# Harness SDK

Source: /

harness-sdk

GitHub

# harness-sdk.

The React client for agent harnesses. Bring Claude Code, Codex, or deepagents—keep one `useChat`-shaped API.

pnpm add harness-sdk

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Claude Code Codex deepagents

01 Familiar by design

Messages, status, sendMessage, stop.

02 Resumes by default

Snapshots, ordered commands, cumulative acks.

03 Durable on Python

Pinned objects keep agent state alive.