feat(server): support reading subagent transcripts

Add fallback in readSessionMessages() to locate subagent transcript files under <project>/<session>/subagents/agent-<id>.jsonl when the sessionId is actually an agentId. Extract entryToSessionMessage and readMessagesFromLines helpers for reuse between main and subagent transcripts.

Also route 'system' messages through the 'message' event in sessionMessageRouter so subscribers can observe them.

Signed-off-by: 林凯90331 <90331@sangfor.com>
Co-authored-by: CoStrict <zgsm@sangfor.com.cn>

src/server/sessionMessageRouter.ts

@@ -88,6 +88,10 @@ export function routeMessage(msg: StdoutMessage, ctx: MessageRouterCtx): void {
       ctx.emitEvent('stream_event', msg)
       break
     }
+    case 'system': {
+      ctx.emitEvent('message', msg)
+      break
+    }
     default: {
       break
     }

src/server/transcriptReader.ts

@@ -112,6 +112,142 @@ function parseEntry(line: string): TranscriptEntry | null {
   return parsed as TranscriptEntry
 }
 
+function entryToSessionMessage(
+  entry: TranscriptEntry,
+  includeSystem: boolean,
+): SessionMessage | null {
+  if (!entry.type || !entry.uuid) return null
+  if (SKIP_TYPES.has(entry.type)) return null
+  if (entry.type === 'attribution-snapshot') return null
+
+  const includeThis =
+    MESSAGE_TYPES.has(entry.type) ||
+    (includeSystem && entry.type === 'system')
+
+  if (!includeThis) return null
+
+  const role = entry.role ?? entry.message?.role ?? entry.type
+  const content = entry.message?.content ?? entry.content ?? ''
+  const timestamp = entry.timestamp
+    ? new Date(entry.timestamp).getTime()
+    : 0
+
+  return {
+    uuid: entry.uuid,
+    type: entry.type,
+    role: role ?? entry.type,
+    content,
+    timestamp,
+    parent_uuid: entry.parentUuid ?? null,
+    usage: entry.usage as
+      | { input_tokens: number; output_tokens: number }
+      | undefined,
+  }
+}
+
+function readMessagesFromLines(
+  lines: string[],
+  includeSystem: boolean,
+): SessionMessage[] {
+  const messages: SessionMessage[] = []
+  for (const line of lines) {
+    if (!line) continue
+    const entry = parseEntry(line)
+    if (!entry) continue
+    const msg = entryToSessionMessage(entry, includeSystem)
+    if (msg) messages.push(msg)
+  }
+  return messages
+}
+
+/**
+ * Locate the subagent transcript file for a given agentId by scanning
+ * `<projectsDir>/<project>/<parentSessionId>/subagents/agent-<agentId>.jsonl`.
+ *
+ * `cwd` is used to narrow the search to a specific project dir; if omitted or
+ * not matched, we fall back to scanning every project directory.
+ */
+async function findSubagentTranscriptPath(
+  agentId: string,
+  cwd?: string,
+): Promise<string | null> {
+  const fileName = `agent-${agentId}.jsonl`
+
+  const searchProject = async (projectDir: string): Promise<string | null> => {
+    let sessionDirs: string[]
+    try {
+      sessionDirs = await readdir(projectDir)
+    } catch {
+      return null
+    }
+    for (const sessionDir of sessionDirs) {
+      const direct = join(projectDir, sessionDir, 'subagents', fileName)
+      try {
+        const s = await stat(direct)
+        if (s.isFile() && s.size > 0) return direct
+      } catch {
+      }
+      const nestedSubagentsDir = join(projectDir, sessionDir, 'subagents')
+      let subdirs: string[]
+      try {
+        subdirs = await readdir(nestedSubagentsDir)
+      } catch {
+        continue
+      }
+      for (const sub of subdirs) {
+        const candidate = join(nestedSubagentsDir, sub, fileName)
+        try {
+          const s = await stat(candidate)
+          if (s.isFile() && s.size > 0) return candidate
+        } catch {
+        }
+      }
+    }
+    return null
+  }
+
+  if (cwd) {
+    const projectDir = getProjectDir(cwd)
+    const hit = await searchProject(projectDir)
+    if (hit) return hit
+
+    const found = await findProjectDir(cwd)
+    if (found && found !== projectDir) {
+      const hit2 = await searchProject(found)
+      if (hit2) return hit2
+    }
+  }
+
+  const projectsDir = getProjectsDir()
+  let dirs: string[]
+  try {
+    dirs = await readdir(projectsDir)
+  } catch {
+    return null
+  }
+  for (const dir of dirs) {
+    const hit = await searchProject(join(projectsDir, dir))
+    if (hit) return hit
+  }
+  return null
+}
+
+async function readSubagentMessages(
+  agentId: string,
+  cwd: string | undefined,
+  includeSystem: boolean,
+): Promise<SessionMessage[]> {
+  const path = await findSubagentTranscriptPath(agentId, cwd)
+  if (!path) return []
+  try {
+    const raw = await readFile(path, 'utf-8')
+    const lines = raw.split('\n')
+    return readMessagesFromLines(lines, includeSystem)
+  } catch {
+    return []
+  }
+}
+
 export async function readSessionMessages(opts: {
   sessionId: string
   cwd?: string
@@ -122,66 +258,43 @@ export async function readSessionMessages(opts: {
   messages: SessionMessage[]
   nextCursor?: string
 }> {
+  const includeSystem = opts.includeSystem ?? false
   const path = await resolveTranscriptPath(opts.sessionId, opts.cwd)
-  if (!path || !existsSync(path)) {
-    return { messages: [] }
-  }
 
