perf: avoid redundant isSubagentSession API calls

Author: Tarquinen

lib/hooks.ts

@@ -75,14 +75,12 @@ export function createChatParamsHandler(
         // Track the last seen session ID for fetch wrapper correlation
         state.lastSeenSessionId = sessionId
 
-        // Check if this is a subagent session and track it to skip fetch wrapper processing
-        if (!state.subagentSessions.has(sessionId)) {
+        // Check if this is a subagent session
+        if (!state.checkedSessions.has(sessionId)) {
+            state.checkedSessions.add(sessionId)
             const isSubagent = await isSubagentSession(client, sessionId)
             if (isSubagent) {
                 state.subagentSessions.add(sessionId)
-                logger.info("chat.params", "Detected subagent session, will skip DCP processing", {
-                    sessionId: sessionId.substring(0, 8)
-                })
             }
         }
 

lib/state.ts

@@ -22,6 +22,8 @@ export interface PluginState {
     googleToolCallMapping: Map<string, Map<string, string>>
     /** Set of session IDs that have been restored from disk */
     restoredSessions: Set<string>
+    /** Set of session IDs we've already checked for subagent status (to avoid redundant API calls) */
+    checkedSessions: Set<string>
     /** Set of session IDs that are subagents (have a parentID) - used to skip fetch wrapper processing */
     subagentSessions: Set<string>
     /** The most recent session ID seen in chat.params - used to correlate fetch requests */
@@ -49,6 +51,7 @@ export function createPluginState(): PluginState {
         model: new Map(),
         googleToolCallMapping: new Map(),
         restoredSessions: new Set(),
+        checkedSessions: new Set(),
         subagentSessions: new Set(),
         lastSeenSessionId: null,
     }