Report · marked 25 Aug 2026

microsoft/TypeScript

Solid foundations, held back in a few specific places.

Go · 110,686 stars · 51,205 files · branch main

82 /100 A-

Instructions 23/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on agent instruction file.Setup 16/16Whether an agent can install the project and get it running without a human. Full marks.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 9/20Whether the repo fits in a context window, or fights it. Losing marks on file sizes fit in context and repository weight.Navigability 8/10How quickly anything new can orient itself. Losing marks on written documentation.

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.

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.

Agent instruction file

Rename or symlink to AGENTS.md so tools other than one vendor's can read it. Keeping Copilot instructions alongside it costs nothing.

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 8/12

Copilot instructions is present, but not the vendor-neutral AGENTS.md.

Rename or symlink to AGENTS.md so tools other than one vendor's can read it. Keeping Copilot instructions alongside it costs nothing.

✓Instruction quality 12/12

Specific enough that an agent can act on it.

5,291 characters, a workable length

names the actual commands to run

uses headings, so an agent can skim it

includes copyable code blocks

✓README as an entry point 3/3

README has a clear getting-started section.

Setup 16/16 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 (build, build:watch, build:watch:debug, test, lint, format…)

–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 >=20.19

✓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

4556 test files against 17538 source files.

e.g. packages/typescript/test/api.bench.ts, packages/typescript/test/async/api.bench.ts, packages/typescript/test/async/api.test.ts

✓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 3/3

.golangci.yml encodes the house style.

–Static type checking n/a

Not applicable — the Go compiler type checks every build.

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 112 patterns.

✗File sizes fit in context 0/6

43 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.

tsc/internal/fourslash/tests/codeFixClassImplementInterfaceNoTruncation_test.go — 3935KB

tsc/internal/bundled/libs/lib.dom.d.ts — 2294KB

tsc/internal/fourslash/tests/codeFixClassImplementInterfaceNoTruncationProperties_test.go — 1467KB

✗Repository weight 0/5

About 2930MB 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.

File tree exceeded GitHub's limit, so 51,433 entries were sampled

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 microsoft/TypeScript

# AGENTS.md

TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

## Setup

```
npm ci
```

## Commands

```
npm run build               # produce a build
npm run test                # run the test suite, must pass before any commit
npm run lint                # lint
npm run format              # format
npm run build:watch
npm run build:watch:debug
npm run check:format
npm run generate
```

## Layout

- `tsc/`      17362 source files
- `packages/` 144 source files
- `tools/`    31 source files

## Conventions

- Tests live alongside the code they cover, following `packages/typescript/test/api.bench.ts`.
- CI defines what passing means. See `.github/workflows/accept-baselines-fix-lints.yaml`, and keep it green.
- TODO: add the two or three conventions a newcomer always gets wrong here.

## Gotchas

- `tsc/internal/fourslash/tests/codeFixClassImplementInterfaceNoTruncation_test.go` is 3935KB. 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/microsoft/TypeScript.md

Show the mark

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[![agent ready](https://agentreadme.com/badge/microsoft/TypeScript.svg)](https://agentreadme.com/microsoft/TypeScript)

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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.

Open an issue, already filled in

This repository is large enough that GitHub truncated the file listing, so the file-level checks ran on a sample.