Report · marked 26 Aug 2026
JetBrains/kotlin
An agent will struggle here, mostly for fixable reasons.
Kotlin · 53,353 stars · 41,052 files · branch master
41
/100
C
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
2/18Whether an agent can install the project and get it running without a human. Losing marks on deterministic install and discoverable commands.Verification loop
4/22Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy. Losing marks on tests exist and test command is discoverable.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
5/10How quickly anything new can orient itself. Losing marks on written documentation and license.
Higher is better. Accent marks what is costing you most.
Fix these first
01
Test command is discoverable
Add a `test` script or a `test` target that runs the whole suite with no arguments. The convention is the interface — an agent tries `npm test` and `make test` before it tries reading your CI config.
02
Deterministic install
Commit the lockfile your package manager generates. Without it, an agent's install and your install are different builds, and 'works on my machine' becomes unfalsifiable.
03
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.
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.
Also found: CLAUDE.md
✗Instruction quality
6/12
Real instructions, with gaps.
Worth fixing: it never states a build, test, or run command; has no code blocks.
234 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 2/18 F
Whether an agent can install the project and get it running without a human.
✗Deterministic install
0/6
No lockfile. An agent installing dependencies may not get what CI got.
Commit the lockfile your package manager generates. Without it, an agent's install and your install are different builds, and 'works on my machine' becomes unfalsifiable.
✗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
2/4
Env vars are mentioned in the README but there's no example file to copy.
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
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 4/22 F
Whether an agent can check its own work. This is the category that most decides whether agent output is trustworthy.
✗Tests exist
4/8
949 test files against 21822 source files.
Coverage is thin enough that an agent can break real behavior and still see green.
e.g. .idea/runConfigurations/Compiler_Native_Image__Smoke_Test.xml, analysis/analysis-api-fir/testFixtures/org/jetbrains/kotlin/analysis/api/fir/test/TestGenerator.kt, analysis/analysis-api-fir/testFixtures/org/jetbrains/kotlin/analysis/api/fir/test/cases/imports/AbstractKaDefaultImportsProviderTest.kt
✗Test command is discoverable
0/7
There's no obvious way to run the tests. Even if tests exist, an agent won't reliably find the entry point.
Add a `test` script or a `test` target that runs the whole suite with no arguments. The convention is the interface — an agent tries `npm test` and `make test` before it tries reading your CI config.
✗Continuous integration
0/4
No CI config. Nothing outside a developer's laptop enforces correctness.
A CI workflow doubles as machine-readable documentation: it's the one file that states, unambiguously, the exact commands that must succeed.
✗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 Kotlin 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 72 patterns.
✗File sizes fit in context
0/6
41 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.
build-common/testFixtures/org/jetbrains/kotlin/metadata/DebugProtoBuf.java — 1853KB
analysis/analysis-api-fir-diagnostics/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnostic.kt — 406KB
analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnosticsImpl.kt — 306KB
✗Repository weight
0/5
About 4856MB 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 45,777 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 The Kotlin Programming Language. ## Setup ``` # TODO: the install command. No lockfile was found, so this could not be inferred. ``` ## Commands ``` # TODO: nothing declares a build or test command, so an agent has to guess. # This is the single most valuable section of this file. Fill it in. ``` ## Layout - `analysis/` 11135 source files - `compiler/` 10586 source files - `build-common/` 82 source files - `benchmarks/` 19 source files ## Conventions - Tests live alongside the code they cover, following `.idea/runConfigurations/Compiler_Native_Image__Smoke_Test.xml`. - TODO: add the two or three conventions a newcomer always gets wrong here. ## Gotchas - `build-common/testFixtures/org/jetbrains/kotlin/metadata/DebugProtoBuf.java` is 1853KB. It will not fit comfortably in context, so read it in parts. - No lockfile is committed, so an install here may not match what CI produced. --- 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/JetBrains/kotlin.md
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[](https://agentreadme.com/JetBrains/kotlin)Other Kotlin repositories, marked
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.
This repository is large enough that GitHub truncated the file listing, so the file-level checks ran on a sample.