diff --git a/tests/agent/fixtures.ts b/tests/agent/fixtures.ts
new file mode 100644
index 0000000..1d4694a
--- /dev/null
+++ b/tests/agent/fixtures.ts
@@ -0,0 +1,46 @@
+import { existsSync } from "node:fs";
+import { mkdir, writeFile, rm } from "node:fs/promises";
+import { join } from "node:path";
+import { runInit } from "../../src/commands/init.ts";
+import { loadConfig, getChangeDir } from "../../src/core/config.ts";
+import type { RuneConfig } from "../../src/types.ts";
+
+const TMP_DIR = join(import.meta.dir, "__tmp_agent_test__");
+
+export function getTempDir(): string {
+  return TMP_DIR;
+}
+
+export async function setupTempDir(): Promise<void> {
+  await rm(TMP_DIR, { recursive: true, force: true });
+  await mkdir(TMP_DIR, { recursive: true });
+}
+
+export async function cleanupTempDir(): Promise<void> {
+  await rm(TMP_DIR, { recursive: true, force: true });
+}
+
+export async function createFreshProject(editors: string[] = ["opencode"]): Promise<RuneConfig> {
+  await runInit(TMP_DIR, editors);
+  return loadConfig(TMP_DIR);
+}
+
+export async function createChangeDir(changeName: string): Promise<string> {
+  const dir = getChangeDir(TMP_DIR, changeName);
+  await mkdir(dir, { recursive: true });
+  return dir;
+}
+
+export async function writeDoc(
+  changeName: string,
+  docName: string,
+  content: string,
+): Promise<void> {
+  const dir = getChangeDir(TMP_DIR, changeName);
+  await mkdir(dir, { recursive: true });
+  await writeFile(join(dir, `${docName}.md`), content);
+}
+
+export function changeFileExists(changeName: string, fileName: string): boolean {
+  return existsSync(join(getChangeDir(TMP_DIR, changeName), fileName));
+}