Report · marked 26 Aug 2026
denoland/deno
An agent can work here, but it will waste turns finding its footing.
Rust · 108,308 stars · 14,822 files · branch main
69
/100
B
Instructions
24/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on agent instruction file.Setup
10/20Whether an agent can install the project and get it running without a human. Losing marks on discoverable commands and environment config.Verification loop
19/22Whether 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.Context economy
5/20Whether 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
Discoverable commands
Declare the handful of commands that matter in package.json scripts, a Makefile, or a justfile. Naming them turns guesswork into a lookup.
02
No committed build output
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.
03
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.
The full marking
Every deduction below names the file or setting it came from.
Instructions 24/27 A
Whether the repo tells an agent how to behave before it starts guessing.
✗Agent instruction file
9/12
CLAUDE.md 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 CLAUDE.md alongside it costs nothing.
Also found: Copilot instructions
✓Instruction quality
12/12
Specific enough that an agent can act on it.
11,861 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 10/20 C+
Whether an agent can install the project and get it running without a human.
✓Deterministic install
6/6
cargo.lock pins the dependency tree.
Found cargo.lock
✗Discoverable commands
0/6
No declared commands. An agent has to infer how to build and run this from the file tree.
Declare the handful of commands that matter in package.json scripts, a Makefile, or a justfile. Naming them turns guesswork into a lookup.
✗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 rust-toolchain.toml
✓Reproducible environment
2/2
.devcontainer/devcontainer.json gives a known-good environment.
Verification loop 19/22 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
12616 test files against 6244 source files.
e.g. .github/workflows/ecosystem_compat_test.ts, .github/workflows/node_compat_test.ts, cli/js/40_test.js
✓Test command is discoverable
7/7
An agent can find and run `cargo test`.
✓Continuous integration
4/4
11 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
n/a
Not applicable — the Rust compiler type checks every build.
Context economy 5/20 F
Whether the repo fits in a context window, or fights it.
✗No committed build output
0/6
Generated output is committed: node_modules/, coverage/.
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 33 patterns.
✗File sizes fit in context
0/6
46 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.
cli/tsc/00_typescript.js — 8930KB
cli/tsc/dts/lib.dom.d.ts — 2295KB
cli/tsc/dts/lib.webworker.d.ts — 769KB
✗Repository weight
2/5
About 247MB 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 A modern runtime for JavaScript and TypeScript. ## Setup ``` cargo build ``` ## Commands ``` cargo test # run the test suite ``` ## Layout - `tests/` 4486 source files - `ext/` 647 source files - `libs/` 544 source files - `cli/` 436 source files - `runtime/` 63 source files - `tools/` 56 source files ## Conventions - Tests live alongside the code they cover, following `.github/workflows/ecosystem_compat_test.ts`. - CI defines what passing means. See `.github/workflows/cargo_publish.generated.yml`, and keep it green. - TODO: add the two or three conventions a newcomer always gets wrong here. ## Gotchas - `cli/tsc/00_typescript.js` is 8930KB. 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/denoland/deno.md
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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.