feat(core): add @modelcontextprotocol/inspector-core package

[olaservo]

Summary

Reference implementation of @modelcontextprotocol/inspector-core - a reusable core package for MCP client logic with no React dependencies.

Specification References

This implementation follows the V2 specification documents in specification/:

Spec	Implementation
v2_scope.md	Package architecture enabling CLI/TUI/Web sharing
v2_ux_handlers.md	Handler interfaces for sampling, elicitation
v2_tech_stack.md	TypeScript, MCP SDK integration

Related: Issue #983 (data spec discussion)

Directory Structure

core/
├── src/
│   ├── client.ts         # MCP client lifecycle (create, connect, disconnect)
│   ├── transport.ts      # StreamableHTTPClientTransport factory
│   ├── handlers.ts       # Sampling/elicitation handler creation
│   ├── index.ts          # Public API exports
│   ├── data/
│   │   ├── repositories.ts  # CRUD interfaces (ServerConfig, History, Logs, TestingProfile)
│   │   ├── services.ts      # Stateful interfaces (Connection, Execution)
│   │   ├── memory.ts        # In-memory stub implementations
│   │   └── index.ts
│   └── types/
│       ├── auth.ts          # OAuth state types
│       ├── capabilities.ts  # Server capabilities
│       ├── clientRequests.ts # Sampling/elicitation request types
│       ├── history.ts       # History entries with parent-child relationships
│       ├── logs.ts          # RFC 5424 log levels
│       ├── responses.ts     # MCP response types
│       ├── servers.ts       # Server config types
│       ├── tasks.ts         # Task management types
│       ├── testingProfiles.ts # Auto-respond configuration
│       └── index.ts
├── test-core.js          # Unit tests for memory implementations
└── test-real-server.js   # Integration tests with Everything MCP server

Core Features

• MCP client lifecycle: createMcpClient, connectClient, disconnectClient, isClientConnected
• Transport factory: createHttpTransport for Streamable HTTP connections
• Handler creation: createSamplingHandler, createElicitationHandler with queue-based patterns
• Repository interfaces: ServerConfigRepository, HistoryRepository, LogsRepository, TestingProfileRepository
• Service interfaces: ConnectionService, ExecutionService for stateful operations
• Memory implementations: In-memory stubs for all repositories/services (testing, CLI, TUI)
• Type definitions: History entries with parent-child relationships, RFC 5424 log levels, testing profiles

Design Principles

1. No React dependencies - Can be used in CLI, TUI, or test frameworks
2. Interface-first data layer - Repository/service interfaces with swappable implementations
3. Stubbable for testing - Memory implementations enable unit tests without I/O

Test Plan

• Unit tests pass: node core/test-core.js (all 21 tests)
• Integration tests pass with Everything server running
• Review feedback incorporated

Stack

• Followed by: feat(client): add Mantine UI with MCP SDK integration #1022 (Mantine UI)

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