Report · marked 10 Oct 2026

rust-lang/rustlings

An agent can work here, but it will waste turns finding its footing.

Rust · 64,312 stars · 293 files · branch main

57 /100 B-

Instructions 1/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on agent instruction file and instruction quality.Setup 6/14Whether an agent can install the project and get it running without a human. Losing marks on discoverable commands and pinned runtime version.Verification loop 18/22Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy. Losing marks on tests exist.Context economy 20/20Whether the repo fits in a context window, or fights it. Full marks.Navigability 8/10How quickly anything new can orient itself. Losing marks on written documentation.

Higher is better. Accent marks what is costing you most.

Fix these first

Agent instruction file

Add an AGENTS.md at the root: what the project is, how to install, how to run, how to test, and the two or three conventions a newcomer always gets wrong.

Instruction quality

Instructions earn their keep by naming exact commands. 'Run the tests with `pnpm test`' beats three paragraphs of philosophy.

Discoverable commands

Declare the handful of commands that matter in package.json scripts, a Makefile, or a justfile. Naming them turns guesswork into a lookup.

The full marking

Every deduction below names the file or setting it came from.

Instructions 1/27 F

Whether the repo tells an agent how to behave before it starts guessing.

✗Agent instruction file 0/12

None found. Every agent that opens this repo starts from zero.

Add an AGENTS.md at the root: what the project is, how to install, how to run, how to test, and the two or three conventions a newcomer always gets wrong.

Looked for AGENTS.md, CLAUDE.md, .github/copilot-instructions.md, .cursorrules

✗Instruction quality 0/12

Nothing to judge, since there are no instructions.

Instructions earn their keep by naming exact commands. 'Run the tests with `pnpm test`' beats three paragraphs of philosophy.

✗README as an entry point 1/3

README exists but never explains how to get the thing running.

Give the README an Install and a Usage heading with real commands under each. Agents pattern-match on those headings.

Setup 6/14 C

Whether an agent can install the project and get it running without a human.

✓Deterministic install 6/6

cargo.lock pins the dependency tree.

Found cargo.lock

✗Discoverable commands 0/6

No declared commands. An agent has to infer how to build and run this from the file tree.

Declare the handful of commands that matter in package.json scripts, a Makefile, or a justfile. Naming them turns guesswork into a lookup.

–Environment config n/a

Not applicable — this reads as a library, with no environment to configure.

✗Pinned runtime version 0/2

No pinned runtime version.

Add a .nvmrc, .python-version, or equivalent so the agent's toolchain matches yours.

–Reproducible environment n/a

Not applicable — a library doesn't need a container to be worked on.

Verification loop 18/22 A-

Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy.

✗Tests exist 4/8

8 test files against 223 source files.

Coverage is thin enough that an agent can break real behavior and still see green.

e.g. tests/integration_tests.rs, tests/test_exercises/dev/Cargo.toml, tests/test_exercises/exercises/compilation_failure.rs

✓Test command is discoverable 7/7

An agent can find and run `cargo test`.

✓Continuous integration 4/4

2 GitHub Actions workflows define what "passing" means.

✓Lint and format rules 3/3

clippy.toml encodes the house style.

–Static type checking n/a

Not applicable — the Rust compiler type checks every build.

Context economy 20/20 A+

Whether the repo fits in a context window, or fights it.

✓No committed build output 6/6

No generated directories committed.

✓.gitignore hygiene 3/3

.gitignore covers 10 patterns.

✓File sizes fit in context 6/6

No source file is large enough to crowd out a context window.

✓Repository weight 5/5

About 4.5MB checked out, which is comfortable.

Here is your AGENTS.md

Drafted from what is actually in this repository: the install command from your lockfile, the commands you already declare, your real directory layout. Anything marked TODO needs a person. Save it at the root as AGENTS.md.

AGENTS.md — drafted for rust-lang/rustlings

# AGENTS.md

:crab: Small exercises to get you used to reading and writing Rust code!

## Setup

```
cargo build
```

## Commands

```
cargo test   # run the test suite
```

## Layout

- `exercises/`        95 source files
- `solutions/`        95 source files
- `src/`              24 source files
- `tests/`            6 source files
- `rustlings-macros/` 1 source file

## Conventions

- Tests live alongside the code they cover, following `tests/integration_tests.rs`.
- CI defines what passing means. See `.github/workflows/rust.yml`, and keep it green.
- TODO: add the two or three conventions a newcomer always gets wrong here.

---

Drafted by agentreadme.com from what is in this repository. Everything marked TODO
needs a human. Check it in as AGENTS.md at the root.

Open the raw markdown or curl -o AGENTS.md agentreadme.com/draft/rust-lang/rustlings.md

A draft gets the commands right and stops at the things only a maintainer knows. What a good Rust AGENTS.md looks like covers what to add by hand, and what AGENTS.md is explains the format itself.

Show the mark

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[![agent ready](https://agentreadme.com/badge/rust-lang/rustlings.svg)](https://agentreadme.com/rust-lang/rustlings)

Other Rust repositories, marked

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All Rust repositories

Think this mark is wrong?

Every deduction above names the file it came from, so this can be settled by looking. If a check missed something, that is a rule worth fixing.

Open an issue, already filled in