Your First DeepSeek Harness Plugin: Mount It Before You Productize

What a plugin actually is

In the official tutorial, a plugin is a TypeScript module that exports apply. The framework calls apply with a ctx so you can register capabilities. The minimum shape:

```ts import type { Context } from '@deepseek-ai/cordis'

export const name = 'hello-plugin'

export function apply(ctx: Context) { console.log('[hello-plugin] plugin loaded!') } ```

That is the complete configuration. Do not start by adding tools, swapping models or calling external APIs.

Official order

1. Start from a repository checkout that already built from source.
2. Create a local plugin file.
3. Insert it with a cordis.yml overlay. The plugin path must be absolute.
4. Boot the Web UI with that overlay and check the load log.

Exact commands and YAML fields belong to the official tutorial — field names will move in preview.

After it loads

Do not turn the first plugin into a do-everything agent. Pick one seam from the official architecture table:

• A human command only: ctx.commands
• One narrow model-facing tool: ctx.tools
• A model provider: ctx.llm

Tag the plugin repo with the GitHub topic dsh-plugin. That is how the official README wants plugins discovered.

Safety

Plugins can reach the filesystem, subprocesses and credentials. Local experiments can be wide. Before you give a plugin to someone else, narrow permissions. Do not hard-code secrets. Do not open an arbitrary shell by default.

FAQ

Why did the plugin not load?

The official tutorial insists on an absolute path. A patch file contributes configuration; it does not change the directory the loader resolves modules from.

Should I publish an npm package?

Get a local overlay working first. Publish only after you follow the official plugin-distribution notes, and add the dsh-plugin topic.

Official source: Your first plugin. This article is a boundary and sequence companion, not a replacement for the tutorial's YAML and launch commands.