@hitl-kit/mcp

MCP server for HITL Kit. Exposes the 15 HITL primitive event kinds as Model Context Protocol tools so Claude Code, Cursor, Claude Desktop, and any MCP-aware client can emit schema-validated human-in-the-loop events.

Why this exists

The MCP (Model Context Protocol) standardises how agent clients talk to tools. If you add HITL Kit as an MCP server, an agent running in any MCP-aware client — Claude Code, Claude Desktop, Cursor, future ones — can call hitl_interrupt_card, hitl_qa_flow, etc. The server validates input against the @hitl-kit/core Zod schemas and returns a structured HITL event as the tool result. Zero per-client wiring.

Install

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "hitl-kit": {
      "command": "npx",
      "args": ["-y", "@hitl-kit/mcp"]
    }
  }
}

Restart Claude Desktop. In the chat you should see hitl_* tools available.

Cursor

In Cursor Settings → MCP Servers → Add:

{
  "mcpServers": {
    "hitl-kit": {
      "command": "npx",
      "args": ["-y", "@hitl-kit/mcp"]
    }
  }
}

Claude Code

claude mcp add hitl-kit npx -y @hitl-kit/mcp

Or add manually to your Claude Code settings (~/.claude/mcp-servers.json or per-project .claude/mcp-servers.json):

{
  "mcpServers": {
    "hitl-kit": {
      "command": "npx",
      "args": ["-y", "@hitl-kit/mcp"]
    }
  }
}

Tools exposed

| Tool name | Event kind | |---|---| | hitl_interrupt_card | hitl.card | | hitl_subagent_status | subagent.status | | hitl_mini_trace | trace.mini | | hitl_ai_generation_scale | scale.ai_generation | | hitl_context_chips | chips.context | | hitl_qa_flow | qa.flow | | hitl_writing_agent | agent.writing | | hitl_research_agent | agent.research | | hitl_batch_queue | batch.queue | | hitl_search_result | result.search | | hitl_approve_reject | approval.binary | | hitl_diff_result (v0.6a) | result.diff | | hitl_citation_result (v0.6a) | result.citation | | hitl_editable_plan (v0.6a) | plan.editable | | hitl_tool_call (v0.6a) | tool.call |

Each tool's input JSON Schema is generated from the matching Zod schema in @hitl-kit/core (minus the kind discriminator, which the server adds). The tool result is a JSON-stringified HitlEvent ready to pass to <HitlEventRenderer />.

Programmatic usage (advanced)

If you want to embed the HITL Kit MCP server in a custom host:

import { createHitlKitServer } from "@hitl-kit/mcp";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";

const server = createHitlKitServer();
const transport = new StdioServerTransport();
await server.connect(transport);

Or use a non-stdio transport (e.g., Streamable HTTP) — the server returned by createHitlKitServer() is a standard MCP Server object.

Dev / local test

pnpm --filter @hitl-kit/mcp build
# Then link and configure Claude Desktop to point at the built binary.
# See local dev notes in the repo's CONTRIBUTING.md.

Send a list-tools request via MCP Inspector or any stdio client; you should get all 15 hitl_* tools. Calling one with valid input returns a HitlEvent; calling with invalid input returns a structured Zod error.

Part of HITL Kit

• Schemas → @hitl-kit/core
• Renderer → @hitl-kit/react
• LangGraph adapter → @hitl-kit/langgraph
• Vercel AI SDK adapter → @hitl-kit/ai-sdk
• Paper → hitlkit.dev/paper

License

MIT License

Copyright (c) 2023-2026 Ubik, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.