Report · marked 10 Oct 2026

storybookjs/storybook

Solid foundations, held back in a few specific places.

TypeScript · 91,217 stars · 8,771 files · branch next

75 /100 B+

Instructions 25/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on instruction quality.Setup 14/20Whether an agent can install the project and get it running without a human. Losing marks on environment config and reproducible environment.Verification loop 19/25Whether 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 and static type checking.Context economy 9/20Whether the repo fits in a context window, or fights it. Losing marks on file sizes fit in context and repository weight.Navigability 10/10How quickly anything new can orient itself. Full marks.

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

Fix these first

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.

Environment config

Add a .env.example listing every variable with a safe placeholder value. It's the cheapest possible fix and it unblocks the whole first run.

Repository weight

Large binaries and vendored trees slow every operation an agent performs. Git LFS or a separate assets repo keeps the working tree navigable.

The full marking

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

Instructions 25/27 A+

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

✓Agent instruction file 12/12

AGENTS.md is present, which is the format the most tools read.

Also found: CLAUDE.md, .cursorrules

✗Instruction quality 10/12

Specific enough that an agent can act on it.

Worth fixing: has no code blocks.

3,387 characters, a workable length

names the actual commands to run

uses headings, so an agent can skim it

✓README as an entry point 3/3

README has a clear getting-started section.

Setup 14/20 B+

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

✓Deterministic install 6/6

yarn.lock pins the dependency tree.

Found yarn.lock

✓Discoverable commands 6/6

Commands are declared where an agent will look for them.

package.json scripts (ci-tests, docs:check, fmt:check, fmt:write, get-report-message, get-sandbox-dir…)

scripts/ directory

✗Environment config 0/4

Nothing documents the environment this needs. An agent will get a runtime error it can't diagnose.

Add a .env.example listing every variable with a safe placeholder value. It's the cheapest possible fix and it unblocks the whole first run.

✓Pinned runtime version 2/2

The language runtime version is pinned.

Found .nvmrc

✗Reproducible environment 0/2

No container or devcontainer definition.

A Dockerfile or devcontainer removes an entire class of 'it won't install' failures.

Verification loop 19/25 B+

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

✓Tests exist 8/8

1085 test files against 5520 source files.

e.g. .github/scripts/resolve-canary-ref.test.ts, .github/scripts/update-canary-pr-body-from-run.test.ts, agent-eval/lib/agentic-reference/collected-runs.test.ts

✓Test command is discoverable 7/7

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

✓Continuous integration 4/4

20 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 0/3

No static type checking.

A type checker gives an agent an error message instead of a runtime surprise. It's the second-fastest feedback loop after the compiler.

Context economy 9/20 C

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 80 patterns.

✗File sizes fit in context 0/6

5 source files are 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.

.yarn/releases/yarn-4.18.0.cjs — 3696KB

test-storybooks/ember-cli/ember-output/assets/vendor.js — 2140KB

code/core/src/manager/components/sidebar/mockdata.large.ts — 830KB

✗Repository weight 0/5

About 1128MB checked out. Large enough that cloning and searching are both slow.

Large binaries and vendored trees slow every operation an agent performs. Git LFS or a separate assets repo keeps the working tree navigable.

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 storybookjs/storybook

# AGENTS.md

Storybook is the industry standard workshop for building, documenting, and testing UI components in isolation

## Setup

```
yarn install
```

## Commands

```
yarn start                # run the app
yarn test                 # run the test suite, must pass before any commit
yarn lint                 # lint
yarn ci-tests
yarn docs:check
yarn fmt:check
yarn fmt:write
yarn get-report-message
```

## Layout

- `code/`            4850 source files
- `agent-eval/`      327 source files
- `scripts/`         188 source files
- `test-storybooks/` 141 source files
- `docs/`            1 source file

## Conventions

- Tests live alongside the code they cover, following `.github/scripts/resolve-canary-ref.test.ts`.
- CI defines what passing means. See `.github/workflows/agent-eval.yml`, and keep it green.
- TODO: add the two or three conventions a newcomer always gets wrong here.

## Gotchas

- `.yarn/releases/yarn-4.18.0.cjs` is 3696KB. 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/storybookjs/storybook.md

A draft gets the commands right and stops at the things only a maintainer knows. What a good TypeScript 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/storybookjs/storybook.svg)](https://agentreadme.com/storybookjs/storybook)

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