diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 3f433e0eb3..e49aaf875b 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -17,7 +17,31 @@ function mimeToModality(mime: string): Modality | undefined {
 }
 
 export namespace ProviderTransform {
-  function normalizeMessages(msgs: ModelMessage[], model: Provider.Model): ModelMessage[] {
+  function normalizeMessages(
+    msgs: ModelMessage[],
+    model: Provider.Model,
+    options: Record<string, unknown>,
+  ): ModelMessage[] {
+    // Strip openai itemId metadata when store=false to avoid sending stale IDs
+    if (model.api.npm === "@ai-sdk/openai" && options.store === false) {
+      msgs = msgs.map((msg) => {
+        if (!Array.isArray(msg.content)) return msg
+        const content = msg.content.map((part) => {
+          if (!part.providerOptions?.openai) return part
+          const { itemId, reasoningEncryptedContent, ...rest } = part.providerOptions.openai as Record<string, unknown>
+          const openai = Object.keys(rest).length > 0 ? rest : undefined
+          return {
+            ...part,
+            providerOptions: {
+              ...part.providerOptions,
+              openai,
+            },
+          }
+        })
+        return { ...msg, content } as typeof msg
+      })
+    }
+
     // Anthropic rejects messages with empty content - filter out empty string messages
     // and remove empty text/reasoning parts from array content
     if (model.api.npm === "@ai-sdk/anthropic") {
@@ -219,9 +243,9 @@ export namespace ProviderTransform {
     })
   }
 
-  export function message(msgs: ModelMessage[], model: Provider.Model) {
+  export function message(msgs: ModelMessage[], model: Provider.Model, options: Record<string, unknown>) {
     msgs = unsupportedParts(msgs, model)
-    msgs = normalizeMessages(msgs, model)
+    msgs = normalizeMessages(msgs, model, options)
     if (
       model.providerID === "anthropic" ||
       model.api.id.includes("anthropic") ||
diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index c8852edad0..7ad856bf0d 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -218,7 +218,7 @@ export namespace LLM {
             async transformParams(args) {
               if (args.type === "stream") {
                 // @ts-expect-error
-                args.params.prompt = ProviderTransform.message(args.params.prompt, input.model)
+                args.params.prompt = ProviderTransform.message(args.params.prompt, input.model, options)
               }
               return args.params
             },
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 61da69332e..6a28d77c93 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -261,40 +261,44 @@ describe("ProviderTransform.message - DeepSeek reasoning content", () => {
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, {
-      id: "deepseek/deepseek-chat",
-      providerID: "deepseek",
-      api: {
-        id: "deepseek-chat",
-        url: "https://api.deepseek.com",
-        npm: "@ai-sdk/openai-compatible",
-      },
-      name: "DeepSeek Chat",
-      capabilities: {
-        temperature: true,
-        reasoning: true,
-        attachment: false,
-        toolcall: true,
-        input: { text: true, audio: false, image: false, video: false, pdf: false },
-        output: { text: true, audio: false, image: false, video: false, pdf: false },
-        interleaved: {
-          field: "reasoning_content",
+    const result = ProviderTransform.message(
+      msgs,
+      {
+        id: "deepseek/deepseek-chat",
+        providerID: "deepseek",
+        api: {
+          id: "deepseek-chat",
+          url: "https://api.deepseek.com",
+          npm: "@ai-sdk/openai-compatible",
         },
+        name: "DeepSeek Chat",
+        capabilities: {
+          temperature: true,
+          reasoning: true,
+          attachment: false,
+          toolcall: true,
+          input: { text: true, audio: false, image: false, video: false, pdf: false },
+          output: { text: true, audio: false, image: false, video: false, pdf: false },
+          interleaved: {
+            field: "reasoning_content",
+          },
+        },
+        cost: {
+          input: 0.001,
+          output: 0.002,
+          cache: { read: 0.0001, write: 0.0002 },
+        },
+        limit: {
+          context: 128000,
+          output: 8192,
+        },
+        status: "active",
+        options: {},
+        headers: {},
+        release_date: "2023-04-01",
       },
-      cost: {
-        input: 0.001,
-        output: 0.002,
-        cache: { read: 0.0001, write: 0.0002 },
-      },
-      limit: {
-        context: 128000,
-        output: 8192,
-      },
-      status: "active",
-      options: {},
-      headers: {},
-      release_date: "2023-04-01",
-    })
+      {},
+    )
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toEqual([
@@ -319,38 +323,42 @@ describe("ProviderTransform.message - DeepSeek reasoning content", () => {
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, {
-      id: "openai/gpt-4",
-      providerID: "openai",
-      api: {
-        id: "gpt-4",
-        url: "https://api.openai.com",
-        npm: "@ai-sdk/openai",
+    const result = ProviderTransform.message(
+      msgs,
+      {
+        id: "openai/gpt-4",
+        providerID: "openai",
+        api: {
+          id: "gpt-4",
+          url: "https://api.openai.com",
+          npm: "@ai-sdk/openai",
+        },
+        name: "GPT-4",
+        capabilities: {
+          temperature: true,
+          reasoning: false,
+          attachment: true,
+          toolcall: true,
+          input: { text: true, audio: false, image: true, video: false, pdf: false },
+          output: { text: true, audio: false, image: false, video: false, pdf: false },
+          interleaved: false,
+        },
+        cost: {
+          input: 0.03,
+          output: 0.06,
+          cache: { read: 0.001, write: 0.002 },
+        },
+        limit: {
+          context: 128000,
+          output: 4096,
+        },
+        status: "active",
+        options: {},
+        headers: {},
+        release_date: "2023-04-01",
       },
-      name: "GPT-4",
-      capabilities: {
-        temperature: true,
-        reasoning: false,
-        attachment: true,
-        toolcall: true,
-        input: { text: true, audio: false, image: true, video: false, pdf: false },
-        output: { text: true, audio: false, image: false, video: false, pdf: false },
-        interleaved: false,
-      },
-      cost: {
-        input: 0.03,
-        output: 0.06,
-        cache: { read: 0.001, write: 0.002 },
-      },
-      limit: {
-        context: 128000,
-        output: 4096,
-      },
-      status: "active",
-      options: {},
-      headers: {},
-      release_date: "2023-04-01",
-    })
+      {},
+    )
 
