deepseek-harness/docs/user/guide/python-sdk.md

Get started with the Python SDK

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This tutorial installs the published Python SDK, runs the checked-in minimal profile overlay, and shows how to customize the same dsh profile from your own program.

Prerequisites

• Python 3.10 or newer
• Git
• Linux x64, Linux arm64, or macOS 14 or newer on arm64
• A DeepSeek-compatible API endpoint and credential
• An isolated workspace and an isolated Harness home

Install the SDK

git clone https://github.com/deepseek-ai/deepseek-harness.git
cd deepseek-harness
python -m venv .venv
. .venv/bin/activate
python -m pip install deepseek-harness-sdk

The installation includes a matching native runtime wheel and the dsh command. Normal SDK execution needs no system Node.js. Repository contributors who build the artifacts should use the Python contributor workflow.

Run the checked-in example

Export the credential and, when needed, a compatible proxy endpoint:

export DEEPSEEK_API_KEY=sk-your-key-here
# export DEEPSEEK_BASE_URL=http://127.0.0.1:8000/v1

Run one task with explicit workspace and home paths:

python examples/python-sdk-agent/minimal.py \
  --workspace /absolute/path/to/disposable-workspace \
  --dsh-home /absolute/path/to/example-dsh-home \
  --session-id example-001 \
  "Inspect the repository and fix the failing tests."

The script prints the final assistant response. The selected home receives the generated sdk profile, settings, credentials if you add them, installed plugins, and Zstandard session logs under sessions/. The example and SDK never silently read ~/.dsh.

Use the SDK in your program

from pathlib import Path

from deepseek_harness import DeepSeekHarness

workspace = Path("/absolute/path/to/disposable-workspace").resolve()
dsh_home = Path("/absolute/path/to/example-dsh-home").resolve()
patch = Path("examples/python-sdk-agent/minimal.patch.yml").resolve()

with DeepSeekHarness(
    provider="deepseek-official",
    model="deepseek-v4-flash",
    max_tokens=49_152,
    cwd=str(workspace),
    dsh_home=str(dsh_home),
    profile="sdk",
    patches=(str(patch),),
) as harness:
    result = harness.run(
        "Inspect the repository and fix the failing tests.",
        session_id="example-001",
    )

print(result.final_response)

The SDK starts the bundled dsh --profile sdk process lazily and reuses it until context-manager exit. The profile, its persistent patch, the home patch, and the ordered patches tuple form the application configuration. There is no separate Python runtime bin or complete-config option.

Install or define plugins

Use dsh plugin for dependencies and bundle layers that should persist in this home:

export DSH_HOME=/absolute/path/to/example-dsh-home
dsh --profile sdk --dump-default-config >/dev/null
dsh plugin --profile sdk add file:/absolute/path/to/my-plugin-bundle

The first command initializes the shipped SDK profile. The second forwards package management to pnpm, then records any installed package that exports a dsh.bundle layer. Install pnpm only for this management command; launching the installed SDK does not need it. Edit $DSH_HOME/profiles/sdk/cordis.patch.yml for persistent row changes, or pass patch files from Python for per-launch changes.

Another profile is valid when it includes @deepseek-ai/dsh-sdk-app or another JSON-RPC server row. Missing server rows, unresolved plugins, and invalid patches fail during startup instead of falling back to another composition.

Understand the minimal overlay

Property	Value
System prompt	DSH_SYSTEM_PROMPT, falling back to You are a helpful software engineer assistant.
Model in minimal.py	--model, then DSH_MODEL, then deepseek-v4-flash
Model-facing tools	Persistent bash and str_replace_editor only
Bash timeout	300 seconds
Editor output limit	16,000 characters
Context compaction	Disabled
Session persistence	Zstandard JSONL under <dsh_home>/sessions

The overlay allowlists persistent Bash and the editor for every SDK-created root agent, so later base-profile tools cannot appear implicitly. It suppresses unrelated prompt sections and runtime-context messages, disables local instruction discovery and compaction, and retains the SDK application's protocol, persistence, policy, settings, credentials, and providers. Persistent Bash and the editor can modify any path visible to the runtime, so use a disposable checkout or container. The PTY implementation makes this example POSIX-only.

Use a fresh home when profiles, plugins, credentials, settings, and sessions must be isolated. Use a fresh session id for independent work; reuse a harness, home, and id only to continue the same durable conversation and session-owned resources.

The example reference owns the checked-in overlay. The Python SDK reference covers lifecycle, results, notifications, and low-level behavior; the dsh CLI reference covers profile layering.