diff --git a/packages/provider-opencode/src/server/adapter.ts b/packages/provider-opencode/src/server/adapter.ts
index 327d4d8cef4f3d7caa50c4b1a2d6ebd3fab3f671..b0b7f0ad29a3b8231e842c58d7a1f5a5366d7ffa 100644
--- a/packages/provider-opencode/src/server/adapter.ts
+++ b/packages/provider-opencode/src/server/adapter.ts
@@ -384,7 +384,6 @@ interface OpenCodeThreadState {
   appThread: OrchestrationV2AppThread | null;
   activeTurn: ActiveOpenCodeTurn | null;
   readonly providerTurns: Map<string, OrchestrationV2ProviderTurn>;
-  readonly messages: Map<string, OrchestrationV2ConversationMessage>;
   readonly runtimeRequests: Map<string, OrchestrationV2RuntimeRequest>;
   readonly messageRoles: Map<string, "user" | "assistant">;
   readonly userMessageIds: Array<string>;
@@ -1257,7 +1256,6 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
               createdAt: startedAt,
               updatedAt: emittedAt,
             };
-            state.messages.set(String(message.id), message);
             yield* emitProviderEvent({
               type: "message.updated",
               driver: OPENCODE_PROVIDER,
@@ -1428,7 +1426,6 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
               appThread: childThread,
               activeTurn: null,
               providerTurns: new Map(),
-              messages: new Map(),
               runtimeRequests: new Map(),
               messageRoles: new Map(),
               userMessageIds: [],
@@ -2336,7 +2333,6 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
             createdAt: turn.startedAt,
             updatedAt: now,
           };
-          state.messages.set(String(messageId), projected);
           yield* emitProviderEvent({
             type: "message.updated",
             driver: OPENCODE_PROVIDER,
@@ -2834,7 +2830,6 @@ export const makeOpenCodeAdapterV2 = Effect.fn("makeOpenCodeAdapterV2")(function
             appThread,
             activeTurn: null,
             providerTurns: new Map(),
-            messages: new Map(),
             runtimeRequests: new Map(),
             messageRoles: new Map(),
             userMessageIds: [],