diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index f22e2543f9d9..c791aebf9713 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -230,18 +230,6 @@ function normalizeMessages(
       const parts = msg.content
       const first = parts.findIndex((part) => part.type === "tool-call")
       if (first === -1) return [msg]
-      // Anthropic signs thinking blocks, so moving them during replay invalidates the request.
-      if (
-        parts
-          .slice(first)
-          .some(
-            (part) =>
-              part.type === "reasoning" &&
-              (part.providerOptions?.anthropic?.signature != null ||
-                part.providerOptions?.anthropic?.redactedData != null),
-          )
-      )
-        return [msg]
       if (!parts.slice(first).some((part) => part.type !== "tool-call")) return [msg]
       return [
         { ...msg, content: parts.filter((part) => part.type !== "tool-call") },
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 26c45f619413..7fb22ddf5770 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -1680,25 +1680,6 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
     ])
   })
 
-  test("leaves signed anthropic reasoning after tool calls unchanged", () => {
-    const msgs = [
-      {
-        role: "assistant",
-        content: [
-          { type: "reasoning", text: "First thought", providerOptions: { anthropic: { signature: "sig-1" } } },
-          { type: "tool-call", toolCallId: "toolu_1", toolName: "read", input: { filePath: "/root" } },
-          { type: "reasoning", text: "Second thought", providerOptions: { anthropic: { signature: "sig-2" } } },
-          { type: "tool-call", toolCallId: "toolu_2", toolName: "glob", input: { pattern: "**/*.pdf" } },
-        ],
-      },
-    ] as any[]
-
-    const result = ProviderTransform.message(msgs, anthropicModel, {}) as any[]
-
-    expect(result).toHaveLength(1)
-    expect(result[0].content).toMatchObject(msgs[0].content)
-  })
-
   test("splits vertex anthropic assistant messages when text trails tool calls", () => {
     const model = {
       ...anthropicModel,
@@ -1736,34 +1717,6 @@ describe("ProviderTransform.message - anthropic empty content filtering", () =>
       ],
     })
   })
-
-  test("leaves redacted vertex anthropic reasoning after tool calls unchanged", () => {
-    const model = {
-      ...anthropicModel,
-      providerID: "google-vertex-anthropic",
-      api: {
-        id: "claude-sonnet-4@20250514",
-        url: "https://us-central1-aiplatform.googleapis.com",
-        npm: "@ai-sdk/google-vertex/anthropic",
-      },
-    }
-
-    const msgs = [
-      {
-        role: "assistant",
-        content: [
-          { type: "tool-call", toolCallId: "toolu_1", toolName: "read", input: { filePath: "/root" } },
-          { type: "reasoning", text: "", providerOptions: { anthropic: { redactedData: "redacted-1" } } },
-          { type: "tool-call", toolCallId: "toolu_2", toolName: "glob", input: { pattern: "**/*.pdf" } },
-        ],
-      },
-    ] as any[]
-
-    const result = ProviderTransform.message(msgs, model, {}) as any[]
-
-    expect(result).toHaveLength(1)
-    expect(result[0].content).toMatchObject(msgs[0].content)
-  })
 })
 
 describe("ProviderTransform.message - strip openai metadata when store=false", () => {