# Gemini Cli Rs

> Gemini CLI in Rust — Google AI Studio API with MCP server support for Claude Code

- **Type:** MCP server
- **Install:** `agentstack add mcp-heki1224-gemini-cli-rs`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [heki1224](https://agentstack.voostack.com/s/heki1224)
- **Installs:** 0
- **Category:** [Integrations](https://agentstack.voostack.com/c/integrations)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [heki1224](https://github.com/heki1224)
- **Source:** https://github.com/heki1224/gemini-cli-rs

## Install

```sh
agentstack add mcp-heki1224-gemini-cli-rs
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# gemini-cli-rs

English | [日本語](README.ja.md)

Gemini CLI written in Rust, optimized for use as an [MCP](https://modelcontextprotocol.io/) tool in Claude Code.

## Features

- **MCP Server mode** — Runs as a native MCP server (`--mcp-server`); integrates directly with Claude Code
- **SSE Streaming** — Streams responses from the Gemini API in real time
- **Google Search Grounding** — Always-on; sources are printed to stderr in CLI mode and included in the response in MCP mode
- **GEMINI.md Context** — Loads project-specific context from `GEMINI.md` (walks up to the nearest `.git` root)
- **Single-shot mode** — Designed for non-interactive, scriptable use

## Prerequisites

- A Gemini API key (`GEMINI_API_KEY`) — get one at [Google AI Studio](https://aistudio.google.com/apikey)

## Installation

### Download pre-built binary

Pre-built binaries are available for macOS and Linux on the [Releases page](https://github.com/heki1224/gemini-cli-rs/releases/latest).

```bash
# Apple Silicon macOS
curl -L https://github.com/heki1224/gemini-cli-rs/releases/latest/download/gemini-cli-rs-aarch64-apple-darwin.tar.xz | tar -xJ
mv gemini ~/.local/bin/gemini

# Intel macOS
curl -L https://github.com/heki1224/gemini-cli-rs/releases/latest/download/gemini-cli-rs-x86_64-apple-darwin.tar.xz | tar -xJ
mv gemini ~/.local/bin/gemini

# Linux x86_64
curl -L https://github.com/heki1224/gemini-cli-rs/releases/latest/download/gemini-cli-rs-x86_64-unknown-linux-gnu.tar.xz | tar -xJ
mv gemini ~/.local/bin/gemini
```

### Build from source

```bash
git clone https://github.com/heki1224/gemini-cli-rs
cd gemini-cli-rs
cargo build --release
cp target/release/gemini ~/.local/bin/gemini
```

## Usage

### CLI mode

```bash
# Set your API key
export GEMINI_API_KEY="your-api-key"

# Send a prompt
gemini -p "What is the capital of France?"

# Use a different model
gemini -m gemini-2.5-pro -p "Explain Rust's borrow checker"
```

Grounding sources are printed to **stderr** after the response.

### MCP server mode

In MCP mode the binary is launched automatically by Claude Code — you do not normally run it directly. See [MCP Setup](#mcp-setup-claude-code) for registration steps.

```bash
# Manual launch (for debugging)
GEMINI_API_KEY="your-api-key" gemini --mcp-server
```

Grounding sources are included **in the response text** (not stderr).

### MCP HTTP server mode (streamable-http) — experimental

For non-stdio integrations (browser-based clients, separate processes, container setups), the binary can also serve JSON-RPC 2.0 over HTTP using the [streamable-http](https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#streamable-http) transport.

```bash
GEMINI_API_KEY="your-api-key" gemini --mcp-http-port 3002
# Listening on http://127.0.0.1:3002/mcp
```

| Property | Value |
|----------|-------|
| Listen address | `127.0.0.1:` (loopback only — not reachable from LAN/Docker host) |
| Endpoint | `POST /mcp` |
| Transport | Stateless request/response. Server-initiated notifications are not supported. |
| CORS | All origins allowed (development convenience) |
| Body limit | 10 MB |

> **Security warning:** Because CORS allows any origin, a malicious page open in your browser can send requests to `127.0.0.1:/mcp` and trigger Gemini API calls billed to your key. Use this mode only on trusted machines for local development. The official Claude Code MCP integration uses stdio (`--mcp-server`); HTTP mode is provided for ad-hoc tooling.

## Options

| Flag | Description | Default |
|------|-------------|---------|
| `-p, --prompt` | Prompt to send (required in CLI mode) | — |
| `-m, --model` | Model to use | `gemini-3.5-flash` |
| `--mcp-server` | Run as MCP server (JSON-RPC 2.0 over stdio) | — |
| `--mcp-http-port ` | Run as MCP server over HTTP (streamable-http) on `127.0.0.1:` | — |

The API key is read from the `GEMINI_API_KEY` environment variable only (no `--api-key` flag).

### Environment variables

| Variable | Description | Default |
|----------|-------------|---------|
| `GEMINI_API_KEY` | Gemini API key (required) | — |
| `GEMINI_DEFAULT_MODEL` | Override the default model at runtime | `gemini-3.5-flash` |
| `GEMINI_HIGH_PERF_MODEL` | Override the high-performance model at runtime | `gemini-3.1-pro-preview` |

## MCP Setup (Claude Code)

This tool is designed to be used as an MCP server inside Claude Code, providing Gemini with Google Search Grounding as a secondary AI assistant.

### 1. Build the binary

```bash
cargo build --release
```

### 2. Register as an MCP server

```bash
claude mcp add gemini /path/to/target/release/gemini --scope user -- --mcp-server
```

Use `--scope user` to make it available across all projects, or `--scope project` to limit it to the current project.

### 3. Set your API key

Add `GEMINI_API_KEY` to your shell profile (`~/.zshrc`, `~/.bashrc`, etc.):

```bash
export GEMINI_API_KEY="your-api-key"
```

### 4. Restart Claude Code and verify

```bash
claude mcp list
```

Once registered, the `ask_gemini_mcp` tool is available. Claude Code routes prompts to Gemini with real-time Google Search grounding.

### MCP tool parameters

| Parameter | Type | Description |
|-----------|------|-------------|
| `prompt` | string (required) | The prompt to send to Gemini. Aliases `request`, `query`, `message`, `text`, `input` are also accepted as fallbacks |
| `model` | string | Override the model for this request (ignored when `thinking=true`) |
| `thinking` | boolean | Use the high-performance model (`gemini-3.1-pro-preview`) for complex reasoning or deep analysis. Default: `false` |

> **Note:** The binary writes protocol messages to stdout and all logs to stderr. Do not redirect stderr if you want to see debug output.

## GEMINI.md

Place a `GEMINI.md` file in your current working directory (or any parent directory) to inject system-level context into every request. The search walks up to the nearest `.git` directory; if no `.git` is found, it continues to the filesystem root. Useful for project-specific instructions.

> **Note:** Files larger than 1 MB are silently ignored.

```
your-project/
├── .git/
├── GEMINI.md   ← loaded automatically
└── src/
```

## License

MIT — see [LICENSE](LICENSE)

## Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [heki1224](https://github.com/heki1224)
- **Source:** [heki1224/gemini-cli-rs](https://github.com/heki1224/gemini-cli-rs)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** yes
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/mcp-heki1224-gemini-cli-rs
- Seller: https://agentstack.voostack.com/s/heki1224
- Browse the marketplace: https://agentstack.voostack.com/browse

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