feat(hook): session.before.idle

packages/opencode/src/session/prompt.ts

@@ -622,6 +622,25 @@ export namespace SessionPrompt {
       continue
     }
     SessionCompaction.prune({ sessionID })
+
+    // Allow plugins to optionally resume this session before it completes
+    const sessionInfo = await Session.get(sessionID)
+    const beforeIdleOutput = { resumePrompt: undefined as string | undefined }
+    await Plugin.trigger("session.before.idle", { sessionID, parentSessionID: sessionInfo?.parentID }, beforeIdleOutput)
+
+    if (beforeIdleOutput.resumePrompt) {
+      log.info("resuming session", { sessionID })
+      delete state()[sessionID]
+      const resumeAgent = await lastAgent(sessionID)
+      const resumeModel = await lastModel(sessionID)
+      await prompt({
+        sessionID,
+        agent: resumeAgent,
+        model: resumeModel,
+        parts: [{ type: "text", text: beforeIdleOutput.resumePrompt }],
+      })
+    }
+
     for await (const item of MessageV2.stream(sessionID)) {
       if (item.info.role === "user") continue
       const queued = state()[sessionID]?.callbacks ?? []
@@ -640,6 +659,13 @@ export namespace SessionPrompt {
     return Provider.defaultModel()
   }
 
+  async function lastAgent(sessionID: string) {
+    for await (const item of MessageV2.stream(sessionID)) {
+      if (item.info.role === "user" && item.info.agent) return item.info.agent
+    }
+    return Agent.defaultAgent()
+  }
+
   async function resolveTools(input: {
     agent: Agent.Info
     model: Provider.Model

packages/plugin/src/index.ts

@@ -215,4 +215,9 @@ export interface Hooks {
     input: { sessionID: string; messageID: string; partID: string },
     output: { text: string },
   ) => Promise<void>
+
+  "session.before.idle"?: (
+    input: { sessionID: string; parentSessionID?: string },
+    output: { resumePrompt?: string },
+  ) => Promise<void>
 }