feat: dynamically resolve AGENTS.md files from subdirectories as agent explores them (#10678)

packages/opencode/test/tool/read.test.ts

@@ -14,6 +14,7 @@ const ctx = {
   callID: "",
   agent: "build",
   abort: AbortSignal.any([]),
+  messages: [],
   metadata: () => {},
   ask: async () => {},
 }
@@ -330,3 +331,26 @@ root_type Monster;`
     })
   })
 })
+
+describe("tool.read loaded instructions", () => {
+  test("loads AGENTS.md from parent directory and includes in metadata", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(path.join(dir, "subdir", "AGENTS.md"), "# Test Instructions\nDo something special.")
+        await Bun.write(path.join(dir, "subdir", "nested", "test.txt"), "test content")
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "subdir", "nested", "test.txt") }, ctx)
+        expect(result.output).toContain("test content")
+        expect(result.output).toContain("system-reminder")
+        expect(result.output).toContain("Test Instructions")
+        expect(result.metadata.loaded).toBeDefined()
+        expect(result.metadata.loaded).toContain(path.join(tmp.path, "subdir", "AGENTS.md"))
+      },
+    })
+  })
+})