What is mfs CLAUDE.md?

A project instruction document describing how the MFS monorepo works. A monorepo is one repository containing multiple related parts, such as a command-line client, server, and software libraries.

Use it when working on MFS, especially changes involving the Rust command-line client, Python server, connectors, storage, or generated software libraries.

It gives developers the cross-project rules and architecture details needed to change the right component without duplicating business logic.

How zilliztech/mfs configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to zilliztech/mfs. 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/zilliztech/mfs/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/zilliztech/mfs

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/zilliztech/mfs/claude-md/github.svg)](https://agentmods.dev/instructions/zilliztech/mfs/claude-md)

Your own site

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

Per session 1,780 This file is loaded in full into every session.

When invoked 1,780 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	$0.01780	$0.01780
Opus 5.5	$0.00712	$0.00712
Sonnet 5.5	$0.00356	$0.00356
Haiku 4.5	$0.00178	$0.00178

Measured 1mo ago against content hash 36752ae1b448, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mfs 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 1mo 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 · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

What this is

MFS exposes many sources (code, docs, messages, databases, object stores) as one file-like, searchable namespace. It is a monorepo of two cooperating processes:

cli/ — a thin Rust CLI (mfs). It is only an HTTP client of the server; it holds no business logic. Don't add behavior here that belongs on the server.
server/python/ — the Python server (mfs-server, FastAPI). It owns connectors, the ingest pipeline, the vector index, and storage, exposed over an HTTP /v1 control plane. This is where almost all work happens.

The SDKs (sdks/python, sdks/typescript) are generated from protocol/openapi.yaml. server-rs/ is an optional PyO3 acceleration wheel with a transparent pure-Python fallback (mfs_server.common.accel) — never required.

CONTRIBUTING.md and docs/architecture.md are the long-form references; the points below are the ones that need several files to piece together.

Commands

All Python commands run from server/python/. dev is an extra, not a dependency-group — uv run pytest fails (no pytest); always use --extra dev:

uv sync                                   # default deps (local ONNX, Milvus Lite, SQLite)
uv run --extra dev pytest                 # all unit/smoke tests
uv run --extra dev pytest tests/test_engine_chunkable_e2e.py::test_chunkable_path_drains_through_pipeline   # one test
uv run --extra dev ruff format --check src/ tests/    # what CI enforces
uv run --extra dev ruff check src/ tests/             # lint (loose; not gated in CI)
uv run mfs-server run                     # run server from checkout, binds 127.0.0.1:13619

A few tests import optional connector SDKs (e.g. lark_oapi) and fail to collect without them; --ignore those files or uv sync --extra all-connectors.
CI (.github/workflows/lint.yml) enforces formatting only — ruff format --check and cargo fmt --all -- --check. Tests are not gated, so run them yourself.

Read the full file on GitHub · 130 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.

1mo ago First seen · 130 lines · 1,780 tokens per session scan A 36752ae1b448

Subscribe to this mod's changes

mfs CLAUDE.md is an instructions file published in the GitHub repository zilliztech/mfs (157 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 1,780 tokens to every session, about $0.0071 per session on Opus 5.5. 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.

Claude Code agent agent-memory codex embeddings file-search

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 · 9,715 tokens

mfs: Instructions file for Claude Code

Borrowing it

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

CLAUDE.md

What this is

Commands

What this file has done since we first saw it

Other instructions, from other repositories

vscode buildNext.instructions.md

next.js AGENTS.md

vscode oss-third-party-notices.instructions.md

langchain AGENTS.md

vscode copilot-instructions.md

vscode model-prompts.instructions.md