # compliance reference
docs/sttil-brand-system-v1.md                # brand (read-only reference)
pitch/                                       # pitch assets and whitepaper

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Market Context — Key Verified Stats (May 2026)

Use these. Do not invent or derive alternatives.

Stat	Source	Use For
30.86% pre-pay error rate	CGS MAC Jurisdiction B Q2 2024	Denial prevention pitch — measures near-submission risk
32.8% error rate / 68.6% from docs	CERT 2019	LinkedIn and public copy — "nearly 1 in 3", "over two-thirds from docs"
67.6% absent documentation	CMS 2024 MLN	Whitepaper / gate framing — post-payment audit
$1.9B DMEPOS improper payments	OIG FY2024	Market context only

Do not use: "94.2%" (derived, not citable), "63% write-off" (modeled, not citable).

Full verified stat table: research/dmepos-research-v3.md Section 14.

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Urgency Anchors (Active)

• Synapse Health mandatory for Medicare CGM: August 1, 2026
• PA exemption cycle (90% affirmation rate): June 1, 2026 first cycle
• 7 new HCPCS codes added to Required PA List: April 13, 2026
• DMEPOS enrollment moratorium in effect: February 27, 2026
• CGM competitive bidding: January 1, 2028

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What Is Tabled — Do Not Build

Item	Why
Dexcom OAuth API	Requires vendor agreement + PHI scope expansion
Prescriber fax automation	Phase 2 — Level 1 manual outreach sufficient
Patient-facing SMS	PHI to third party — needs BAA + consent layer
Consortium / Level 2-3 features	Needs 15+ paying Level 1 suppliers first
Convex	Not needed until real-time sync requirements emerge

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VPS — Common Terax Commands

# Connect
ssh root@72.62.134.75

# Check running Signal services
ssh root@72.62.134.75 "docker ps --format 'table {{.Names}}\t{{.Status}}\t{{.Ports}}'"

# View Signal API logs (live)
ssh root@72.62.134.75 "docker logs signal-api --tail 50 -f"

# Restart Signal API
ssh root@72.62.134.75 "docker compose -f /opt/signal/docker-compose.yml restart signal-api"

# Check Caddy (reverse proxy)
ssh root@72.62.134.75 "docker logs caddy --tail 30"

# Run local tests before deploy
cd python-backend && pytest core/ -v

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Dev Rules

• Work Level 1 scope only
• Reference payer_rules.json for all wear-day calculations — do not hardcode
• Use "resupply" not "refill" (CGM supply allowances are exempt from Medicare refill rules)
• Never suggest adding PHI fields beyond patient_id
• Flag any vendor integration that would require a new BAA
• If asked about Phase 2/3 scope, acknowledge and defer — do not spec or build