@opticlm/connector

[!WARNING] This library is intended solely for implementing Optic's Extension functionality and has not been designed with reliability in mind for other purposes.

Provides an abstract interface that allows LLMs to connect to fact sources such as LSPs, code diagnostics, symbol definitions/references, links, and frontmatter; includes both an MCP implementation and a Vercel AI SDK implementation.

Table of Contents

• Installation
• MCP Quick Start
• AI SDK Quick Start
• MCP Tools
• AI SDK Tools
• Tool Callbacks
• MCP Resources
• Auto-Complete for File Paths
• Subscription and Change Notifications
• Symbol Resolution
• Pipe IPC (Out-of-Process)
• LSP Client (Built-in)
• Requirements
• License

Installation

npm install @opticlm/connector
# or
pnpm add @opticlm/connector

MCP Quick Start

Providers are installed onto an MCP server using install() from @opticlm/connector/mcp. Each call registers the tools and resources for that specific provider. Providers that depend on file access (definition, references, hierarchy, edit) receive a fileAccess option.

You can pass a single provider or an array of providers of the same type. When an array is given, their results are merged automatically — array-returning methods (e.g. provideDefinition) are concatenated, void methods are called on all providers in parallel.

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'
import { install } from '@opticlm/connector/mcp'
import * as fs from 'fs/promises'

// 1. Create your MCP server
const server = new McpServer({
  name: 'my-ide-mcp-server',
  version: '1.0.0'
})

// 2. Implement File Access
const fileAccess = {
  readFile: async (uri: string) => {
    return await fs.readFile(uri, 'utf-8')
  },
  readDirectory: (uri: string) => yourIDE.workspace.readDirectory(uri),
  isFile: ...,
  isDirectory: ...,
}

// 3. Implement Edit Provider
const edit = {
  // Show diff in your IDE and get user approval
  applyEdits: async (operation) => {
    // ...
  },
}

// 4. Implement LSP Capability Providers
const definition = {
  provideDefinition: async (uri, position) => {
    return await lspClient.getDefinition(uri, position)
  },
}

const diagnostics = {
  provideDiagnostics: async (uri) => {
    return await lspClient.getDiagnostics(uri)
  },
  getWorkspaceDiagnostics: async () => {
    return await lspClient.getWorkspaceDiagnostics()
  },
}

const outline = {
  provideDocumentSymbols: async (uri) => {
    return await lspClient.getDocumentSymbols(uri)
  },
}

// 5. Install providers onto the server
//    fileAccess is installed first; others receive it as an option when needed
install(server, fileAccess)
install(server, edit, { fileAccess })
install(server, definition, { fileAccess })
install(server, diagnostics, { fileAccess })
install(server, outline, { fileAccess })

// You can also pass an array to merge multiple providers of the same type:
// install(server, [definition, anotherDefinition], { fileAccess })
// install(server, [diagnostics, anotherDiagnostics], { fileAccess })

// 6. Connect to transport (you control the server lifecycle)
const transport = new StdioServerTransport()
await server.connect(transport)

Each install() call is independent — only install the providers your IDE actually supports. The fileAccess option is required for providers that read files (edit, definition, references, hierarchy) and is used optionally by others for path auto-complete.

AI SDK Quick Start

The @opticlm/connector/ai-sdk entry point exports typed tool factories for the Vercel AI SDK. Each factory takes the required providers and returns a tool that can be passed directly to generateText, streamText, or useChat.

Resources from the MCP implementation are replaced by explicit tool calls that accept the same parameters as query arguments.

import { generateText } from 'ai'
import { openai } from '@ai-sdk/openai'
import {
  gotoDefinition,
  findReferences,
  getDiagnostics,
  getWorkspaceDiagnostics,
  getOutline,
  requestFile,
  applyEdit,
  globalFind,
  getOutlinks,
  getBacklinks,
  getLinkStructure,
  addLink,
  getFrontmatter,
  getFrontmatterStructure,
  setFrontmatter,
} from '@opticlm/connector/ai-sdk'
import { SymbolResolver } from '@opticlm/connector'
import * as fs from 'fs/promises'

// 1. Set up providers
const fileAccess = {
  readFile: async (uri: string) => fs.readFile(uri, 'utf-8'),
  readDirectory: async (path: string) => yourIDE.readDirectory(path),
  isFile: ...,
  isDirectory: ...,
}
const edit = {
  applyEdits: async (operation) => yourIDE.applyEdits(operation),
}
const definition = {
  provideDefinition: async (uri, position) => lsp.getDefinition(uri, position),
}

// 2. Create a resolver (shared across tools)
const resolver = new SymbolResolver(fileAccess)

// 3. Build the tools object
const tools = {
  goto_definition: gotoDefinition(definition, resolver),
  apply_edit: applyEdit(edit, fileAccess),
  request_file: requestFile(fileAccess),
}

// 4. Use with any AI SDK call
const { text } = await generateText({
  model: openai('gpt-4o'),
  tools,
  messages: [{ role: 'user', content: 'Find all usages of MyClass' }],
})

// 5. Render typed tools in UI
import type { ConnectorTools } from '@opticlm/connector/ai-sdk'
import type { UIMessage, UIDataTypes } from 'ai'

type ChatMessage = UIMessage<unknown, UIDataTypes, ConnectorTools>

MCP Tools

The SDK automatically registers tools based on which providers you install:

goto_definition

Navigate to the definition of a symbol.

find_references

Find all references to a symbol.

find_file_references

Find all references to a file across the workspace (e.g., all files that import or link to the given file).

