Rust API Test Harness

What it does

When your agent uses it

• Debugging Rust HTTP APIs and services
• Especially when Codex needs black-box integration tests
• Random-port app startup
• Real database test isolation

Example prompts

• “/rust-api-test-harness”

Requirements

• A Bash shell
• Docker
• Compatibility (from SKILL.md): Codex, Claude Code, and other Agent Skills-compatible clients.

Workflow steps

8 steps, taken from the first numbered list in SKILL.md.

1. 1Inspect the project first: Cargo.toml, workspace layout, existing src/main.rs,
2. 2Find the application boundary. Extract startup code into a reusable function
3. 3Write or update an integration test before changing behavior. Put API tests
4. 4Create a spawn_app helper that starts the service once per test case,
5. 5Exercise the public HTTP contract with reqwest, not framework-specific
6. 6Isolate state. Use real dependencies when behavior depends on their semantics
7. 7Keep test helpers as production-quality code. Give failures useful messages,
8. 8Run the local verification script or equivalent cargo commands before

What it can do on your machine

Read from SKILL.md and the folder at commit 78497e5. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 1 file in scripts/ (Shell), which the agent can run.

  Shell commands in SKILL.md call:

  • cargo

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Codex, Claude Code, and other Agent Skills-compatible clients.

  From compatibility in the SKILL.md frontmatter.

Context cost

Rust API Test Harness loads about 1.7k tokens when it runs, and up to ~2.9k if it reads all its reference files. Until then it costs about 82 tokens; SKILL.md has 579 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~82

When it runs · the whole SKILL.md, loaded when a task matches

~1.7k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from hashgraph-online/awesome-codex-plugins at commit 78497e5, republished under its MIT licence (© hashgraph-online). 579 words, ~1,712 tokens.

name

rust-api-test-harness

description

Use when adding, changing, testing, or debugging Rust HTTP APIs and services, especially when Codex needs black-box integration tests, random-port app startup, real database test isolation, external HTTP mocks, or CI-ready cargo verification for Actix, Axum, Warp, Rocket, or similar Rust web frameworks.

compatibility

Codex, Claude Code, and other Agent Skills-compatible clients.

license

MIT

metadata.version

0.1.0

metadata.displayName

Rust API Test Harness

metadata.category

Rust

metadata.tags

rust,api-testing,integration-tests,backend

pub fn run(
    listener: std::net::TcpListener,
    app_state: AppState,
) -> Result<actix_web::dev::Server, std::io::Error> {
    let state = actix_web::web::Data::new(app_state);
    let server = actix_web::HttpServer::new(move || {
        actix_web::App::new()
            .app_data(state.clone())
            .route("/health_check", actix_web::web::get().to(health_check))
    })
    .listen(listener)?
    .run();

    Ok(server)
}

pub fn router(app_state: AppState) -> axum::Router {
    axum::Router::new()
        .route("/health_check", axum::routing::get(health_check))
        .with_state(app_state)
}

pub async fn spawn_axum_app() -> TestApp {
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
        .await
        .expect("failed to bind random port");
    let port = listener.local_addr().unwrap().port();
    let server = axum::serve(listener, router(test_state().await));
    let server_handle = tokio::spawn(async move { server.await });

    TestApp {
        address: format!("http://127.0.0.1:{port}"),
        http_client: reqwest::Client::new(),
        server_handle,
    }
}

pub struct TestApp {
    pub address: String,
    pub http_client: reqwest::Client,
    pub server_handle: tokio::task::JoinHandle<std::io::Result<()>>,
}

pub async fn spawn_app() -> TestApp {
    let listener = std::net::TcpListener::bind("127.0.0.1:0")
        .expect("failed to bind random port");
    let port = listener.local_addr().unwrap().port();

    let server = my_app::startup::run(listener, test_state().await)
        .expect("failed to start test server");
    let server_handle = tokio::spawn(server);

    TestApp {
        address: format!("http://127.0.0.1:{port}"),
        http_client: reqwest::Client::new(),
        server_handle,
    }
}

path/to/rust-api-test-harness/scripts/check-rust-service.sh

cargo fmt --all --check
cargo clippy --all-targets --all-features -- -D warnings
cargo test --all-features

© hashgraph-online, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 5 other files (scripts, references, assets) in plugins/LVTD-LLC/skills/skills/rust-api-test-harness of hashgraph-online/awesome-codex-plugins.

• SKILL.md
• agents/openai.yaml
• assets/app-icon.png
• references/database-test-isolation.md
• references/external-http-mocks.md
• scripts/check-rust-service.sh

Open the folder on GitHubat commit 78497e5