Python subprocess SDK for driving DeepSeek Harness over JSON-RPC stdio. The runtime inherits normal DeepSeek Harness environment variables such as DEEPSEEK_BASE_URL and DEEPSEEK_API_KEY, so callers can use real model endpoints directly or point those variables at a local proxy during benchmark runs.

By default, the SDK launches the bundled single-file dsh-jsonrpc-agent executable from the deepseek-harness-runtime-bin package and injects that package's default configuration (the stdio JSON-RPC server, agent core, preloaded DeepSeek adapter, JSONL session persistence, local bash) via DSH_CORDIS_CONFIG. To run a plugin composition of your own, keep the @deepseek-ai/dsh-jsonrpc entry in the config and pass the Cordis config path.

from deepseek_harness import DeepSeekHarness

with DeepSeekHarness(
    model="deepseek-v4-flash",
    cordis="examples/dsbench-coding-agent/cordis.yml",
) as harness:
    result = harness.run("Make the requested code change.")

TurnResult.final_response is the text content from the last assistant/message event in the turn. Use TurnResult.events for the complete event stream, including intermediate assistant messages and tool activity.

The same behavior can be selected for the runtime subprocess with DSH_CORDIS_CONFIG. The injection lives in HarnessClient.start(), so the low-level client's default launch gets it too: when the launch resolves to the bundled runtime and neither cordis nor a non-empty DSH_CORDIS_CONFIG is set (the runtime treats an empty value as absent, and so does the injection check), the bundled default configuration is used; an explicit runtime_bin or launch_args_override disables the injection entirely. See the sdk-runtime README for the runtime carriers (production exe vs dev-only node closure) and how to obtain them.