Only registered when your ReferencesProvider implements the optional provideFileReferences method.

call_hierarchy

Get call hierarchy for a function or method.

apply_edit

Apply a text edit to a file using hashline references (requires user approval).

The files:// resource returns file content in hashline format — each line is prefixed with <line>:<hash>|, where the hash is a 2-char CRC16 digest of the line's content. To edit a file, reference lines by these hashes. If the file has changed since the last read, the hashes won't match and the edit is rejected, preventing stale overwrites.

global_find

Search for text across the entire workspace.

get_link_structure

Get all links in the workspace, showing relationships between documents.

add_link

Add a link to a document by finding a text pattern and replacing it with a link.

get_frontmatter_structure

Get frontmatter property values across documents.

set_frontmatter

Set a frontmatter property on a document.

AI SDK Tools

The AI SDK implementation provides the same capabilities as the MCP tools. Resources from MCP become explicit tool calls that accept their parameters directly.

Navigation & References

| Tool factory | Tool name | Description | |---|---|---| | gotoDefinition(provider, resolver) | goto_definition | Navigate to a symbol's definition | | gotoTypeDefinition(fn, resolver) | goto_type_definition | Navigate to a symbol's type definition | | findReferences(provider, resolver) | find_references | Find all references to a symbol | | findFileReferences(fn) | find_file_references | Find all imports/links to a file | | callHierarchy(provider, resolver) | call_hierarchy | Incoming or outgoing call hierarchy |

Optional tools (gotoTypeDefinition, findFileReferences) take the provider method directly — only create them if your provider supports it:

// Only add if your provider has provideTypeDefinition
if (definition.provideTypeDefinition) {
  tools.goto_type_definition = gotoTypeDefinition(definition.provideTypeDefinition, resolver)
}

Editing

| Tool factory | Tool name | Description | |---|---|---| | applyEdit(provider, fileAccess) | apply_edit | Apply a hash-verified edit to a file | | requestFile(fileAccess) | request_file | Read a file (hashline format) or list a directory |

requestFile replaces the files:// MCP resource. It accepts optional start_line, end_line, and pattern parameters instead of URI fragments/query strings:

// Read full file
{ path: 'src/index.ts' }

// Read lines 10–20
{ path: 'src/index.ts', start_line: 10, end_line: 20 }

// Filter to import lines only
{ path: 'src/index.ts', pattern: '^import' }

Diagnostics

| Tool factory | Tool name | Description | |---|---|---| | getDiagnostics(provider) | get_diagnostics | Get diagnostics for a specific file | | getWorkspaceDiagnostics(fn) | get_workspace_diagnostics | Get diagnostics across the workspace |

Returns structured { diagnostics: Diagnostic[] } — the full diagnostic objects, not markdown text.

Outline

| Tool factory | Tool name | Description | |---|---|---| | getOutline(provider) | get_outline | Get document symbols (outline) for a file |

Returns structured { symbols: DocumentSymbol[] } with the full nested symbol tree.

Graph / Links

| Tool factory | Tool name | Description | |---|---|---| | getOutlinks(provider) | get_outlinks | Get outgoing links from a file | | getBacklinks(provider) | get_backlinks | Get incoming links (backlinks) to a file | | getLinkStructure(provider) | get_link_structure | Get all links in the workspace | | addLink(provider) | add_link | Add a link to a document |

Frontmatter

| Tool factory | Tool name | Description | |---|---|---| | getFrontmatter(provider) | get_frontmatter | Get all frontmatter for a file | | getFrontmatterStructure(provider) | get_frontmatter_structure | Query a frontmatter property across documents | | setFrontmatter(provider) | set_frontmatter | Set a frontmatter property (use null to remove) |

Search

| Tool factory | Tool name | Description | |---|---|---| | globalFind(provider) | global_find | Search for text across the workspace |

Tool Callbacks

Each provider with tools accepts optional onInput and onOutput callbacks in its install options. These fire synchronously around each tool invocation — onInput before processing, onOutput after a successful result (not on errors).

Use them for logging, telemetry, or testing:

import { install } from '@opticlm/connector/mcp'

// EditProvider — apply_edit
install(server, editProvider, {
  fileAccess,
  onEditInput: (input) => {
    console.log('edit requested:', input.uri, input.description)
  },
  onEditOutput: (output) => {
    console.log('edit result:', output.success, output.message)
  },
})

// DefinitionProvider — goto_definition + goto_type_definition
install(server, definitionProvider, {
  fileAccess,
  onDefinitionInput: (input) => log('goto_definition', input),
  onDefinitionOutput: (output) => log('goto_definition result', output.snippets.length),
  onTypeDefinitionInput: (input) => log('goto_type_definition', input),
  onTypeDefinitionOutput: (output) => log('goto_type_definition result', output.snippets.length),
})

MCP Resources

The SDK automatically registers resources based on which providers you install:

diagnostics://{path}

Get diagnostics (errors, warnings) for a specific file.

Resource URI Pattern: diagnostics://{+path}

Example: diagnostics://src/main.ts

Returns diagnostics formatted as markdown with location, severity, and message information.

`diagnostics