Report · marked 26 Aug 2026

mermaid-js/mermaid

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

TypeScript · 89,939 stars · 3,093 files · branch develop

69 /100 B

Instructions 2/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on agent instruction file and instruction quality.Setup 16/20Whether an agent can install the project and get it running without a human. Losing marks on environment config.Verification loop 25/25Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy. Full marks.Context economy 17/20Whether the repo fits in a context window, or fights it. Losing marks on 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

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.

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.

The full marking

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

Instructions 2/27 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 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 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 (clean, copy:dompurify, copy:mermaid, copy:editor, serve:dist, build…)

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

dockerfile gives a known-good environment.

Verification loop 25/25 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

342 test files against 1048 source files.

e.g. e2e/diagrams/journey/simple-test.mmd, e2e/diagrams/sequence/should-render-all-message-types-and-arrow-types-in-a-single-comprehensive-test.mmd, e2e/helpers/argos-metadata.spec.ts

✓Test command is discoverable 7/7

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

✓Continuous integration 4/4

23 GitHub Actions workflows define what "passing" means.

✓Lint and format rules 3/3

eslint.config.js encodes the house style.

✓Static type checking 3/3

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

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 64 patterns.

✓File sizes fit in context 6/6

No source file is large enough to crowd out a context window.

✗Repository weight 2/5

About 277MB 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 mermaid-js/mermaid

# AGENTS.md

Generation of diagrams like flowcharts or sequence diagrams from text in a similar manner as markdown

## 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 clean
pnpm copy:dompurify
pnpm copy:mermaid
pnpm copy:editor
```

## Layout

- `packages/` 931 source files
- `e2e/`      75 source files
- `scripts/`  15 source files
- `tests/`    2 source files
- `demos/`    1 source file

## Conventions

- Tests live alongside the code they cover, following `e2e/diagrams/journey/simple-test.mmd`.
- 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/autofix.yml`, and keep it green.
- TODO: add the two or three conventions a newcomer always gets wrong here.

---

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/mermaid-js/mermaid.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/mermaid-js/mermaid.svg)](https://agentreadme.com/mermaid-js/mermaid)

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Think this mark is wrong?

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