Quick start

You’ll end up with Google’s Rust style guide enforced by your formatter, linter and dependency checker, plus instructions your coding agent reads automatically. It takes about five minutes.

Before you start

You need Rust 1.95 or newer on the stable channel (rustup update stable) and an existing Cargo project. Nothing here changes your code; it only adds config files.

Do it yourself

1. Add the config files (30 seconds)

   Run this from your project root. Files you already have are skipped, never overwritten.

   Terminal

   base=https://daniakash.github.io/Google-Rust-Style-Guide/files
   for f in rustfmt.toml clippy.toml deny.toml rust-toolchain.toml AGENTS.md; do
     if [ -e "$f" ]; then echo "skipped $f (already exists)"; else curl -fsSLO "$base/$f"; fi
   done

   • Directoryyour-project/

     • AGENTS.md instructions for coding agents
     • clippy.toml lint thresholds and banned APIs
     • deny.toml bans crates that run code before main()
     • rust-toolchain.toml pins the stable channel
     • rustfmt.toml the guide’s formatting options
     • Cargo.toml
     • Directorysrc/

       • …

2. Turn on the lints (1 minute)

   Pick your project shape. Your choice is remembered on every page.

   Single crate

   Single crate: append the lint tables to your Cargo.toml.

   Terminal

   curl -fsSL https://daniakash.github.io/Google-Rust-Style-Guide/files/crate-lints.toml >> Cargo.toml

   See exactly what gets added on the Cargo.toml lints page.

   Workspace

   Workspace: append the lint tables to your workspace root Cargo.toml.

   Terminal

   curl -fsSL https://daniakash.github.io/Google-Rust-Style-Guide/files/workspace-lints.toml >> Cargo.toml

   Then opt every member crate in by adding these two lines to its Cargo.toml:

   crates/<member>/Cargo.toml

   [lints]
   workspace = true

   Or do all members at once:

   Terminal

   # Run from the workspace root. Adjust crates/* to where your members live.
   for member in crates/*/Cargo.toml; do
     printf '\n[lints]\nworkspace = true\n' >> "$member"
   done

   See exactly what gets added on the Cargo.toml lints page.

   Caution

   If your Cargo.toml already has a [lints] or [workspace.lints] table, Cargo will report a duplicate key. Merge the tables by hand instead of appending.

3. Point your coding agent at it (10 seconds)

   Codex, Cursor, Gemini CLI, GitHub Copilot and most other agents read AGENTS.md automatically. Claude Code reads CLAUDE.md, so link it:

   Terminal

   ln -s AGENTS.md CLAUDE.md

   If step 1 skipped AGENTS.md because you already have one, paste the kit’s AGENTS.md into it as a “Rust style” section.

4. Verify (2 minutes)

   Install nightly rustfmt (for three of the guide’s formatting options) and cargo-deny once:

   Terminal (one time)

   rustup toolchain install nightly --profile minimal --component rustfmt
   cargo install --locked cargo-deny

   Then run the three checks:

   Terminal

   cargo +nightly fmt
   cargo clippy --workspace --all-targets -- -D warnings
   cargo deny check bans

   Expect a few errors on a brand-new project. -D warnings turns every lint warning into an error, which is the kit doing its job. A fresh cargo new --lib reports three:

   cargo clippy output

   error: this function could have a `#[must_use]` attribute
   error: missing documentation for the crate
   error: missing documentation for a function

   Fixing them takes three lines (a binary crate only needs the //! line in src/main.rs):

   src/lib.rs

   //! Adds numbers.
   
   /// Returns the sum of `left` and `right`.
   #[must_use]
   pub fn add(left: u64, right: u64) -> u64 {
       left + right
   }

   When everything is green you’ll see:

   Terminal

       Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.03s
   bans ok

Let your agent do it

Paste this into Claude Code, Codex, Cursor or any coding agent that can run commands:

Prompt

Apply the Google Rust Style Guide kit to this repository.
Follow the instructions at
https://daniakash.github.io/Google-Rust-Style-Guide/_llms-txt/for-coding-agents.txt
Then run cargo +nightly fmt, cargo clippy --workspace --all-targets -- -D warnings,
and cargo deny check bans, and fix what they report without editing the lint configuration.

The linked file bundles this quick start, the kit’s AGENTS.md, the adoption guide and an explanation of each config file, so the agent learns the whole setup in one request and then downloads the files themselves.

Review the diff

Agents sometimes silence a warning by editing the lint configuration. The kit’s AGENTS.md forbids that, but check that Cargo.toml lint tables, clippy.toml, rustfmt.toml and deny.toml match the downloaded versions.

Add it to CI

Make warnings block merges by running the same checks in CI with -D warnings:

.github/workflows/style.yml

name: Style
on: [push, pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: cargo clippy --workspace --all-targets -- -D warnings

  format:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: rustup toolchain install nightly --profile minimal --component rustfmt
      - run: cargo +nightly fmt --check

  deny:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: taiki-e/install-action@v2
        with:
          tool: cargo-deny
      - run: cargo deny check bans

Troubleshooting

You see	Why	Do this
Warning: can't set `hex_literal_case = Lower`, unstable features are only available in nightly channel.	Three of the guide’s rustfmt options only exist on nightly rustfmt	Run cargo +nightly fmt. On stable the warning is harmless and the other options still apply.
unknown lint: `clippy::...`	Your toolchain is older than the kit’s tested Rust 1.95	rustup update stable
cannot override `workspace.lints` in `lints`	A member crate has both [lints] workspace = true and its own [lints.*] tables	Keep workspace = true and relax a lint at the crate root instead: #![expect(clippy::lint_name, reason = "...")]
duplicate key in Cargo.toml	Your Cargo.toml already had lint tables	Merge the appended tables into the existing ones by hand
error: no such command: `deny`	cargo-deny is a separate tool	cargo install --locked cargo-deny (or brew install cargo-deny)
use of a disallowed type `std::sync::Arc`	The guide asks you to justify shared ownership	Restructure to a single owner, or add #[expect(clippy::disallowed_types, reason = "...")] with the reason
Hundreds of warnings	Your codebase predates the kit	Follow the phased rollout for existing codebases

Remove the kit

Changed your mind? If you added the kit in its own commit, reverting that commit is the cleanest way out. Otherwise, run this from your project root. It only deletes files that are still identical to the kit’s versions, so your own config files and any you edited are kept:

Terminal

base=https://daniakash.github.io/Google-Rust-Style-Guide/files
for f in rustfmt.toml clippy.toml deny.toml rust-toolchain.toml AGENTS.md; do
  if [ -f "$f" ] && curl -fsSL "$base/$f" | cmp -s - "$f"; then rm "$f"; echo "removed $f"
  elif [ -e "$f" ]; then echo "kept $f (not the kit's version)"; fi
done
if [ -L CLAUDE.md ] && [ "$(readlink CLAUDE.md)" = AGENTS.md ] && [ ! -e AGENTS.md ]; then rm CLAUDE.md; fi

Then finish by hand:

• In Cargo.toml, delete everything from the # Google Rust Style Guide lints comment to the end of the file, and remove [lints] workspace = true from member crates if you added it.
• If you pasted the kit’s rules into an existing AGENTS.md instead of downloading it, delete that section.
• Files reported as “kept” are either yours or edited since you downloaded them. Remove them only if you are sure.

Next steps

How it worksThe three enforcement layers and how exceptions are recorded.

Human review guideWhat reviewers still need to check once CI is green.

CoverageEvery guide rule and the check that enforces it.

Adopting in depthExisting codebases, published libraries and application crates.