diff --git a/src/mnemosyne/gateway.py b/src/mnemosyne/gateway.py
index 0428e08..070763c 100644
--- a/src/mnemosyne/gateway.py
+++ b/src/mnemosyne/gateway.py
@@ -1610,21 +1610,25 @@ def create_app(
         # 4. Build ephemeral outbound view — never mutate the physical store
         payload["messages"] = copy.deepcopy(ms.messages)
 
-        # 4a. Inject phantom tool definitions and resolve pending calls
-        from mnemosyne.phantom import inject_tools, inject_phantom_results, extract_phantom_calls
-
-        observe_only = inject_tools(payload)
-        # Check for pending phantom calls from the previous assistant turn
-        pending_calls = extract_phantom_calls(payload.get("messages", []))
-        if pending_calls:
-            inject_phantom_results(
-                payload["messages"],
-                pending_calls,
-                ps,
-                observe_only,
-                context_assembler=session.context_assembler,
-                session_id=session.id,
-            )
+        # 4a. Phantom tool injection — DISABLED when proxying for opencode.
+        # opencode validates tool calls against its own registry and rejects
+        # unknown tools like memory_query.  Phantom tools require SSE stream
+        # interception + auto-continue which the gateway doesn't implement
+        # for the pass-through streaming path.  The opencode plugin provides
+        # mnemosyne_query/mnemosyne_status as registered MCP tools instead.
+        #
+        # from mnemosyne.phantom import inject_tools, inject_phantom_results, extract_phantom_calls
+        # observe_only = inject_tools(payload)
+        # pending_calls = extract_phantom_calls(payload.get("messages", []))
+        # if pending_calls:
+        #     inject_phantom_results(
+        #         payload["messages"],
+        #         pending_calls,
+        #         ps,
+        #         observe_only,
+        #         context_assembler=session.context_assembler,
+        #         session_id=session.id,
+        #     )
 
         # 4b. Apply fidelity-based content replacement
         _apply_fidelity(payload, session)