     expect(result[0].content).toEqual([
       { type: "reasoning", text: "Should not be processed" },
@@ -404,7 +412,7 @@ describe("ProviderTransform.message - empty image handling", () => {
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, mockModel)
+    const result = ProviderTransform.message(msgs, mockModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(2)
@@ -428,7 +436,7 @@ describe("ProviderTransform.message - empty image handling", () => {
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, mockModel)
+    const result = ProviderTransform.message(msgs, mockModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(2)
@@ -450,7 +458,7 @@ describe("ProviderTransform.message - empty image handling", () => {
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, mockModel)
+    const result = ProviderTransform.message(msgs, mockModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(3)
@@ -503,7 +511,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       { role: "user", content: "World" },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(2)
     expect(result[0].content).toBe("Hello")
@@ -522,7 +530,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(1)
@@ -541,7 +549,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(1)
@@ -561,7 +569,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       { role: "user", content: "World" },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(2)
     expect(result[0].content).toBe("Hello")
@@ -579,7 +587,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(1)
@@ -603,7 +611,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, anthropicModel)
+    const result = ProviderTransform.message(msgs, anthropicModel, {})
 
     expect(result).toHaveLength(1)
     expect(result[0].content).toHaveLength(2)
@@ -630,7 +638,7 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       },
     ] as any[]
 
-    const result = ProviderTransform.message(msgs, openaiModel)
+    const result = ProviderTransform.message(msgs, openaiModel, {})
 
     expect(result).toHaveLength(2)
     expect(result[0].content).toBe("")
@@ -638,6 +646,189 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
   })
 })
 
