Report · marked 26 Aug 2026
vercel/next.js
Solid foundations, held back in a few specific places.
JavaScript · 141,932 stars · 31,503 files · branch canary
78
/100
A-
Instructions
23/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on instruction quality and readme as an entry point.Setup
16/20Whether an agent can install the project and get it running without a human. Losing marks on environment config.Verification loop
22/22Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy. Full marks.Context economy
6/20Whether the repo fits in a context window, or fights it. Losing marks on no committed build output and 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
01
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.
02
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.
03
README as an entry point
Give the README an Install and a Usage heading with real commands under each. Agents pattern-match on those headings.
The full marking
Every deduction below names the file or setting it came from.
Instructions 23/27 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
✗Instruction quality
10/12
Specific enough that an agent can act on it.
Worth fixing: it's 31k characters, which burns context on every single turn.
names the actual commands to run
uses headings, so an agent can skim it
includes copyable code blocks
✗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 16/20 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 (new-error, new-test, pr-adopt, clean, build, build-all…)
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 .node-version
✓Reproducible environment
2/2
.devcontainer/devcontainer.json gives a known-good environment.
Verification loop 22/22 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
20882 test files against 24349 source files.
e.g. .config/ast-grep/rule-tests/no-context-format-test.yml, .config/ast-grep/rule-tests/no-context-test.yml, .config/ast-grep/rule-tests/no-err-anyhow-test.yml
✓Test command is discoverable
7/7
An agent can find and run `npm run test`.
✓Continuous integration
4/4
38 GitHub Actions workflows define what "passing" means.
✓Lint and format rules
3/3
eslint.config.mjs encodes the house style.
–Static type checking
n/a
Not applicable — the Rust compiler type checks every build.
Context economy 6/20 D
Whether the repo fits in a context window, or fights it.
✗No committed build output
3/6
Generated output is committed: node_modules/.
Add these to .gitignore and `git rm -r --cached` them. Generated files pollute search results, so an agent grepping for a function finds the compiled copy and edits the wrong file.
✓.gitignore hygiene
3/3
.gitignore covers 58 patterns.
✗File sizes fit in context
0/6
132 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.
packages/next/src/compiled/webpack/bundle5.js — 2522KB
turbopack/crates/turbopack-ecmascript/tests/benches/packages-bundle.js — 2108KB
packages/next/src/compiled/babel-packages/packages-bundle.js — 1504KB
✗Repository weight
0/5
About 2542MB 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 The React Framework ## Setup ``` pnpm install ``` ## Commands ``` pnpm dev # run locally pnpm build # produce a build pnpm test # run the test suite, must pass before any commit pnpm lint # lint pnpm new-error pnpm new-test pnpm pr-adopt pnpm clean ``` ## Layout - `test/` 13934 source files - `turbopack/` 3528 source files - `packages/` 3049 source files - `examples/` 2187 source files - `crates/` 1063 source files - `bench/` 276 source files ## Conventions - Tests live alongside the code they cover, following `.config/ast-grep/rule-tests/no-context-format-test.yml`. - TypeScript is not in strict mode. Turning it on catches a whole class of mistakes before they run. - CI defines what passing means. See `.github/workflows/automated_code_review.yml`, and keep it green. - TODO: add the two or three conventions a newcomer always gets wrong here. ## Gotchas - `packages/next/src/compiled/webpack/bundle5.js` is 2522KB. 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/vercel/next.js.md
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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.