CostGate

Gate your MCP. Cut your bill.

CostGate reduces AI token consumption by optimizing MCP tool definitions and responses.
Cursor-first, compatible with Claude Desktop and other MCP clients.

Languages: English (this file) · 日本語

Repository layout (monorepo)

costgate/
├── packages/
│   ├── schema/     @costgate/schema   — shared log schema
│   ├── probe/      @costgate/probe    — measurement MCP (npm)
│   ├── cli/        @costgate/cli      — npm entry (launcher, Dashboard, hooks)
│   └── gate/       costgate-gate      — gateway MCP (Go binary)
├── docs/
├── examples/
└── scripts/

See docs/structure.md for why Probe and Gate share one repo.

Related MCP server: Refract

Packages

Quick start (production — recommended)

Install with Node only (no Go build). init downloads the Gate binary from GitHub Releases.

npx @costgate/cli@latest init
# Restart Cursor (reconnect MCP)

What init does:

• ~/.costgate/bin/costgate-gate — Go binary

• ~/.cursor/mcp.json — npx @costgate/cli gate (Dashboard auto-start)

• ~/.cursor/hooks.json — Shield, prompt-intent, etc.

• ~/.costgate/backends.json — template (if missing)

Update: npx @costgate/cli update

Details: packages/cli/README.md · docs/releases.md

Global install (optional)

npm install -g @costgate/cli
costgate init

Quick start (developers — clone repo)

git clone https://github.com/YukiMiyatake/costgate.git
cd costgate
npm install
npm run build:gate          # or ./scripts/install-gate.sh
cp examples/backends.github.json ~/.costgate/backends.json
npm run cursor:production   # update mcp.json with local paths
npm run cursor:registry     # install hooks

Docker only: docs/docker.md

Quick start (Probe — measurement only)

Option A — npx (published)

npx @costgate/probe@latest

Add to Cursor ~/.cursor/mcp.json:

{
  "mcpServers": {
    "costgate-probe": {
      "command": "npx",
      "args": ["-y", "@costgate/probe"],
      "env": {
        "COSTGATE_CONFIG": "~/.costgate/backends.json",
        "COSTGATE_PROBE_LOG_DIR": "~/.costgate/logs"
      }
    }
  }
}

Option B — from source

npm install
npm run build:probe

See examples/cursor/ for measurement configuration.

Gate (advanced — binary only)

Minimal setup without Dashboard or hooks:

./scripts/install-gate.sh          # → ~/.local/bin/costgate-gate
costgate-gate --version

Example ~/.cursor/mcp.json: examples/cursor/mcp-gate-github.json

Build from repo: npm run build:gate (Go 1.25+)

Releases: GitHub Releases · docs/RELEASE.md

Filter mode (default): Tier A/B/C + discover_tools / invoke_tool. See packages/gate/README.md.

Compare reduction: npm run compare (definitions) · npm run compress-report (definitions + tool results).

Session breakdown: npm run session-report (fixed + variable + overall % scenarios).

Measured benchmarks: docs/benchmarks.md

Production Cursor setup (clone): npm run cursor:production — see examples/cursor/README.md.

Cloud metrics (opt-in): npm run cloud:upload — see costgate-cloud.

Plans (roadmap)

OSS vs Cloud feature split: docs/ecosystem/plans.md · 日本語

See docs/roadmap.md for OSS phase details.

Documentation

• Documentation languages

• Development roadmap · 日本語

• MCP Dashboard (users) · 日本語

• MCP token reduction survey · 日本語

• MCP Dashboard (developers) · 日本語

• Benchmarks & verification · 日本語

• Repository structure · 日本語

• OSS vs Cloud plans · 日本語

• Docker / Dev Container · 日本語

• Gate releases · 日本語

• Architecture · 日本語

• Log schema · 日本語

• Contributing · 日本語

License

MIT — see LICENSE