feat(events): Add install-owned event prompts

Add version-controlled event prompt bindings and the first Slack root-message event producer. Route matching events through core dispatch with idempotency and explicit Slack mention suppression.

Also keep the example build test in sync with the dashboard trusted plugin package after rebasing onto main.

Refs GH-435
Co-Authored-By: GPT-5 Codex <codex@openai.com>

Author: dcramer

AGENTS.md

@@ -119,6 +119,7 @@ Co-Authored-By: (agent model name) <email>
 - `specs/context-compaction.md` (reusable Pi history compaction, internal context forks, and visible-thread compaction bounds)
 - `specs/advisor-tool.md` (provider-agnostic advisor tool contract)
 - `specs/scheduler.md` (scheduled Junior task contract)
+- `specs/event-prompts.md` (install-owned event prompt bindings and plugin event definition contract)
 - `specs/trusted-plugin-heartbeat.md` (trusted plugin heartbeat and tool hook contract)
 - `specs/trusted-plugin-dispatch.md` (durable trusted plugin agent dispatch contract)
 - `specs/harness-agent.md` (agent loop and output contract)

packages/junior-plugin-api/src/index.ts

@@ -118,6 +118,43 @@ export interface ToolRegistrationHookContext extends AgentPluginContext {
   userText?: string;
 }
 
+export interface AgentEventEnvelope {
+  actor?: {
+    id?: string;
+    login?: string;
+    type?: string;
+  };
+  event: string;
+  occurredAtMs: number;
+  payload: Record<string, unknown>;
+  scope: Record<string, unknown>;
+  sourceEventId: string;
+  sourceUrl?: string;
+}
+
+export interface AgentEventContextBlockRenderContext {
+  envelope: AgentEventEnvelope;
+}
+
+export interface AgentEventContextBlockDefinition {
+  description: string;
+  render?(ctx: AgentEventContextBlockRenderContext): Promise<string> | string;
+}
+
+export interface AgentEventDeliveryTargetDefinition {
+  description?: string;
+  target: string;
+}
+
+export interface AgentEventDefinition {
+  contextBlocks?: Record<string, AgentEventContextBlockDefinition>;
+  deliveryTargets: AgentEventDeliveryTargetDefinition[];
+  filterKeys?: string[];
+  scopeKeys?: string[];
+}
+
+export interface EventRegistrationHookContext extends AgentPluginContext {}
+
 export interface DispatchOptions {
   credentialSubject?: {
     type: "user";
@@ -214,6 +251,9 @@ export interface AgentPluginHooks {
   tools?(
     ctx: ToolRegistrationHookContext,
   ): Record<string, AgentPluginToolDefinition>;
+  events?(
+    ctx: EventRegistrationHookContext,
+  ): Record<string, AgentEventDefinition>;
   heartbeat?(
     ctx: HeartbeatHookContext,
   ): Promise<HeartbeatResult | void> | HeartbeatResult | void;

packages/junior/src/app.ts

@@ -14,6 +14,7 @@ import {
   setAgentPlugins,
   validateAgentPlugins,
 } from "@/chat/plugins/agent-hooks";
+import { loadEventPromptRegistry } from "@/chat/events/registry";
 import type { PluginConfig } from "@/chat/plugins/types";
 import type {
   AgentPluginRouteMethod,
@@ -237,6 +238,7 @@ export async function createApp(options?: JuniorAppOptions): Promise<Hono> {
       getPluginCatalogSignature();
     }
     agentPluginRoutes = getAgentPluginRoutes();
+    await loadEventPromptRegistry();
   } catch (error) {
     setPluginConfig(previousPluginConfig);
     setAgentPlugins(previousAgentPlugins);