OmniRoute/docs/plugins/PLUGIN_SDK.md

OmniRoute Plugin SDK

Quick Start

import { definePlugin } from "omniroute/plugins/sdk";

export default definePlugin({
  name: "my-plugin",
  priority: 50,
  onRequest: async (ctx) => {
    console.log(`Request ${ctx.requestId} for ${ctx.model}`);
  },
  onResponse: async (ctx, response) => {
    console.log(`Response for ${ctx.requestId}`);
    return response;
  },
  onError: async (ctx, error) => {
    console.error(`Error: ${error.message}`);
  },
});

API Reference

definePlugin(def: PluginDefinition): Plugin

Factory function that creates a Plugin object with defaults.

Parameters:

• name (string, required) — Plugin name in kebab-case
• priority (number, optional, default: 100) — Lower runs first
• enabled (boolean, optional, default: true) — Start enabled?
• onRequest (function, optional) — Runs before chat handler
• onResponse (function, optional) — Runs after chat handler
• onError (function, optional) — Runs on handler error

blockRequest(response?): BlockingHookResult

Block the request and optionally return a custom response.

onRequest: (ctx) => {
  if (!ctx.headers["authorization"]) {
    return blockRequest({ error: "Unauthorized", status: 401 });
  }
};

modifyBody(body): PluginResult

Modify the request body before it reaches the provider.

onRequest: (ctx) => {
  return modifyBody({ ...ctx.body, temperature: 0.7 });
};

addMetadata(metadata): PluginResult

Attach metadata to the request context.

onRequest: (ctx) => {
  return addMetadata({ source: "my-plugin", version: "1.0.0" });
};

Plugin Context (PluginContext)

Field	Type	Description
requestId	string	Unique request identifier
model	string	Requested model name
provider	string	Target provider ID
body	Record<string, unknown>	Request body
headers	Record<string, string>	Request headers
metadata	Record<string, unknown>	Mutable metadata
timestamp	number	Request timestamp

Manifest (plugin.json)

{
  "name": "my-plugin",
  "version": "1.0.0",
  "description": "A sample plugin",
  "author": "your-name",
  "main": "index.js",
  "hooks": {
    "onRequest": { "enabled": true, "priority": 50 },
    "onResponse": true,
    "onError": false
  },
  "requires": {
    "permissions": ["network", "file-read"]
  },
  "enabledByDefault": false,
  "configSchema": {
    "apiKey": { "type": "string", "description": "API key for external service" },
    "maxRetries": { "type": "number", "min": 1, "max": 10, "default": 3 },
    "debug": { "type": "boolean", "default": false },
    "mode": { "type": "string", "enum": ["fast", "slow"], "default": "fast" }
  }
}

Hook Priority

Hooks can be configured with priority (lower = runs first):

{
  "hooks": {
    "onRequest": { "enabled": true, "priority": 10 },
    "onResponse": { "enabled": true, "priority": 100 }
  }
}

Or as simple booleans (default priority 100):

{
  "hooks": {
    "onRequest": true,
    "onResponse": true
  }
}

Permission System

Plugins run in a sandboxed VM context. Access to external resources requires explicit permissions:

Permission	Grants
network	fetch, AbortController, Headers, Request, Response
file-read	fs.readFile, fs.readdir, fs.stat
file-write	fs.writeFile, fs.mkdir, fs.rm
env	Read-only process.env proxy
exec	child_process.exec, child_process.execSync

Without a permission, the corresponding globals are simply not available in the sandbox.

Config Schema

Define configurable settings in configSchema:

{
  "configSchema": {
    "apiKey": { "type": "string", "description": "External API key" },
    "maxRetries": { "type": "number", "min": 1, "max": 10, "default": 3 },
    "debug": { "type": "boolean", "default": false },
    "mode": { "type": "string", "enum": ["fast", "slow"], "default": "fast" }
  }
}

Field types: string, number, boolean, select

Field options: default, min, max, enum, description

Config values are persisted in the database and accessible via the dashboard config page.

Built-in Events

Event	When	Payload
onRequest	Before chat handler	Request context
onResponse	After chat handler	Response data
onError	On handler error	Error object
onModelSelect	Model selected for routing	Model info
onComboResolve	Combo routing resolved	Combo targets
onRateLimit	Rate limit hit	Limit info
onQuotaExhaust	Quota exhausted	Quota info
onProviderError	Provider returned error	Error details
onStreamStart	SSE stream started	Stream info
onStreamEnd	SSE stream ended	Stream stats

Examples

Request Logger

import { definePlugin } from "omniroute/plugins/sdk";

export default definePlugin({
  name: "request-logger",
  onRequest: async (ctx) => {
    console.log(`[${new Date().toISOString()}] ${ctx.method} ${ctx.model} -> ${ctx.provider}`);
  },
});

Rate Limiter

import { definePlugin, blockRequest } from "omniroute/plugins/sdk";

const requests = new Map<string, number[]>();

export default definePlugin({
  name: "rate-limiter",
  priority: 10,
  onRequest: async (ctx) => {
    const key = ctx.headers["x-api-key"] || "anonymous";
    const now = Date.now();
    const window = 60000; // 1 minute
    const maxRequests = 100;

    const timestamps = (requests.get(key) || []).filter(t => t > now - window);
    timestamps.push(now);
    requests.set(key, timestamps);

    if (timestamps.length > maxRequests) {
      return blockRequest({ error: "Rate limit exceeded", status: 429 });
    }
  },
});

Response Transformer

import { definePlugin } from "omniroute/plugins/sdk";

export default definePlugin({
  name: "response-transformer",
  onResponse: async (ctx, response) => {
    if (response.choices) {
      response.choices = response.choices.map((c: any) => ({
        ...c,
        message: { ...c.message, content: c.message.content.trim() },
      }));
    }
    return response;
  },
});