@sveltejs/opencode

OpenCode plugin for Svelte that provides the Svelte MCP server, a specialized file editor subagent and instruction files.

Installation

Add @sveltejs/opencode to your OpenCode config (either global or local):

{
	"$schema": "https://opencode.ai/config.json",
	"plugin": ["@sveltejs/opencode"]
}

That's it! You now have the Svelte MCP server and the file editor subagent configured automatically.

Features

Svelte MCP Server

The plugin automatically configures the Svelte MCP server which provides:

• list-sections - Discover available Svelte 5 and SvelteKit documentation sections
• get-documentation - Retrieve full documentation content for specific sections
• svelte-autofixer - Analyze Svelte code and get issues/suggestions
• playground-link - Generate Svelte Playground links with provided code

Svelte File Editor Subagent

A specialized subagent (svelte-file-editor) that is automatically used when creating, editing, or reviewing .svelte, .svelte.ts, or .svelte.js files. It fetches relevant documentation and validates code using the Svelte MCP server tools.

Agent Instructions

The plugin injects instructions that teach the agent how to effectively use the Svelte MCP tools.

Configuration

Create svelte.json to customize how the plugin configures MCP, the Svelte subagent, instructions, and skills.

{
	"$schema": "https://svelte.dev/opencode/schema.json",
	"mcp": {
		"type": "remote",
		"enabled": true
	},
	"subagent": {
		"enabled": true,
		"agents": {
			"svelte-file-editor": {
				"model": "anthropic/claude-sonnet-4-20250514",
				"temperature": 0.7,
				"top_p": 0.9,
				"maxSteps": 20
			}
		}
	},
	"instructions": {
		"enabled": true
	},
	"skills": {
		"enabled": ["svelte-code-writer", "svelte-core-bestpractices"]
	}
}

Defaults

If omitted, the plugin uses these defaults:

• mcp.type: "remote"
• mcp.enabled: true
• subagent.enabled: true
• subagent.agents: {}
• instructions.enabled: true
• skills.enabled: true

Configuration Options

| Option | Type | Default | Description | | ------------------------------------------------ | --------------------- | ---------- | ---------------------------------------------------------------------------------------------- | | mcp.type | "remote" \| "local" | "remote" | Use https://mcp.svelte.dev/mcp (remote) or run @sveltejs/mcp via npx (local). | | mcp.enabled | boolean | true | Enable or disable the Svelte MCP server entry. | | subagent.enabled | boolean | true | Enable or disable registration of the svelte-file-editor subagent. | | subagent.agents.svelte-file-editor.model | string | main agent | Override the model used by the Svelte file editor subagent. | | subagent.agents.svelte-file-editor.temperature | number | unset | Set temperature for the subagent. | | subagent.agents.svelte-file-editor.top_p | number | unset | Set top-p sampling for the subagent. | | subagent.agents.svelte-file-editor.maxSteps | number | unlimited | Limit the number of steps the subagent can execute. | | instructions.enabled | boolean | true | Enable or disable automatic instruction-file injection. | | skills.enabled | boolean \| string[] | true | Enable all skills (true), disable all skills (false), or enable only specific skill names. |

Supported Skill Names

When using skills.enabled as an array, these built-in names are currently available:

• svelte-code-writer
• svelte-core-bestpractices

Config File Locations and Precedence

The plugin reads from these files (lowest priority first, highest priority last):

• ~/.config/opencode/svelte.json
• $OPENCODE_CONFIG_DIR/svelte.json (when OPENCODE_CONFIG_DIR is set)
• .opencode/svelte.json in the current project

If the same key is defined in multiple files, the later location overrides earlier ones.

License

MIT