From 093fa92e7f4f902e17800741c26adcc8a3826c6c Mon Sep 17 00:00:00 2001
From: Daniel Smolsky <dannysmo@gmail.com>
Date: Tue, 6 Jan 2026 13:48:25 -0500
Subject: [PATCH] fix: remove isInternalAgent flag due to hook ordering race
 condition

The isInternalAgent flag was causing a race condition where concurrent
internal agents (title/summary generators) would set the flag to true,
and normal session message transforms would see the stale value and skip
injecting the prunable-tools list.

This happened because messages.transform runs before system.transform,
so the flag set by system.transform was always stale by the time
messages.transform checked it.

Fix: Remove the flag entirely and only skip system prompt injection for
internal agents (detected in system.transform where it works reliably).
---
 index.ts           | 6 +-----
 lib/hooks.ts       | 2 +-
 lib/state/state.ts | 2 --
 lib/state/types.ts | 1 -
 4 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/index.ts b/index.ts
index 28b4a6c..2372d2c 100644
--- a/index.ts
+++ b/index.ts
@@ -37,14 +37,10 @@ const plugin: Plugin = (async (ctx) => {
                 "Summarize what was done in this conversation",
             ]
             if (internalAgentSignatures.some((sig) => systemText.includes(sig))) {
-                logger.info("Skipping DCP injection for internal agent")
-                state.isInternalAgent = true
+                logger.info("Skipping DCP system prompt injection for internal agent")
                 return
             }
 
-            // Reset flag for normal sessions
-            state.isInternalAgent = false
-
             const discardEnabled = config.tools.discard.enabled
             const extractEnabled = config.tools.extract.enabled
 
diff --git a/lib/hooks.ts b/lib/hooks.ts
index 231357d..e70c892 100644
--- a/lib/hooks.ts
+++ b/lib/hooks.ts
@@ -15,7 +15,7 @@ export function createChatMessageTransformHandler(
     return async (input: {}, output: { messages: WithParts[] }) => {
         await checkSession(client, state, logger, output.messages)
 
-        if (state.isSubAgent || state.isInternalAgent) {
+        if (state.isSubAgent) {
             return
         }
 
diff --git a/lib/state/state.ts b/lib/state/state.ts
index a85d61e..e68ecf8 100644
--- a/lib/state/state.ts
+++ b/lib/state/state.ts
@@ -43,7 +43,6 @@ export function createSessionState(): SessionState {
     return {
         sessionId: null,
         isSubAgent: false,
-        isInternalAgent: false,
         prune: {
             toolIds: [],
         },
@@ -63,7 +62,6 @@ export function createSessionState(): SessionState {
 export function resetSessionState(state: SessionState): void {
     state.sessionId = null
     state.isSubAgent = false
-    state.isInternalAgent = false
     state.prune = {
         toolIds: [],
     }
diff --git a/lib/state/types.ts b/lib/state/types.ts
index 9d72e19..1e41170 100644
--- a/lib/state/types.ts
+++ b/lib/state/types.ts
@@ -27,7 +27,6 @@ export interface Prune {
 export interface SessionState {
     sessionId: string | null
     isSubAgent: boolean
-    isInternalAgent: boolean
     prune: Prune
     stats: SessionStats
     toolParameters: Map<string, ToolParameterEntry>