dsh-sample-plugin

A minimal, verified sample of writing plugins for DeepSeek Harness ("everything is a plugin"). Not official — just a community example that runs.

Two plugins, one composition:

• src/tool-hash-sum.ts — a model-callable hash_sum tool (sha256/sha1/md5 over text or file). Follows the defineTool contract from the official docs: typed parameters, canonical JSON output, model-facing render, exec.signal cancellation.
• src/result-logger.ts — a hook plugin observing the documented tools/result extension point, counting every final outcome without touching dispatch.

Verified, not "should work"

End-to-end run against the real service stack (Timer + SystemPrompt + ToolRegistry, same as the harness's own test helpers), 8/8 checks pass:

#	Check	Result
1	schemas() model-facing projection	pass
2	canonical JSON value + render output	pass
3	known-answer check: sha256("abc") = ba7816bf…15ad	pass
4	file hashing via exec.signal-aware I/O	pass
5	cross-field validation (exactly one of text/path) contained as isError	pass
6	unsupported algorithm contained, no crash	pass
7	tools/result hook observed 5/5 outcomes	pass
8	effect-based unregistration (dispose removes tool)	pass

Run it

npm install
node --import tsx verify.ts

Node 22+. Dependencies resolve from npm: @deepseek-ai/cordis, @deepseek-ai/dsh-tools, @deepseek-ai/dsh-system-prompt, @deepseek-ai/cordis-plugin-timer. No API key needed — the sample runs keylessly, same as the official Cordis tutorial.

Three gotchas worth knowing (learned the hard way)

1. output.schema is a DSL, not raw JSON Schema (ValueSchemaSpec): object nodes must declare additionalProperties, required is only supported on parameter properties, and type: 'json' exists only in the DSL.
2. Raw registry.register() validates against plain JSON Schema instead — where type: 'json' is not a thing.
3. registry.execute() requires a caller signal — the registry reads callerSignal unconditionally.

License

MIT. Third-party packages used under MIT / BSD-3-Clause — see THIRD_PARTY_NOTICES.md.

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Built as a first-contribution probe for the dsh plugin ecosystem. Feedback welcome: hcac4735@agent.qq.com · GitHub @chenhz01

Collaboration

Everything in this repo is free to use — no locked layers, no upsell.

• Free: this sample, its verification script, and the three gotchas above. Copy them.
• Custom plugin development: I take paid engagements building production dsh plugins (tools, hooks, protocol bridges). Two things to include in an email: what your harness deployment needs, and your timeline.
• Not offered: opinions on DeepSeek's roadmap — that's their court, not mine.

If you're deciding whether to email: the verification table above is the quality bar. If it looks like your bar, we'll probably get along.