-  const raw = await readFile(path, 'utf-8')
-  const lines = raw.split('\n').filter(Boolean)
+  let mainMessages: SessionMessage[] = []
+  if (path && existsSync(path)) {
+    const raw = await readFile(path, 'utf-8')
+    const lines = raw.split('\n').filter(Boolean)
 
-  let lastCompactBoundaryIndex = -1
-  for (let i = lines.length - 1; i >= 0; i--) {
-    const entry = parseEntry(lines[i])
-    if (
-      entry?.type === 'system' &&
-      entry?.subtype === 'compact_boundary' &&
-      !entry?.compactMetadata?.preservedSegment
-    ) {
-      lastCompactBoundaryIndex = i
-      break
+    let lastCompactBoundaryIndex = -1
+    for (let i = lines.length - 1; i >= 0; i--) {
+      const entry = parseEntry(lines[i])
+      if (
+        entry?.type === 'system' &&
+        entry?.subtype === 'compact_boundary' &&
+        !entry?.compactMetadata?.preservedSegment
+      ) {
+        lastCompactBoundaryIndex = i
+        break
+      }
+    }
+
+    const startLine = lastCompactBoundaryIndex >= 0 ? lastCompactBoundaryIndex + 1 : 0
+    mainMessages = readMessagesFromLines(lines.slice(startLine), includeSystem)
+  } else {
+    // Fallback: 视 sessionId 为 agentId，读取 subagent transcript。
+    mainMessages = await readSubagentMessages(opts.sessionId, opts.cwd, includeSystem)
+    if (mainMessages.length === 0) {
+      return { messages: [] }
     }
   }
 
-  const startLine = lastCompactBoundaryIndex >= 0 ? lastCompactBoundaryIndex + 1 : 0
+  const allMessages = mainMessages
+  allMessages.sort((a, b) => a.timestamp - b.timestamp)
 
-  const allMessages: SessionMessage[] = []
   let cursorIndex = -1
-
-  for (let i = startLine; i < lines.length; i++) {
-    const entry = parseEntry(lines[i])
-    if (!entry) continue
-    if (!entry.type || !entry.uuid) continue
-    if (SKIP_TYPES.has(entry.type)) continue
-    if (entry.type === 'attribution-snapshot') continue
-
-    const includeThis =
-      MESSAGE_TYPES.has(entry.type) ||
-      (opts.includeSystem && entry.type === 'system')
-
-    if (!includeThis) continue
-
-    if (entry.uuid === opts.before) {
-      cursorIndex = allMessages.length
-    }
-
-    const role = entry.role ?? entry.message?.role ?? entry.type
-    const content = entry.message?.content ?? entry.content ?? ''
-    const timestamp = entry.timestamp
-      ? new Date(entry.timestamp).getTime()
-      : 0
-
-    allMessages.push({
-      uuid: entry.uuid,
-      type: entry.type,
-      role: role ?? entry.type,
-      content,
-      timestamp,
-      parent_uuid: entry.parentUuid ?? null,
-      usage: entry.usage as
-        | { input_tokens: number; output_tokens: number }
-        | undefined,
-    })
+  if (opts.before) {
+    cursorIndex = allMessages.findIndex(m => m.uuid === opts.before)
   }
 
   const startIndex = cursorIndex >= 0 ? cursorIndex + 1 : 0