Snowflake decision publication service¶


ID	`MOD-079`
System	SD07
Repo	`bank-platform`
Build status	Deployed
Deployed	Yes
Last commit	`39bbf8c1b8255fa6429add330de438d2899dc558`

The Snowflake decision publication service is the operational apply service defined in ADR-036. It is the only governed path by which Snowflake-generated decisions cross the Snowflake → Neon boundary and take operational effect.

Purpose¶

Snowflake produces decisions — onboarding outcomes, CDD tier assignments, fraud actions, credit pre-approvals, AML case escalations. These decisions must be applied to Neon's operational tables to change how the bank treats a customer. Without a governed publication path, decisions either do not take effect or require ad-hoc database writes that undermine auditability.

This module receives published decision payloads on the decision_inbox.decision_result_inbox table in Neon, validates the contract version and schema, deduplicates on the idempotency_key, and applies the decision to the correct operational table. Every applied decision is recorded in decision_delivery_log with its source computation, contract version, policy references, and effective timestamp.

What it does¶

Receives versioned decision payloads from Snowflake's decision_curated.decision_result view via the ADR-036 publication contract
Validates schema version, entity type, and mandatory fields before applying anything
Deduplicates on decision_id + idempotency_key — safe to replay without double-applying
Routes each decision type to its target operational table: onboarding → customers.onboarding_status; CDD tier → customers.cdd_tier; fraud action → accounts.status; credit pre-approval → credit_decisions; AML escalation → aml_cases.status
Logs every outcome — applied, duplicate, rejected — to decision_delivery_log

What it does not do¶

This module does not write Tier 3 reporting data. It does not receive raw Snowflake features or intermediate model scores. It does not accept direct database writes from Snowflake — all traffic arrives via the ADR-036 decision inbox contract. For the data tier classification see ADR-038.

Failure handling¶

If the apply step fails after successful inbox receipt, the record remains in the inbox with a failed status and is retried. Dead-letter records older than 24 hours are escalated via the operations work queue (MOD-064). Snowflake does not retry — the inbox record is the durable state.

Module dependencies¶

Depends on¶

Module	Title	Required?	Contract	Reason
MOD-042	CDC pipeline — Neon logical replication to S3 Iceberg	Required	—	Decision publication writes back to operational Neon databases — requires the CDC pipeline infrastructure to be established for the reverse flow.
MOD-104	AWS shared infrastructure bootstrap	Required	—	AWS shared infrastructure provisioned by MOD-104 (EventBridge buses, S3, KMS, Kinesis, Cognito) is required before this module can be deployed.

Required by¶

Module	Title	As	Contract
MOD-048	System decision log	Hard dependency	—
MOD-105	Product eligibility engine	Hard dependency	—
MOD-147	Related party exposure monitor	Hard dependency	—

Policies satisfied¶

Policy	Title	Mode	How
GOV-006	Internal Audit Policy	`LOG`	Every applied decision is recorded with its source Snowflake computation, contract version, policy reference, and operator identity — immutable audit trail.
DT-001	Information Security Policy	`GATE`	Only schema-version-validated, policy-sanctioned outcomes cross the Snowflake → Neon boundary — raw features and intermediate scores never leave Snowflake.

Capabilities satisfied¶

Capability	Title	Mode	How
CAP-125	Snowflake write-back API (internal)	`AUTO`	Receives versioned decision payloads from Snowflake, deduplicates on idempotency key, validates contract version, and applies the decision to the appropriate Neon operational table via the decision inbox.

Part of SD07 — Data Platform & Governance Infrastructure Compiled 2026-05-22 from source/entities/modules/MOD-079.yaml