Report · marked 25 Aug 2026
PostHog/posthog
Solid foundations, held back in a few specific places.
Python · 39,151 stars · 45,890 files · branch master
84
/100
A-
Instructions
25/27Whether the repo tells an agent how to behave before it starts guessing. Losing marks on instruction quality.Setup
20/20Whether an agent can install the project and get it running without a human. Full marks.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
9/20Whether the repo fits in a context window, or fights it. Losing marks on file sizes fit in context and repository weight.Navigability
7/10How quickly anything new can orient itself. Losing marks on license.
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
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.
03
License
Without a license nobody can safely reuse this, and some tools will refuse to work with it at all.
The full marking
Every deduction below names the file or setting it came from.
Instructions 25/27 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, .cursorrules
✗Instruction quality
10/12
Specific enough that an agent can act on it.
Worth fixing: it's 41k 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
3/3
README has a clear getting-started section.
Setup 20/20 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 (prepare, schema:build, openapi:build, schema:build:python, taxonomy:build, taxonomy:build:json…)
✓Environment config
4/4
.env.example documents what the app needs to run.
✓Pinned runtime version
2/2
The language runtime version is pinned.
Found .nvmrc
✓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
10842 test files against 35264 source files.
e.g. .depot/actions/paths-filter/__tests__/csv-escape.test.ts, .depot/actions/paths-filter/__tests__/filter.test.ts, .depot/actions/paths-filter/__tests__/git.test.ts
✓Test command is discoverable
7/7
An agent can find and run `npm run test:unit`.
✓Continuous integration
4/4
128 GitHub Actions workflows define what "passing" means.
✓Lint and format rules
3/3
pyproject.toml 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 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 156 patterns.
✗File sizes fit in context
0/6
249 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.
services/mcp/src/api/generated.ts — 3766KB
rust/cymbal/tests/static/chunk-PGUQKT6S.js — 2280KB
rust/cymbal/tests/static/sourcemaps/1234.js — 2280KB
✗Repository weight
0/5
About 6656MB 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 :hedgehog: PostHog is the leading platform for building self-driving products. Our developer tools – AI observability, analytics, session replay, flags, experiments, error tracking, logs, and more – capture all the context agents need to diagnose problems, uncover opportunities, and ship fixes. Steer it all from Slack, web, desktop, or the MCP. ## Setup ``` pnpm install ``` ## Commands ``` pnpm start # run the app pnpm lint # lint pnpm format # format pnpm prepare pnpm schema:build pnpm openapi:build pnpm schema:build:python pnpm taxonomy:build ``` ## Layout - `products/` 20341 source files - `frontend/` 5376 source files - `posthog/` 3291 source files - `nodejs/` 1570 source files - `rust/` 1393 source files - `ee/` 820 source files ## Conventions - Tests live alongside the code they cover, following `.depot/actions/paths-filter/__tests__/csv-escape.test.ts`. - 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/_rust-build-images.yml`, and keep it green. - TODO: add the two or three conventions a newcomer always gets wrong here. ## Gotchas - `services/mcp/src/api/generated.ts` is 3766KB. It will not fit comfortably in context, so read it in parts. - Copy `.env.example` before running anything that needs configuration. --- 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/PostHog/posthog.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.