From 121b644df49518a7485c378293acee12a5c3b6cb Mon Sep 17 00:00:00 2001
From: Jiang Bohan <bhjiang@outlook.com>
Date: Wed, 11 Feb 2026 17:09:49 +0800
Subject: [PATCH] fix(subagent): inherit parent provider in spawned subagents
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Pass parent's resolvedProvider through the tool chain (tools.ts →
sessions-spawn.ts → hub.createSubagent) so subagents use the same
LLM provider as the parent. Previously subagents fell back to the
hardcoded default provider, causing API key errors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 packages/core/src/agent/tools.ts                | 4 ++++
 packages/core/src/agent/tools/sessions-spawn.ts | 9 +++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/agent/tools.ts b/packages/core/src/agent/tools.ts
index f3908d73..5c203412 100644
--- a/packages/core/src/agent/tools.ts
+++ b/packages/core/src/agent/tools.ts
@@ -26,6 +26,8 @@ export interface CreateToolsOptions {
   isSubagent?: boolean | undefined;
   /** Session ID of the agent (passed to sessions_spawn tool) */
   sessionId?: string | undefined;
+  /** Resolved provider ID of the parent agent (passed to sessions_spawn for subagent inheritance) */
+  provider?: string | undefined;
   /** Callback invoked when exec tool needs approval before running a command */
   onExecApprovalNeeded?: ExecApprovalCallback | undefined;
 }
@@ -131,6 +133,7 @@ export function createAllTools(options: CreateToolsOptions | string): AgentTool<
   const sessionsSpawnTool = createSessionsSpawnTool({
     isSubagent: isSubagent ?? false,
     ...(sessionId !== undefined ? { sessionId } : {}),
+    ...(opts.provider !== undefined ? { provider: opts.provider } : {}),
   });
   tools.push(sessionsSpawnTool as AgentTool<any>);
 
@@ -165,6 +168,7 @@ export function resolveTools(options: ResolveToolsOptions): AgentTool<any>[] {
     profileDir: options.profileDir,
     isSubagent: options.isSubagent,
     sessionId: options.sessionId,
+    provider: options.provider,
     onExecApprovalNeeded: options.onExecApprovalNeeded,
   });
 
diff --git a/packages/core/src/agent/tools/sessions-spawn.ts b/packages/core/src/agent/tools/sessions-spawn.ts
index 35c0017b..7c26de07 100644
--- a/packages/core/src/agent/tools/sessions-spawn.ts
+++ b/packages/core/src/agent/tools/sessions-spawn.ts
@@ -57,6 +57,8 @@ export interface CreateSessionsSpawnToolOptions {
   isSubagent?: boolean;
   /** Session ID of the current (requester) agent */
   sessionId?: string;
+  /** Resolved provider ID of the parent agent (inherited by subagents) */
+  provider?: string;
 }
 
 export function createSessionsSpawnTool(
@@ -67,7 +69,9 @@ export function createSessionsSpawnTool(
     label: "Spawn Subagent",
     description:
       "Spawn a background subagent to handle a specific task. The subagent runs in an isolated session with its own tool set. " +
-      "When it completes, its findings are announced back to you automatically. " +
+      "When it completes, its findings are delivered directly into your context automatically — you do NOT need to poll or check. " +
+      "IMPORTANT: After spawning subagents, continue with any other immediate tasks you have, or simply finish your turn and wait. " +
+      "Do NOT call sessions_list to check on subagents you just spawned — results take time and will arrive on their own. " +
       "Use this for parallelizable work, long-running analysis, or tasks that benefit from isolation.",
     parameters: SessionsSpawnSchema,
     execute: async (_toolCallId, args) => {
@@ -107,6 +111,7 @@ export function createSessionsSpawnTool(
         const childAgent = hub.createSubagent(childSessionId, {
           systemPrompt,
           model,
+          provider: options.provider,
         });
 
         // Register the run for lifecycle tracking.
@@ -127,7 +132,7 @@ export function createSessionsSpawnTool(
           content: [
             {
               type: "text",
-              text: `Subagent spawned successfully.\n\nRun ID: ${runId}\nSession: ${childSessionId}\nTask: ${label || task.slice(0, 80)}\n\nThe subagent is now working in the background. You will receive its findings when it completes.`,
+              text: `Subagent spawned successfully.\n\nRun ID: ${runId}\nSession: ${childSessionId}\nTask: ${label || task.slice(0, 80)}\n\nThe subagent is now working in the background. Its findings will be delivered directly into your context when it completes — do NOT poll or call sessions_list for it. Continue with other tasks or finish your turn.`,
             },
           ],
           details: {