fix(plugin): verify event hook compatibility with v1.4.0

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/hook-message-injector/injector.test.ts

@@ -11,6 +11,7 @@ import {
   generatePartId,
   injectHookMessage,
 } from "./injector"
+import { PART_STORAGE } from "../../shared"
 import { isSqliteBackend, resetSqliteBackendCache } from "../../shared/opencode-storage-detection"
 
 //#region Mocks
@@ -53,6 +54,7 @@ function createMockClient(messages: Array<{
     tools?: Record<string, boolean>
     time?: { created?: number }
   }
+  parts?: Array<{ type?: string }>
 }>): {
   session: {
     messages: (opts: { path: { id: string } }) => Promise<{ data: typeof messages }>
@@ -176,6 +178,24 @@ describe("findNearestMessageWithFieldsFromSDK", () => {
 
     expect(result?.agent).toBe("newest-by-time")
   })
+
+  it("skips compaction marker user messages when resolving nearest message", async () => {
+    const mockClient = createMockClient([
+      {
+        id: "msg_compaction",
+        info: { agent: "atlas", model: { providerID: "openai", modelID: "gpt-5" }, time: { created: 200 } },
+        parts: [{ type: "compaction" }],
+      },
+      {
+        id: "msg_real",
+        info: { agent: "sisyphus", model: { providerID: "anthropic", modelID: "claude-opus-4" }, time: { created: 100 } },
+      },
+    ])
+
+    const result = await findNearestMessageWithFieldsFromSDK(mockClient as any, "ses_123")
+
+    expect(result?.agent).toBe("sisyphus")
+  })
 })
 
 describe("findNearestMessageWithFields JSON backend ordering", () => {
@@ -197,6 +217,34 @@ describe("findNearestMessageWithFields JSON backend ordering", () => {
 
     expect(result?.agent).toBe("newest-by-time")
   })
+
+  it("skips JSON messages whose parts contain a compaction marker", () => {
+    mockIsSqliteBackend.mockReturnValue(false)
+    const messageDir = createMessageDir()
+    const compactionMessageID = "msg_test_injector_compaction_marker"
+    const partDir = join(PART_STORAGE, compactionMessageID)
+    tempDirs.push(partDir)
+
+    writeFileSync(join(messageDir, "msg_0001.json"), JSON.stringify({
+      id: compactionMessageID,
+      agent: "atlas",
+      model: { providerID: "openai", modelID: "gpt-5" },
+      time: { created: 200 },
+    }))
+    mkdirSync(partDir, { recursive: true })
+    writeFileSync(join(partDir, "prt_0001.json"), JSON.stringify({ type: "compaction" }))
+
+    writeFileSync(join(messageDir, "msg_0002.json"), JSON.stringify({
+      id: "msg_0002",
+      agent: "sisyphus",
+      model: { providerID: "anthropic", modelID: "claude-opus-4" },
+      time: { created: 100 },
+    }))
+
+    const result = findNearestMessageWithFields(messageDir)
+
+    expect(result?.agent).toBe("sisyphus")
+  })
 })
 
 describe("findFirstMessageWithAgentFromSDK", () => {
@@ -222,6 +270,17 @@ describe("findFirstMessageWithAgentFromSDK", () => {
     expect(result).toBe("earliest-agent")
   })
 
+  it("skips compaction marker user messages when resolving first agent", async () => {
+    const mockClient = createMockClient([
+      { id: "msg_compaction", info: { agent: "atlas", time: { created: 10 } }, parts: [{ type: "compaction" }] },
+      { id: "msg_real", info: { agent: "sisyphus", time: { created: 20 } } },
+    ])
+
+    const result = await findFirstMessageWithAgentFromSDK(mockClient as any, "ses_123")
+
+    expect(result).toBe("sisyphus")
+  })
+
   it("skips messages without agent field", async () => {
     const mockClient = createMockClient([
       { info: {} },

src/features/hook-message-injector/injector.ts

@@ -7,6 +7,7 @@ import type { MessageMeta, OriginalMessageContext, TextPart, ToolPermission } fr
 import { log } from "../../shared/logger"
 import { isSqliteBackend } from "../../shared/opencode-storage-detection"
 import { createInternalAgentTextPart, normalizeSDKResponse } from "../../shared"
+import { hasCompactionPartInStorage, isCompactionMessage } from "../../shared/compaction-marker"
 
 export interface StoredMessage {
   agent?: string
@@ -32,6 +33,7 @@ interface SDKMessage {
       created?: number
     }
   }
+  parts?: Array<{ type?: string }>
 }
 
 const processPrefix = randomBytes(4).toString("hex")
@@ -39,6 +41,10 @@ let messageCounter = 0
 let partCounter = 0
 
 function convertSDKMessageToStoredMessage(msg: SDKMessage): StoredMessage | null {
+  if (isCompactionMessage(msg)) {
+    return null
+  }
+
   const info = msg.info
   if (!info) return null
 
@@ -164,22 +170,38 @@ export function findNearestMessageWithFields(messageDir: string): StoredMessage
           return {
             fileName,
             msg,
+            hasCompactionMarker: hasCompactionPartInStorage(
+              typeof (msg as { id?: unknown }).id === "string" ? (msg as { id?: string }).id : undefined,
+            ),
             createdAt: typeof msg.time?.created === "number" ? msg.time.created : Number.NEGATIVE_INFINITY,
           }
         } catch {
           return null
         }
       })
-      .filter((entry): entry is { fileName: string; msg: StoredMessage & { time?: { created?: number } }; createdAt: number } => entry !== null)
+      .filter((entry): entry is {
+        fileName: string
+        msg: StoredMessage & { time?: { created?: number } }
+        hasCompactionMarker: boolean
+        createdAt: number
+      } => entry !== null)
       .sort((left, right) => right.createdAt - left.createdAt || right.fileName.localeCompare(left.fileName))
 
     for (const entry of messages) {
+      if (entry.hasCompactionMarker || isCompactionMessage({ agent: entry.msg.agent })) {
+        continue
+      }
+
       if (entry.msg.agent && entry.msg.model?.providerID && entry.msg.model?.modelID) {
         return entry.msg
       }
     }
 
     for (const entry of messages) {
+      if (entry.hasCompactionMarker || isCompactionMessage({ agent: entry.msg.agent })) {
+        continue
+      }
+
       if (entry.msg.agent || (entry.msg.model?.providerID && entry.msg.model?.modelID)) {
         return entry.msg
       }
@@ -216,16 +238,28 @@ export function findFirstMessageWithAgent(messageDir: string): string | null {
           return {
             fileName,
             msg,
+            hasCompactionMarker: hasCompactionPartInStorage(
+              typeof (msg as { id?: unknown }).id === "string" ? (msg as { id?: string }).id : undefined,
+            ),
             createdAt: typeof msg.time?.created === "number" ? msg.time.created : Number.POSITIVE_INFINITY,
           }
         } catch {
           return null
         }
       })
-      .filter((entry): entry is { fileName: string; msg: StoredMessage & { time?: { created?: number } }; createdAt: number } => entry !== null)
+      .filter((entry): entry is {
+        fileName: string
+        msg: StoredMessage & { time?: { created?: number } }
+        hasCompactionMarker: boolean
+        createdAt: number
+      } => entry !== null)
       .sort((left, right) => left.createdAt - right.createdAt || left.fileName.localeCompare(right.fileName))
 
     for (const entry of messages) {
+      if (entry.hasCompactionMarker || isCompactionMessage({ agent: entry.msg.agent })) {
+        continue
+      }
+
       if (entry.msg.agent) {
         return entry.msg.agent
       }