diff --git a/open-sse/executors/opencode.ts b/open-sse/executors/opencode.ts
index 51a04728..99a591d7 100644
--- a/open-sse/executors/opencode.ts
+++ b/open-sse/executors/opencode.ts
@@ -45,7 +45,11 @@ export class OpencodeExecutor extends BaseExecutor {
     const key = credentials?.apiKey || credentials?.accessToken;
 
     if (key) {
-      headers["Authorization"] = `Bearer ${key}`;
+      if (this._requestFormat === "claude") {
+        headers["x-api-key"] = key;
+      } else {
+        headers["Authorization"] = `Bearer ${key}`;
+      }
     }
 
     if (this._requestFormat === "claude") {
diff --git a/tests/unit/opencode-executor.test.mjs b/tests/unit/opencode-executor.test.mjs
index 11710961..8859eb64 100644
--- a/tests/unit/opencode-executor.test.mjs
+++ b/tests/unit/opencode-executor.test.mjs
@@ -158,7 +158,7 @@ describe("OpencodeExecutor", () => {
       );
 
       assert.deepEqual(result.headers, {
-        Authorization: "Bearer claude-key",
+        "x-api-key": "claude-key",
         "Content-Type": "application/json",
         "anthropic-version": "2023-06-01",
         Accept: "text/event-stream",