Problem

Pyrite's hooks are per-KB, synchronous, and internal. There's no way for external systems to react to KB events. Use cases that need this:

Slack notification when a QA validation fails

CI trigger when an entry is created or modified

Dashboard update when the knowledge graph changes

"Watch the graph grow" live visualization (extends existing WebSocket #23)

Cross-KB workflows (finding confirmed in KB-A → task created in KB-B)

External agent systems subscribing to KB changes

Solution

Internal Event Bus

Lightweight pub/sub within the Pyrite process:

Events: `entry.created`, `entry.updated`, `entry.deleted`, `qa.validation_failed`, `task.claimed`, `task.completed`, `kb.indexed`, `schema.changed`

Existing hooks migrate to event subscribers (backwards compatible)

WebSocket clients subscribe to event streams (extends #23)

Event payloads include entry ID, KB name, type, actor, timestamp

Webhook Dispatch

External HTTP callbacks:

```yaml

kb.yaml or pyrite.yaml

webhooks: - url: https://hooks.slack.com/... events: [qa.validation_failed] - url: https://ci.example.com/trigger events: [entry.created, entry.updated] filter: kb: project-kb type: backlog_item ```

Async dispatch (don't block the write path)

Retry with exponential backoff

Webhook secret for signature verification

Event Log (optional)

Persist recent events to DB for replay and debugging. Useful for agents that want to "catch up" on what happened while they were offline.

Prerequisites

WebSocket infrastructure (done, #23)

Hook system (done, used by task plugin and QA)

Success Criteria

Internal events fire on all write operations

WebSocket clients can subscribe to filtered event streams

At least one webhook integration working (Slack or generic HTTP)

Existing hooks continue to work unchanged

Event payloads are structured and documented

Launch Context

Not strictly needed for 0.8 alpha, but valuable for the demo site (live graph updates) and corporate adoption (Slack integration). The internal event bus is the foundation — webhooks and external integrations build on top.

Event Bus and Webhook Systembacklog_item