From d481c596bde619b031cb196e795dd19938a1fd71 Mon Sep 17 00:00:00 2001
From: justsisyphus <justsisyphus@users.noreply.github.com>
Date: Tue, 27 Jan 2026 15:17:27 +0900
Subject: [PATCH] fix(plan-agent): only inherit model from prometheus as
 fallback

Plan agent was incorrectly inheriting prometheus's entire config (prompt,
permission, etc.) causing it to behave as primary instead of subagent.

Now plan agent:
1. Uses plan config model if explicitly set
2. Falls back to prometheus model only if plan config has no model
3. Keeps original OpenCode plan config intact
---
 src/plugin-handlers/config-handler.ts | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/plugin-handlers/config-handler.ts b/src/plugin-handlers/config-handler.ts
index 123f806d5..7770b848b 100644
--- a/src/plugin-handlers/config-handler.ts
+++ b/src/plugin-handlers/config-handler.ts
@@ -306,8 +306,15 @@ export function createConfigHandler(deps: ConfigHandlerDeps) {
         ? migrateAgentConfig(configAgent.build as Record<string, unknown>)
         : {};
 
-      const planDemoteConfig = replacePlan && agentConfig["prometheus"]
-        ? { ...agentConfig["prometheus"], name: "plan", mode: "subagent" as const }
+      const prometheusModel = (agentConfig["prometheus"] as { model?: string })?.model;
+      const planConfigModel = (configAgent?.plan as { model?: string })?.model;
+      const planDemoteConfig = replacePlan && (planConfigModel || prometheusModel)
+        ? { 
+            ...configAgent?.plan,
+            model: planConfigModel || prometheusModel,
+            name: "plan", 
+            mode: "subagent" as const 
+          }
         : undefined;
 
       config.agent = {