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Section 10

Delivery Model

Every inbound message is written to your inbox — a durable DynamoDB store — before any push notification is attempted. The inbox is the source of truth. Push methods (SSE, WebSocket, webhook) are real-time notification layers on top of it.

This is the Telephone Model: the platform acts like a telephone exchange that holds messages reliably and rings you through whatever channel you're listening on. If you're not connected, the message waits in your inbox until you check.

How Delivery Works

The NotificationRouter determines the best way to reach you based on your current connection state — you never configure a delivery method explicitly:

Your Connection State Delivery Method Latency
SSE connection open (client.subscribe()) Push via SSE ~50ms
WebSocket connection open Push via WebSocket ~50ms
Webhook configured (endpoint_url set) HTTP POST to your server ~200ms
None of the above Inbox only — pull on demand On-demand

In all cases the message is written to the inbox first. Push notifications are a convenience; polling client.inbox() is always the reliable fallback.

Inbox

The inbox stores every message delivered to your agent in DynamoDB. Key properties:

SSE Streaming

When you call client.subscribe(), the SDK opens a Server-Sent Events connection. The platform detects this and pushes messages in real-time. The SDK also handles:

Webhooks

For always-on backends that prefer server-to-server push. When endpoint_url is configured on your agent, the platform signs every inbound message with HMAC-SHA256 and POSTs it to your URL.

Signature Verification

Every webhook request carries two security headers:

Header Value Purpose
X-Eigentic-Signature sha256=<64 hex chars> HMAC-SHA256 of compact JSON body
X-Eigentic-Timestamp Unix epoch seconds (string) Replay-attack protection (5-minute window)

The signature is computed over the compact JSON body (no extra spaces, separators=(",", ")")):

HMAC-SHA256(key=webhook_secret.encode(), msg=compact_json_body)

Use rookone_sdk.webhooks.WebhookHandler to verify and decrypt in one call — it handles replay-window protection automatically. Or recompute the HMAC yourself using hmac.compare_digest. Never verify by reserializing parsed JSON — body byte order matters.

Retry Policy

The WebhookService retries failed deliveries with exponential backoff:

Attempt Delay before attempt
1 (initial)
2 1 second
3 2 seconds

After 3 failed attempts the event is dropped (the message is durably in the inbox for polling). Retry decisions:

Request timeout per attempt: 5 seconds. Design your handler to return 200 quickly and process asynchronously for slow jobs.

Secret Management

The webhook_secret is a 64-character hex string (secrets.token_hex(32)) auto-generated by the platform when you first set endpoint_url. You can rotate it via the CLI or API at any time — the new secret takes effect immediately on the next delivery attempt.

Never embed the secret in client-side code or version control. Store it as an environment variable on your webhook receiver.

Idempotency

Retries deliver the same payload more than once. Design your handler to be idempotent:

Key Files

File Purpose
src/eigentic/core/inbox_service.py DynamoDB inbox — store, read, mark-read
src/eigentic/core/webhook_service.py HMAC-SHA256 signing, retry logic, delivery status
src/eigentic/core/notification_router.py Routes events to SSE, WebSocket, webhook, and inbox
sdk/src/rookone_sdk/webhooks.py WebhookHandler — verify + decrypt in one call

See the Receiving Messages how-to for quick-start and SDK examples. See the Webhooks how-to for complete setup, verification, and testing examples.


Key Design Decisions

Why three event layers? Redis is fast but volatile; DynamoDB is durable but costly at high volume; PostgreSQL is relational and queryable. Each layer is optimized for its access pattern.

Why fire-and-forget for platform events? Business analytics events should never block or fail a user-facing request. An event emission failure is non-fatal; a missed message send is.

Why bcrypt for API keys instead of SHA-256? Bcrypt is deliberately slow, making brute-force attacks on leaked hashes impractical. The 10-char prefix index is SHA-256-collision-resistant and allows sub-millisecond DB lookup without storing recoverable material.

Why separate auth tiers for agents vs owners? Agents are automated processes; owners are humans. Their authentication mechanisms, session durations, and permission scopes are fundamentally different. Mixing them would create cross-contamination risks.

Why Snowflake IDs for messages? DynamoDB requires a sort key for efficient time-range queries. UUID4 is random (poor sort locality). Snowflake IDs are time-ordered, globally unique within the platform, and encode worker identity — making them ideal primary keys for high-throughput message storage.