Report · marked 25 Aug 2026

sveltejs/svelte

Solid foundations, held back in a few specific places.

JavaScript · 87,987 stars · 9,148 files · branch main

84 /100 A-

Instructions 20/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on instruction quality and readme as an entry point.Setup 12/14Whether an agent can install the project and get it running without a human. Losing marks on pinned runtime version.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 static type checking.Context economy 17/20Whether 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

Instruction quality

Worth fixing: it never states a build, test, or run command; has no code blocks.

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.

Pinned runtime version

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

The full marking

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

Instructions 20/27 B+

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.

✗Instruction quality 6/12

Real instructions, with gaps.

Worth fixing: it never states a build, test, or run command; has no code blocks.

589 characters, a workable length

uses headings, so an agent can skim it

✗README as an entry point 2/3

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 12/14 A

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

✓Deterministic install 6/6

pnpm-lock.yaml pins the dependency tree.

Found pnpm-lock.yaml

✓Discoverable commands 6/6

Commands are declared where an agent will look for them.

package.json scripts (build, check, lint, format, test, changeset:version…)

–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 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

8483 test files against 8034 source files.

e.g. benchmarking/benchmarks/reactivity/tests/clean_effects.bench.js, benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js, benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js

✓Test command is discoverable 7/7

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

✓Continuous integration 4/4

4 GitHub Actions workflows define what "passing" means.

✓Lint and format rules 3/3

eslint.config.js encodes the house style.

✗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 17/20 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 15 patterns.

✗File sizes fit in context 4/6

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.

packages/svelte/types/index.d.ts — 124KB

✗Repository weight 4/5

About 121.9MB 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 sveltejs/svelte

# AGENTS.md

web development for the rest of us

## Setup

```
pnpm install
```

## Commands

```
pnpm build               # produce a build
pnpm test                # run the test suite, must pass before any commit
pnpm lint                # lint
pnpm format              # format
pnpm check               # lint and type check
pnpm changeset:version
pnpm changeset:publish
pnpm bench
```

## Layout

- `packages/`     7994 source files
- `benchmarking/` 25 source files
- `playgrounds/`  11 source files

## Conventions

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

## Gotchas

- `packages/svelte/types/index.d.ts` is 124KB. 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/sveltejs/svelte.md

Show the mark

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[![agent ready](https://agentreadme.com/badge/sveltejs/svelte.svg)](https://agentreadme.com/sveltejs/svelte)

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All JavaScript 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