diff --git a/packages/provider-opencode/src/server/adapter.test.ts b/packages/provider-opencode/src/server/adapter.test.ts
index 2ef7f2c5bbd02..5313eb72a9d8f 100644
--- a/packages/provider-opencode/src/server/adapter.test.ts
+++ b/packages/provider-opencode/src/server/adapter.test.ts
@@ -2507,7 +2507,14 @@ describe("OpenCodeAdapterV2", () => {
         method: "session.prompt",
         payload: { prompt: secret, nested: { token: secret } },
       });
+      yield* logProtocolEvent({
+        direction: "incoming",
+        messageKind: "notification",
+        method: "message.part.delta",
+        payload: { type: "message.part.delta", properties: { delta: secret } },
+      });
 
+      assert.lengthOf(records, 1);
       const serialized = encodeUnknownJson(records);
       assert.notInclude(serialized, secret);
       assert.include(serialized, '"protocol":"opencode-sdk.sse"');
diff --git a/packages/provider-opencode/src/server/adapter.ts b/packages/provider-opencode/src/server/adapter.ts
index 271259631ea4c..b32528257944f 100644
--- a/packages/provider-opencode/src/server/adapter.ts
+++ b/packages/provider-opencode/src/server/adapter.ts
@@ -446,7 +446,8 @@ export function makeOpenCodeProtocolLogger(input: {
 }): (event: OpenCodeProtocolLogEvent) => Effect.Effect<void, never> {
   return (event) =>
     Effect.gen(function* () {
-      if (!input.nativeEventLogger) return;
+      // Per-token deltas; the part's final message.part.updated is still logged.
+      if (!input.nativeEventLogger || event.method === "message.part.delta") return;
       const observedAt = DateTime.formatIso(yield* DateTime.now);
       const method = structuralProtocolMethod(event.method);
       yield* input.nativeEventLogger.write(