daisy-plugin-sdk

Tiny helper for authoring Daisy external plugins. Implements the four-endpoint HTTP contract (/manifest, /healthz, /readyz, /execute) so plugin authors only write execute(input, ctx).

Zero runtime dependencies — uses Node's built-in http server and global fetch.

Daisy

Daisy wiki

Quick start

mkdir my-plugin && cd my-plugin
npm init -y
npm install daisy-plugin-sdk

// manifest.json
{
  "name":          "my.plugin",
  "version":       "0.1.0",
  "description":   "Does the thing",
  "primaryOutput": "result",
  "inputSchema":   { "type": "object", "required": ["query"], "properties": { "query": { "type": "string" } } },
  "outputSchema":  { "type": "object", "properties": { "result": { "type": "string" } } },
  "configRefs":    []
}

// index.js
import { servePlugin } from "daisy-plugin-sdk";
import manifest from "./manifest.json" with { type: "json" };

servePlugin({
  manifest,
  async execute(input, ctx) {
    // ctx = { executionId, workspaceId, nodeName, config, deadlineMs, signal }
    return { result: `you said: ${input.query}` };
  },
});

Ship it as a container, expose port 8080, install with npm run install-plugin -- --endpoint http://my-plugin:8080.

Contract details

servePlugin(opts)

| Option | Required | Description | |----------|----------|-------------| | manifest | yes | Object matching the plugin manifest schema. | | execute | yes | async (input, ctx) => output \| { output, usage } | | readyz | no | async () => boolean — return false to make /readyz respond 503. Default: always true. | | port | no | Listen port. Default: PORT env or 8080. | | host | no | Bind host. Default: 0.0.0.0. | | log | no | (level, msg, meta) => void. Default: stdout/stderr JSON lines. |

ctx inside execute

{
  executionId: "uuid",    // the workflow execution that's running you
  workspaceId: "uuid",    // for scoping / audit
  nodeName:    "string",  // the DSL node that resolved to this plugin
  config:      { },       // plaintext values for configs declared in configRefs
  deadlineMs:  60000,     // wall-clock budget set by the engine
  signal:      AbortSignal // pass to fetch / pg / etc. for cooperative cancellation
}

When the engine times out OR the workflow user cancels, signal aborts. Pass it to any outbound call that supports AbortController and your plugin shuts down its work cleanly instead of running detached for another N seconds.

Return value

Either:

return { result: "..." };                       // whole object is the output
// or
return { output: { result: "..." }, usage: {} }; // explicit

The engine validates against outputSchema from the manifest. A return that doesn't match throws on the engine side.

Errors

Throwing inside execute() produces a 500 response with { error: "<message>" }. The engine surfaces these as node failures and applies its retry / timeout / self-heal policies.

Example: real plugin

See plugins-external/reddit/ in the Daisy repo — a real external plugin in ~25 lines of code using this SDK.

What's NOT in this SDK (yet)

• Streaming. /execute is synchronous request/response in Phase 1+2. Streaming hooks (ctx.stream.text(...)) come in Phase 3 via a server-sent-events callback URL.
• Auto-registration. Plugins still install via the engine's CLI / admin UI. The SDK doesn't try to call back to the engine.
• Schema validation. The engine validates input/output against the manifest schemas. The SDK trusts what comes in and what execute() returns.