diff --git a/package.json b/package.json
index dc1d45a..ca074db 100644
--- a/package.json
+++ b/package.json
@@ -46,15 +46,18 @@
   },
   "dependencies": {
     "@langfuse/otel": "^5.10.1",
-    "@opencode-ai/plugin": "^1.18.19",
     "@opentelemetry/api": "^1.9.1",
     "@opentelemetry/resources": "^2.10.0",
     "@opentelemetry/sdk-trace-base": "^2.10.0",
     "@opentelemetry/sdk-trace-node": "^2.10.0",
     "effect": "^3.22.1"
   },
+  "peerDependencies": {
+    "@opencode-ai/plugin": "^1.18.19"
+  },
   "devDependencies": {
     "@eslint/js": "^10.0.1",
+    "@opencode-ai/plugin": "^1.18.19",
     "@types/node": "^26.1.2",
     "eslint": "^10.8.1",
     "knip": "^6.32.2",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 722d41e..8abbc89 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -11,9 +11,6 @@ importers:
       '@langfuse/otel':
         specifier: ^5.10.1
         version: 5.10.1(@opentelemetry/api@1.9.1)(@opentelemetry/core@2.10.0(@opentelemetry/api@1.9.1))(@opentelemetry/exporter-trace-otlp-http@0.221.0(@opentelemetry/api@1.9.1))(@opentelemetry/sdk-trace-base@2.10.0(@opentelemetry/api@1.9.1))
-      '@opencode-ai/plugin':
-        specifier: ^1.18.19
-        version: 1.18.19
       '@opentelemetry/api':
         specifier: ^1.9.1
         version: 1.9.1
@@ -33,6 +30,9 @@ importers:
       '@eslint/js':
         specifier: ^10.0.1
         version: 10.0.1(eslint@10.8.1(jiti@2.7.0))
+      '@opencode-ai/plugin':
+        specifier: ^1.18.19
+        version: 1.18.19
       '@types/node':
         specifier: ^26.1.2
         version: 26.1.2
diff --git a/src/schema.ts b/src/schema.ts
index 1ac7a27..def6788 100644
--- a/src/schema.ts
+++ b/src/schema.ts
@@ -249,7 +249,7 @@ type CurrentSessionNextEvent =
   | SessionNextCompactionEndedEvent;
 
 // https://github.com/anomalyco/opencode/blob/v1.18.19/packages/schema/src/session-event.ts#L479-L517
-export type SessionNextEvent = LegacySessionNextEvent | CurrentSessionNextEvent;
+type SessionNextEvent = LegacySessionNextEvent | CurrentSessionNextEvent;
 
 // https://github.com/anomalyco/opencode/blob/v1.18.19/packages/plugin/src/index.ts#L222-L224
 export type OpencodeEvent =
@@ -277,7 +277,7 @@ export const McpToolResultSchema = Schema.Struct({
 });
 
 // https://github.com/anomalyco/opencode/blob/v1.18.19/packages/opencode/src/session/tools.ts#L436-L461
-export const McpResourceContentsSchema = Schema.Union(
+const McpResourceContentsSchema = Schema.Union(
   Schema.Struct({
     uri: Schema.String,
     mimeType: Schema.optional(Schema.String),
diff --git a/test/integration/plugin.test.ts b/test/integration/plugin.test.ts
index c8eccb9..7d2693a 100644
--- a/test/integration/plugin.test.ts
+++ b/test/integration/plugin.test.ts
@@ -14,7 +14,12 @@ import {
   test,
 } from "vitest";
 
-import type { SessionNextEvent } from "../../src/schema.js";
+import type { OpencodeEvent } from "../../src/schema.js";
+
+type SessionNextEvent = Extract<
+  OpencodeEvent,
+  { type: `session.next.${string}` }
+>;
 
 const OtlpValueSchema = Schema.Struct({
   stringValue: Schema.optional(Schema.String),
@@ -276,7 +281,8 @@ const startGeneration = async (input: {
     properties: {
       sessionID: input.sessionID,
       timestamp: input.started,
-      ...(input.assistantMessageID
+      ...(input.assistantMessageID !== undefined &&
+      input.assistantMessageID !== ""
         ? { assistantMessageID: input.assistantMessageID }
         : {}),
       agent: "build",