@hashi-mcp/core

Hashi runtime — Bridge, Tool, Transport, Lifecycle. The foundation every Hashi package builds on.

This package defines the four primitives every Hashi integration uses:

• Bridge — a connection to one desktop app. Holds the transport, the lifecycle hooks, and the registered tools.
• Tool — one capability exposed to Claude. Has a name, a description, optional input/output schemas, and a handler.
• Transport — the wire layer. Implementations live in dedicated packages (@hashi-mcp/transport-http, -ws, -file, ...).
• Lifecycle — optional hooks observed when the bridge connects, disconnects, or errors.

The package also exports custom error types: HashiError, TransportError, ToolError, AuthError, LifecycleError.

Install

pnpm add @hashi-mcp/core

Quick example

import { defineBridge, defineTool } from '@hashi-mcp/core'
import { httpTransport } from '@hashi-mcp/transport-http'

const bridge = defineBridge({
  app: { id: 'excel', name: 'Microsoft Excel', vendor: 'microsoft' },
  transport: httpTransport({ endpoint: 'http://127.0.0.1:7654' }),
  tools: [
    defineTool({
      name: 'workbook.list',
      description: 'List open Excel workbooks.',
      handler: () => bridge.call('workbook.list'),
    }),
  ],
})

await bridge.connect()
const workbooks = await bridge.call('workbook.list')
await bridge.disconnect()

To expose this bridge to Claude over MCP, pair it with @hashi-mcp/server.

License

MIT © Alexandre Parena