diff --git a/packages/opencode/src/plugin/github-copilot/copilot.ts b/packages/opencode/src/plugin/github-copilot/copilot.ts
index 9c744db89b..161bf859f7 100644
--- a/packages/opencode/src/plugin/github-copilot/copilot.ts
+++ b/packages/opencode/src/plugin/github-copilot/copilot.ts
@@ -361,6 +361,7 @@ export async function CopilotAuthPlugin(input: PluginInput): Promise<Hooks> {
       if (!incoming.model.providerID.includes("github-copilot")) return
 
       output.headers["X-GitHub-Api-Version"] = API_VERSION
+      output.headers["X-Interaction-Id"] = incoming.sessionID
       if (incoming.agent === "title") {
         output.headers["X-Interaction-Type"] = "agent-session-name-generation"
       }
diff --git a/packages/opencode/test/plugin/github-copilot.test.ts b/packages/opencode/test/plugin/github-copilot.test.ts
new file mode 100644
index 0000000000..cd1864b795
--- /dev/null
+++ b/packages/opencode/test/plugin/github-copilot.test.ts
@@ -0,0 +1,56 @@
+import { expect, test } from "bun:test"
+import type { Hooks } from "@opencode-ai/plugin"
+import { CopilotAuthPlugin } from "@/plugin/github-copilot/copilot"
+
+type ChatHeaders = NonNullable<Hooks["chat.headers"]>
+
+async function hook() {
+  const hooks = await CopilotAuthPlugin({
+    directory: "",
+    project: {} as never,
+    worktree: "",
+    experimental_workspace: { register() {} },
+    serverUrl: new URL("http://localhost"),
+    $: {} as never,
+    client: {
+      session: {
+        message: async () => ({ data: { parts: [] } }),
+        get: async () => ({ data: {} }),
+      },
+    } as never,
+  })
+  return hooks["chat.headers"]!
+}
+
+function input(sessionID: string, providerID: string, npm: string) {
+  return {
+    sessionID,
+    agent: "build",
+    model: { providerID, api: { npm } },
+    message: { id: "msg_test", sessionID },
+  } as Parameters<ChatHeaders>[0]
+}
+
+test.each([
+  ["github-copilot", "@ai-sdk/github-copilot"],
+  ["github-copilot", "@ai-sdk/anthropic"],
+  ["github-copilot-enterprise", "@ai-sdk/github-copilot"],
+  ["github-copilot-enterprise", "@ai-sdk/anthropic"],
+])("uses the session ID for %s interaction headers with %s", async (providerID, npm) => {
+  const headers = await hook()
+  for (const sessionID of ["ses_one", "ses_one", "ses_two"]) {
+    const output = { headers: { "x-existing": "preserved" } }
+    await headers(input(sessionID, providerID, npm), output)
+    expect(output.headers).toMatchObject({
+      "X-Interaction-Id": sessionID,
+      "x-existing": "preserved",
+    })
+  }
+})
+
+test("does not add interaction headers to other providers", async () => {
+  const headers = await hook()
+  const output = { headers: { "x-existing": "preserved" } }
+  await headers(input("ses_one", "openai", "@ai-sdk/openai"), output)
+  expect(output.headers).toEqual({ "x-existing": "preserved" })
+})