What is yorkie CLAUDE.md?

Agent instructions for Yorkie, a Go server that synchronizes shared documents using CRDTs and MongoDB or in-memory storage. A CRDT is a data structure designed so changes from different users or servers can be merged consistently.

Use them when changing Yorkie's document synchronization, server behavior, protobuf files, tests, benchmarks, or integration environment.

They explain the architecture, commands, integration-test setup, and commit format needed to work safely on the server. This helps distinguish unit tests from tests that require MongoDB and prevents unclear commits.

How yorkie-team/yorkie configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to yorkie-team/yorkie. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/yorkie-team/yorkie/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/yorkie-team/yorkie

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/yorkie-team/yorkie/claude-md/github.svg)](https://agentmods.dev/instructions/yorkie-team/yorkie/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/yorkie-team/yorkie/claude-md"><img src="https://agentmods.dev/badge/instructions/yorkie-team/yorkie/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/yorkie-team/yorkie/claude-md"><img src="https://agentmods.dev/badge/instructions/yorkie-team/yorkie/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,039 This file is loaded in full into every session.

When invoked 1,039 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01039	$0.01039
Opus 5	$0.00519	$0.00519
Sonnet 5	$0.00208	$0.00208
Haiku 4.5	$0.00104	$0.00104

Measured 10d ago against content hash 887a030a5279, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

yorkie CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Yorkie — CRDT-based Collaboration Server

Go server providing document synchronization via CRDTs with MongoDB or in-memory storage.

Architecture docs live under docs/design/; tasks under @docs/tasks/README.md.

Commands

make tools         # Install dev tools (run periodically)
make build         # Build binary to bin/yorkie
make fmt           # gofmt
make lint          # golangci-lint
make proto         # Regenerate protobuf via buf
make test          # Integration tests (-tags integration, MongoDB required)
make test-complex  # Long-running complex tests (-tags complex)
make bench         # Benchmarks (-tags bench)
make coverage      # Integration test coverage (MongoDB required)
go test ./...      # Unit-only tests (no build tag, no DB)

# Integration test environment
docker compose -f build/docker/docker-compose.yml up --build -d

Commit Messages

Per CONTRIBUTING.md: subject ≤70 chars (what changed), blank line, body wrapped at 80 chars (why). Enable the local commit-msg validator once with bash scripts/setup.sh.

Skip leadership write when active leader exists

Follower nodes unconditionally attempted FindOneAndUpdate with
is_leader=true every renewal cycle (default 5s). With N nodes this
produced N-1 duplicate key errors per cycle on the
is_leader_true_unique partial index.

In shell, use multiple -m flags or $'...' for real newlines — not \n inside "...".

Key Architecture

Three-layer data model: JSON-like (user-facing) → CRDT (conflict resolution) → Common (shared primitives).
Entry point: cmd/yorkie/.
Generated code: api/yorkie/v1/ (protobuf via make proto).
Design docs: docs/design/ — always consult before changing architecture; keep updated when behavior changes.

Pitfalls

Build tags integration, bench, complex gate test files. The Makefile targets pass them via go test -tags …; for VSCode/gopls to index those files, set gopls.build.buildFlags per CONTRIBUTING.md.
Apache 2.0 license header required on every Go file.
Follow Uber Go Style Guide; every package needs a package comment (// Package xxx provides…).
protobuf is generated — regenerate via make proto, don't hand-edit api/yorkie/v1/*.pb.go.
No direct push to main; all changes via PR. CodeRabbit auto-reviews every PR.

Read the full file on GitHub · 98 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

10d ago First seen · 98 lines · 1,039 tokens per session scan A 887a030a5279

Subscribe to this mod's changes

yorkie CLAUDE.md is an instructions file published in the GitHub repository yorkie-team/yorkie (927 stars, last pushed yesterday), licensed Apache-2.0. It adds 1,039 tokens to every session, about $0.0052 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

collaborative-applications crdt grpc hacktoberfest realtime-collaboration yorkie

next.js AGENTS.md

AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

openai/codex · 5,153 tokens

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

yorkie: Instructions file for Claude Code