DeepSeek MCP Server

An MCP (Model Context Protocol) server that lets Claude Code delegate tasks to DeepSeek, saving you 10-50x on API costs for routine coding tasks.

Why This Exists

The Problem: Claude is expensive. Running Claude Opus for every file read, code generation, or refactoring task adds up fast.

The Solution: Delegate routine tasks to DeepSeek (which costs ~$0.14/M input tokens vs Claude's $3-15/M) while keeping Claude for complex reasoning and coordination.

Cost Comparison

| Model | Input (per 1M tokens) | Output (per 1M tokens) | |-------|----------------------|------------------------| | Claude Opus | $15.00 | $75.00 | | Claude Sonnet | $3.00 | $15.00 | | DeepSeek Chat | $0.14 | $0.28 | | DeepSeek Reasoner | $0.55 | $2.19 |

Real example: A coding session with 50 file operations might cost $5-10 with Claude. With DeepSeek handling the file operations: ~$0.20.

Features

This MCP server provides 4 tools to Claude:

1. deepseek_agent - Agentic File Operations

Full coding agent with tool access. Use for tasks requiring file system interaction.

Sub-tools available:

• read_file - Read file contents
• write_file - Create/overwrite files
• edit_file - Find-and-replace in files
• run_bash - Execute shell commands
• glob - Find files by pattern
• grep - Search file contents
• list_dir - List directory contents
• web_search - Search the web (requires Brave API key)

Example:

Use deepseek_agent to refactor all the error handling in src/ to use a custom AppError class

2. deepseek_chat - Fast Chat Completion

Simple prompt → response. No tools, no overhead. Use for analysis, explanations, code review.

Example:

Use deepseek_chat to explain what this regex does: ^(?=.*[A-Z])(?=.*\d).{8,}$

3. web_fetch - Fetch & Analyze Web Pages

Fetches a URL, extracts content, answers questions about it. Cheaper than Claude's built-in WebFetch.

Example:

Use web_fetch to get the main features from https://docs.python.org/3/whatsnew/3.12.html

4. web_search - Web Search with Synthesis

Searches Brave, synthesizes results with DeepSeek. Requires BRAVE_API_KEY.

Example:

Use web_search to find the latest TypeScript 5.4 features

Installation

Prerequisites

• Node.js 20+ - Download
• Claude Code CLI - Installation guide
• DeepSeek API key (required) - Get one here (~$0.14/M tokens)
• Brave Search API key (optional, for web_search) - Get one here (free tier available)

Step 1: Clone and Build

git clone https://github.com/luongjames8/deepseek-mcp-server.git
cd deepseek-mcp-server
npm install
npm run build

Step 2: Configure Claude Code

Edit your Claude config file:

Location:

• Windows: %USERPROFILE%\.claude.json
• Mac/Linux: ~/.claude.json

Add to the mcpServers section:

{
  "mcpServers": {
    "deepseek": {
      "command": "node",
      "args": ["/absolute/path/to/deepseek-mcp-server/dist/index.js"],
      "env": {
        "DEEPSEEK_API_KEY": "your-deepseek-api-key"
      }
    }
  }
}

Important: Use the absolute path to dist/index.js. Examples:

• Windows: "C:/Users/YourName/deepseek-mcp-server/dist/index.js"
• Mac: "/Users/yourname/deepseek-mcp-server/dist/index.js"
• Linux: "/home/yourname/deepseek-mcp-server/dist/index.js"

Optional: Add Brave API key for web search:

"env": {
  "DEEPSEEK_API_KEY": "your-deepseek-api-key",
  "BRAVE_API_KEY": "your-brave-api-key"
}

Step 3: Restart Claude Code

Run /mcp in Claude Code to restart the MCP servers. You should see deepseek in the list.

Alternative: Environment File

Instead of putting keys in ~/.claude.json, create a .env file in the project:

cp .env.example .env
# Edit .env with your API keys

Usage

Once installed, Claude can use the tools directly:

# File operations
Use deepseek_agent to read all .ts files in src/ and add JSDoc comments to exported functions

# Quick questions
Use deepseek_chat to explain the difference between Promise.all and Promise.allSettled

# Web research
Use web_fetch to summarize https://react.dev/blog/2024/02/15/react-labs-what-we-have-been-working-on-february-2024

# Web search
Use web_search for "Node.js 22 new features"

Recommended Workflow

1. Use Claude for: Planning, architecture decisions, complex debugging, multi-step coordination
2. Delegate to DeepSeek for: File reading/writing, code generation, refactoring, simple explanations, web fetching

Tool Selection Guide

| Task | Tool | Why | |------|------|-----| | Read/write files | deepseek_agent | Full file system access | | Generate boilerplate | deepseek_agent | Can write files directly | | Explain code | deepseek_chat | Fast, no overhead | | Code review | deepseek_chat | Analysis only | | Fetch documentation | web_fetch | Cheaper than Claude | | Research current topics | web_search | Real-time web access |

Configuration

Edit config.yaml to customize behavior:

# Model settings
model:
  default: "deepseek-chat"
  allowed:
    - "deepseek-chat"
    - "deepseek-reasoner"  # Better for complex reasoning

# Agent limits
agent:
  max_iterations: 50       # Max tool calls per task
  timeout_seconds: 300     # 5 minute timeout

# Tool settings
tools:
  bash:
    default_timeout: 120   # 2 minutes per command
    max_timeout: 600       # 10 minute max

Limitations

What DeepSeek is Good At

• Routine file operations
• Code generation from clear specs
• Refactoring with explicit instructions
• Answering factual questions
• Summarizing content

What Claude is Better At

• Complex multi-step reasoning
• Ambiguous requirements
• Architecture decisions
• Nuanced code review
• Tasks requiring judgment

Technical Limitations

• Path sandboxing: File operations are restricted to the working directory
• No interactive commands: Can't run commands that require user input
• Web search latency: 10-30 seconds (Brave API + synthesis)
• Context limits: DeepSeek has smaller context than Claude

Troubleshooting

"DEEPSEEK_API_KEY is required"

Set the API key in ~/.claude.json env section or in .env file.

Tools not appearing in Claude

1. Check /mcp output for errors
2. Verify the cwd path is correct and absolute
3. Make sure npm run build completed successfully

"Path escape attempt blocked"

The agent tried to access files outside the working directory. This is a security feature.

Slow web_search

Web search has inherent latency (10-30s). For faster results:

• Use web_fetch if you know the exact URL
• Use Claude's built-in WebSearch for time-sensitive queries

Security

• Path sandboxing: All file operations are restricted to the specified working directory
• No credential storage: API keys are passed via environment variables
• No network access from agent tools: Only explicit web_fetch/web_search can access the internet

License

MIT

Contributing

PRs welcome! Please ensure:

1. npm run build succeeds
2. Test all 4 tools manually
3. Update README if adding features