deepseek-harness/docs/user/guide/quickstart.md

Quick start

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This guide gets an agent running in five minutes.

Prerequisites

• Node.js ^22.19 or >= 24
• pnpm 11 (use Corepack to select the repository-pinned version)

# Check versions
node -v   # v22.19.x, or v24.x and newer
corepack enable
pnpm -v   # 11.x

Step 1: run echo-agent

echo-agent needs no API key and runs after dependencies are installed.

# Clone the repository
git clone https://github.com/deepseek-harness/deepseek-harness.git
cd deepseek-harness

# Install dependencies
pnpm install

# Start echo-agent
pnpm run demo:echo

The process prints:

echo-agent ready. Type a message ("echo <text>" triggers the tool).
>

Enter:

> echo hello world

The model issues a tool call, and the echo tool returns the text in uppercase:

[tool call] echo({"text":"hello world"})
[tool result] ECHO: HELLO WORLD

Your local environment is ready.

Step 2: use a real model

Next, connect a real DeepSeek model and run the complete command-line agent.

Get an API key

Get an API key from DeepSeek Platform.

Configure the environment

Create a gitignored .env file in the repository root:

DEEPSEEK_API_KEY=sk-your-key-here

Start repl-agent

pnpm run demo:repl

agent REPL ready. Give it a coding task.
>

This is a complete coding assistant that can read and write files, run commands, and delegate subtasks.

Try a task:

> Create hello.js in the current directory, print "Hello from Harness!", and run it

What happened

echo-agent and repl-agent use the same application framework (@deepseek-ai/dsh-stdio-demo). Their cordis.yml files select different plugins and configuration. Custom agents use the same composition model.

Next steps

• Configuration — understand the cordis.yml format
• Develop a plugin — build your own tool or backend