dsh-llm-opencode

OpenCode Zen free model provider adapter for DeepSeek Harness (DSH).

Registers the opencode-zen provider route in DSH's LLM seam, giving your coding agent access to OpenCode Zen's free-tier models — no API key required for free models, no credit card, no setup friction.

Free Models

Model	ID	Context	Max Output	Notes
DeepSeek V4 Flash Free	deepseek-v4-flash-free	200K	128K	DeepSeek's V4 Flash, SWE-bench ~79%
Nemotron 3 Ultra Free	nemotron-3-ultra-free	1M	128K	NVIDIA's flagship, huge context
MiMo V2.5 Free	mimo-v2.5-free	200K	32K	Xiaomi's coding model
Big Pickle	big-pickle	200K	128K	Stealth general-purpose model

Free models are served through OpenCode Zen's public gateway. Availability may change; the adapter auto-discovers models tagged free from the /models endpoint.

Install

# Into a DSH web profile
dsh plugin --profile web add dsh-llm-opencode

# Or from GitHub directly
dsh plugin --profile web add "github:bobowsh/dsh-llm-opencode#main"

How It Works

This plugin implements the LlmAdapter interface from @deepseek-ai/dsh-llm and registers a single provider route opencode-zen. When DSH routes a request to this provider:

1. Serialization — harness messages are translated to OpenAI-compatible chat completions (text-only; images are rejected with UNSUPPORTED_CONTENT).
2. Streaming — SSE responses are parsed via eventsource-parser and translated into harness StreamChunk events (block-start, text-delta, reasoning-delta, tool-call-delta, usage, finish).
3. Identity — requests carry User-Agent: opencode/1.0.0 and related headers to satisfy OpenCode Zen's client identity check (the default deepseek-harness/... user-agent is rejected by the gateway).
4. Credentials — resolves the API key from DSH's credential store (env var OPENCODE_API_KEY) or the ambient environment. Free models work without a key; paid models require one.
5. Model discovery — registers a discovery handler that fetches /models from the gateway and filters for free-tagged entries.

Configuration

The adapter is configurable through DSH's settings system (llm-opencode section in settings.yaml). Changes take effect immediately without restart.

Setting	Default	Description
baseURL	https://opencode.ai/zen/v1	Gateway endpoint
apiKeyEnv	OPENCODE_API_KEY	Credential store key for the API token
maxTokens	128000	Default max output tokens per request
defaultContextWindow	1000000	Fallback context window for unknown models
streamIdleTimeoutMs	300000	Max idle time (ms) before stream is considered dead
models	(built-in catalog)	Override the model catalog
retryPolicy	(built-in)	Retry behavior for transient errors

Example settings.yaml snippet

llm-opencode:
  baseURL: "https://opencode.ai/zen/v1"
  maxTokens: 64000
  models:
    - id: deepseek-v4-flash-free
      name: DeepSeek V4 Flash Free
      contextWindow: 200000
      maxTokens: 128000

Bundle Patch

The included cordis.patch.yml registers the llm-opencode plugin row into the DSH bundle loader, so the plugin is auto-loaded when installed into a profile.

Requirements

• DeepSeek Harness >= 0.1.0-rc.7
• @deepseek-ai/cordis ^4.0.1 (peer dependency)

License

MIT