Report · marked 25 Aug 2026

google/zx

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

JavaScript · 45,703 stars · 180 files · branch main

66 /100 B

Instructions 3/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on agent instruction file and instruction quality.Setup 14/14Whether an agent can install the project and get it running without a human. Full marks.Verification loop 22/25Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy. Losing marks on lint and format rules.Context economy 14/20Whether the repo fits in a context window, or fights it. Losing marks on file sizes fit in context.Navigability 10/10How quickly anything new can orient itself. Full marks.

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.

File sizes fit in context

A single file that fills the context window forces an agent to work from fragments, and it will confidently edit code it never saw. Splitting the worst offenders pays for itself immediately.

The full marking

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

Instructions 3/27 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 3/3

README has a clear getting-started section.

Setup 14/14 A+

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

✓Deterministic install 6/6

package-lock.json pins the dependency tree.

Found package-lock.json

✓Discoverable commands 6/6

Commands are declared where an agent will look for them.

package.json scripts (fmt, fmt:check, prebuild, build, build:js, build:vendor…)

scripts/ directory

–Environment config n/a

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

✓Pinned runtime version 2/2

The language runtime version is pinned.

package.json engines.node >= 12.17.0

–Reproducible environment n/a

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

Verification loop 22/25 A

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

✓Tests exist 8/8

45 test files against 106 source files.

e.g. test/all.test.js, test/bench/buf-join.mjs, test/cli.test.js

✓Test command is discoverable 7/7

An agent can find and run `npm run test`.

✓Continuous integration 4/4

8 GitHub Actions workflows define what "passing" means.

✗Lint and format rules 0/3

No linter or formatter config. Style is tribal knowledge, so agent output will drift from yours.

A formatter config is the cheapest way to stop reviewing whitespace in agent diffs. It moves style from opinion to a command.

✓Static type checking 3/3

Strict type checking is on, which catches a whole class of agent mistakes before they run.

Context economy 14/20 B+

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 13 patterns.

✗File sizes fit in context 0/6

1 source file is over 100KB.

A single file that fills the context window forces an agent to work from fragments, and it will confidently edit code it never saw. Splitting the worst offenders pays for itself immediately.

build/vendor-extra.cjs — 745KB

✓Repository weight 5/5

About 4.2MB 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 google/zx

# AGENTS.md

A tool for writing better scripts

## Setup

```
npm ci
```

## Commands

```
npm run build            # produce a build
npm run test             # run the test suite, must pass before any commit
npm run fmt
npm run fmt:check
npm run prebuild
npm run build:js
npm run build:vendor
npm run build:versions
```

## Layout

- `test/`     33 source files
- `build/`    31 source files
- `src/`      17 source files
- `scripts/`  12 source files
- `examples/` 7 source files
- `docs/`     3 source files

## Conventions

- Tests live alongside the code they cover, following `test/all.test.js`.
- TypeScript runs in strict mode. Type errors are the fastest feedback available, so do not weaken it.
- CI defines what passing means. See `.github/workflows/codeql.yml`, and keep it green.
- TODO: add the two or three conventions a newcomer always gets wrong here.

## Gotchas

- Generated output is committed (`build/`). Search will return the compiled copy, so edit the source, not that.
- `build/vendor-extra.cjs` is 745KB. It will not fit comfortably in context, so read it in parts.

---

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/google/zx.md

Show the mark

The badge re-checks daily, so it keeps up as the repository changes. Use mark again to force it now.

[![agent ready](https://agentreadme.com/badge/google/zx.svg)](https://agentreadme.com/google/zx)

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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.

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