Server Claude Chat

An MCP (Model Context Protocol) server for the Anthropic Claude Messages API. Built in Rust, it exposes chat, vision, live web search, and model listing as MCP tools — so any MCP client (Claude Desktop, Claude Code, etc.) can consult Claude as a tool.

Communicates via stdio using JSON-RPC 2.0, like all the other MCP servers in this collection. Structurally it mirrors mcp-server-grok-chat / mcp-server-gpt-chat, adapted to Anthropic's API shape.

Subscription vs. API credits

This server uses the Anthropic API with an API key (API credits). That is the only supported, terms-compliant way to drive Claude from a third-party tool.

A Claude Pro/Max subscription (the kind that powers Claude Code and the Claude apps) is not usable here: that authentication is licensed for Anthropic's own first-party clients, and routing it through a custom server would violate Anthropic's Consumer Terms — the "$200 of Claude usage from another service" concern you raised. So: API key it is. (If you run an Anthropic-compatible gateway, point base_url at it — see Configuration.)

Tools

Tool	Description
chat	Send a message to Claude. Supports multi-turn history, a system prompt, model selection, and extended thinking via thinking_budget.
chat_with_vision	Analyse an image given an image URL and a text prompt.
chat_with_search	Chat with live web search — Claude searches server-side and answers with cited sources.
list_models	List available Claude models and their IDs (cached for 5 minutes).

Note: Anthropic has no embeddings endpoint (they recommend Voyage AI), so unlike the grok/gpt servers there is no embedding tool.

chat

Name	Type	Required	Description
prompt	string	yes	The user message to send
system_prompt	string	no	System prompt to set context/behaviour
messages	string	no	Conversation history as a JSON array of {role, content} objects (roles: user/assistant only — use system_prompt for system instructions)
model	string	no	Model ID (default: server default, claude-opus-4-8). Call list_models.
temperature	float	no	Sampling temperature (0.0–1.0). Ignored when thinking_budget is set.
max_tokens	integer	no	Max tokens to generate (defaults to the server default)
thinking_budget	integer	no	Enable extended thinking with this token budget (min 1024). Reasoning is returned in a [thinking] block; max_tokens is auto-raised above the budget.

chat_with_vision

Name	Type	Required	Description
prompt	string	yes	Text prompt describing what to analyse
image_url	string	yes	URL of the image (must be http:// or https://)
model	string	no	Vision-capable model ID (default: server default)
temperature	float	no	Sampling temperature (0.0–1.0)
max_tokens	integer	no	Max tokens to generate

chat_with_search

Name	Type	Required	Description
prompt	string	yes	The user message
system_prompt	string	no	System prompt
model	string	no	Model ID (default: server default)
temperature	float	no	Sampling temperature (0.0–1.0)
max_tokens	integer	no	Max tokens to generate
max_uses	integer	no	Max web searches Claude may run for this request (default: 5)

Web search is billed by Anthropic at $10 per 1,000 searches on top of token costs, and an org admin must enable web search in the Claude Console.

list_models

No parameters. Results cached for 5 minutes.

Prerequisites

• Rust (edition 2024)
• An Anthropic API key from console.anthropic.com

Setup

mkdir -p ~/.config/mcp-server-claude-chat
cp config.toml.example ~/.config/mcp-server-claude-chat/config.toml
# then edit it and set api_key

Config (~/.config/mcp-server-claude-chat/config.toml):

api_key = "sk-ant-..."

# Optional:
# base_url = "https://api.anthropic.com/v1"   # or a compatible gateway
# default_model = "claude-opus-4-8"
# default_max_tokens = 4096

The server fails fast at startup if the config is missing or api_key is empty.

Build

cargo build --release   # produces target/release/claude-chat
cargo build             # debug build
cargo run               # run in dev mode
RUST_LOG=debug cargo run
cargo test              # unit tests (response formatting, validation, message building)

MCP Configuration

Claude Desktop (~/.config/Claude/claude_desktop_config.json) or any MCP client:

{
  "mcpServers": {
    "claude-chat": {
      "command": "/media/codechap/4TB/develop/mcps/mcp-server-claude-chat/target/release/claude-chat"
    }
  }
}

Claude Code:

claude mcp add claude-chat -- /media/codechap/4TB/develop/mcps/mcp-server-claude-chat/target/release/claude-chat

Project Structure

src/
  main.rs    - entry point, config loading, stdio transport setup
  server.rs  - MCP tool definitions (chat, chat_with_vision, chat_with_search, list_models)
  api.rs     - Anthropic HTTP client, Messages/Models types, response formatter
  params.rs  - tool parameter types with serde + JSON Schema derives
  config.rs  - TOML config loading

License

MIT