diff --git a/paperforge/config.py b/paperforge/config.py
index 403c34b8..8f634566 100644
--- a/paperforge/config.py
+++ b/paperforge/config.py
@@ -55,7 +55,6 @@ DEFAULT_CONFIG: dict[str, str] = {
     "base_dir": "Bases",
     "skill_dir": ".opencode/skills",
     "command_dir": ".opencode/command",
-    "agent_platform": "opencode",
 }
 
 # Environment variable name map — maps config key to PAPERFORGE_* env var
diff --git a/paperforge/worker/update.py b/paperforge/worker/update.py
index edd95970..0f4bcfe9 100644
--- a/paperforge/worker/update.py
+++ b/paperforge/worker/update.py
@@ -269,9 +269,12 @@ def _deploy_all_skills(vault: Path) -> None:
         from paperforge.config import load_vault_config
 
         config = load_vault_config(vault)
+        # Agent platform is a user preference, not a system default.
+        # Fall back to opencode if not configured.
+        agent_key = config.get("agent_platform") or "opencode"
         result = deploy_skills(
             vault=vault,
-            agent_key=config.get("agent_platform", "opencode"),
+            agent_key=agent_key,
             system_dir=config.get("system_dir", "System"),
             resources_dir=config.get("resources_dir", "Resources"),
             literature_dir=config.get("literature_dir", "Literature"),