codex/codex-rs/core/tests/suite/hierarchical_agents.rs

use codex_features::Feature;
use core_test_support::responses::ev_completed;
use core_test_support::responses::ev_response_created;
use core_test_support::responses::mount_sse_once;
use core_test_support::responses::sse;
use core_test_support::responses::start_mock_server;
use core_test_support::test_codex::test_codex;

const HIERARCHICAL_AGENTS_SNIPPET: &str =
    "Files called AGENTS.md commonly appear in many places inside a container";

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn hierarchical_agents_appends_to_project_doc_in_user_instructions() {
    let server = start_mock_server().await;
    let resp_mock = mount_sse_once(
        &server,
        sse(vec![ev_response_created("resp1"), ev_completed("resp1")]),
    )
    .await;

    let mut builder = test_codex()
        .with_config(|config| {
            config
                .features
                .enable(Feature::ChildAgentsMd)
                .expect("test config should allow feature update");
        })
        .with_workspace_setup(|cwd, fs| async move {
            let agents_md = cwd.join("AGENTS.md").expect("absolute AGENTS.md path");
            fs.write_file(&agents_md, b"be nice".to_vec()).await?;
            Ok::<(), anyhow::Error>(())
        });
    let test = builder
        .build_remote_aware(&server)
        .await
        .expect("build test codex");

    test.submit_turn("hello").await.expect("submit turn");

    let request = resp_mock.single_request();
    let user_messages = request.message_input_texts("user");
    let instructions = user_messages
        .iter()
        .find(|text| text.starts_with("# AGENTS.md instructions for "))
        .expect("instructions message");
    assert!(
        instructions.contains("be nice"),
        "expected AGENTS.md text included: {instructions}"
    );
    let snippet_pos = instructions
        .find(HIERARCHICAL_AGENTS_SNIPPET)
        .expect("expected hierarchical agents snippet");
    let base_pos = instructions
        .find("be nice")
        .expect("expected AGENTS.md text");
    assert!(
        snippet_pos > base_pos,
        "expected hierarchical agents message appended after base instructions: {instructions}"
    );
}

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn hierarchical_agents_emits_when_no_project_doc() {
    let server = start_mock_server().await;
    let resp_mock = mount_sse_once(
        &server,
        sse(vec![ev_response_created("resp1"), ev_completed("resp1")]),
    )
    .await;

    let mut builder = test_codex().with_config(|config| {
        config
            .features
            .enable(Feature::ChildAgentsMd)
            .expect("test config should allow feature update");
    });
    let test = builder
        .build_remote_aware(&server)
        .await
        .expect("build test codex");

    test.submit_turn("hello").await.expect("submit turn");

    let request = resp_mock.single_request();
    let user_messages = request.message_input_texts("user");
    let instructions = user_messages
        .iter()
        .find(|text| text.starts_with("# AGENTS.md instructions for "))
        .expect("instructions message");
    assert!(
        instructions.contains(HIERARCHICAL_AGENTS_SNIPPET),
        "expected hierarchical agents message appended: {instructions}"
    );
}