+describe("ProviderTransform.message - strip openai metadata when store=false", () => {
+  const openaiModel = {
+    id: "openai/gpt-5",
+    providerID: "openai",
+    api: {
+      id: "gpt-5",
+      url: "https://api.openai.com",
+      npm: "@ai-sdk/openai",
+    },
+    name: "GPT-5",
+    capabilities: {
+      temperature: true,
+      reasoning: true,
+      attachment: true,
+      toolcall: true,
+      input: { text: true, audio: false, image: true, video: false, pdf: false },
+      output: { text: true, audio: false, image: false, video: false, pdf: false },
+      interleaved: false,
+    },
+    cost: { input: 0.03, output: 0.06, cache: { read: 0.001, write: 0.002 } },
+    limit: { context: 128000, output: 4096 },
+    status: "active",
+    options: {},
+    headers: {},
+  } as any
+
+  test("strips itemId and reasoningEncryptedContent when store=false", () => {
+    const msgs = [
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "reasoning",
+            text: "thinking...",
+            providerOptions: {
+              openai: {
+                itemId: "rs_123",
+                reasoningEncryptedContent: "encrypted",
+              },
+            },
+          },
+          {
+            type: "text",
+            text: "Hello",
+            providerOptions: {
+              openai: {
+                itemId: "msg_456",
+              },
+            },
+          },
+        ],
+      },
+    ] as any[]
+
+    const result = ProviderTransform.message(msgs, openaiModel, { store: false }) as any[]
+
+    expect(result).toHaveLength(1)
+    expect(result[0].content[0].providerOptions?.openai?.itemId).toBeUndefined()
+    expect(result[0].content[0].providerOptions?.openai?.reasoningEncryptedContent).toBeUndefined()
+    expect(result[0].content[1].providerOptions?.openai?.itemId).toBeUndefined()
+  })
+
+  test("strips itemId and reasoningEncryptedContent when store=false even when not openai", () => {
+    const zenModel = {
+      ...openaiModel,
+      providerID: "zen",
+    }
+    const msgs = [
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "reasoning",
+            text: "thinking...",
+            providerOptions: {
+              openai: {
+                itemId: "rs_123",
+                reasoningEncryptedContent: "encrypted",
+              },
+            },
+          },
+          {
+            type: "text",
+            text: "Hello",
+            providerOptions: {
+              openai: {
+                itemId: "msg_456",
+              },
+            },
+          },
+        ],
+      },
+    ] as any[]
+
+    const result = ProviderTransform.message(msgs, zenModel, { store: false }) as any[]
+
+    expect(result).toHaveLength(1)
+    expect(result[0].content[0].providerOptions?.openai?.itemId).toBeUndefined()
+    expect(result[0].content[0].providerOptions?.openai?.reasoningEncryptedContent).toBeUndefined()
+    expect(result[0].content[1].providerOptions?.openai?.itemId).toBeUndefined()
+  })
+
+  test("preserves other openai options when stripping itemId", () => {
+    const msgs = [
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "text",
+            text: "Hello",
+            providerOptions: {
+              openai: {
+                itemId: "msg_123",
+                otherOption: "value",
+              },
+            },
+          },
+        ],
+      },
+    ] as any[]
+
+    const result = ProviderTransform.message(msgs, openaiModel, { store: false }) as any[]
+
+    expect(result[0].content[0].providerOptions?.openai?.itemId).toBeUndefined()
+    expect(result[0].content[0].providerOptions?.openai?.otherOption).toBe("value")
+  })
+
+  test("does not strip metadata when store is not false", () => {
+    const msgs = [
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "text",
+            text: "Hello",
+            providerOptions: {
+              openai: {
+                itemId: "msg_123",
+              },
+            },
+          },
+        ],
+      },
+    ] as any[]
+
+    const result = ProviderTransform.message(msgs, openaiModel, { store: true }) as any[]
+
+    expect(result[0].content[0].providerOptions?.openai?.itemId).toBe("msg_123")
+  })
+
+  test("does not strip metadata for non-openai packages", () => {
+    const anthropicModel = {
+      ...openaiModel,
+      providerID: "anthropic",
+      api: {
+        id: "claude-3",
+        url: "https://api.anthropic.com",
+        npm: "@ai-sdk/anthropic",
+      },
+    }
+    const msgs = [
+      {
+        role: "assistant",
+        content: [
+          {
+            type: "text",
+            text: "Hello",
+            providerOptions: {
+              openai: {
+                itemId: "msg_123",
+              },
+            },
+          },
+        ],
+      },
+    ] as any[]
+
+    const result = ProviderTransform.message(msgs, anthropicModel, { store: false }) as any[]
+
+    expect(result[0].content[0].providerOptions?.openai?.itemId).toBe("msg_123")
+  })
+})
+
 describe("ProviderTransform.variants", () => {
   const createMockModel = (overrides: Partial<any> = {}): any => ({
     id: "test/test-model",