MCP server

@ntcore-ts/mcp is a Model Context Protocol server for live NetworkTables. MCP hosts such as Cursor and Claude Desktop can connect, inventory topics, read values (including decoded structs), sample updates, and publish when the write gate is open.

It is built on @ntcore-ts/client. It is not a Driver Station and does not replace offline WPILOG tools.

Install

npm install -g @ntcore-ts/mcp
# or run without a global install:
npx ntcore-ts-mcp

Cursor / Claude Desktop

Add a stdio server to your MCP config:

{
  "mcpServers": {
    "ntcore-ts": {
      "command": "npx",
      "args": ["-y", "ntcore-ts-mcp"],
      "env": {
        "NT_ALLOW_WRITES": "0",
        "NT_REQUIRE_LOCALHOST": "1"
      }
    }
  }
}

From this monorepo (development):

{
  "mcpServers": {
    "ntcore-ts": {
      "command": "npx",
      "args": ["tsx", "packages/mcp/src/cli.ts"],
      "cwd": "/path/to/ntcore-ts",
      "env": {
        "NT_ALLOW_WRITES": "0",
        "NT_REQUIRE_LOCALHOST": "1"
      }
    }
  }
}

Reload the MCP server in the host after changing the config. Point it at a running NT server (for example npm run serve -w @ntcore-ts/example-robot on port 5810).

Agent workflow

1. Call nt_guide first if you need the tool map and write-gate status.
2. nt_connect with host / port (or the team / URI options the tool accepts).
3. nt_list_topics with a prefix such as /MyTable/.
4. Use nt_get / nt_get_multiple for scalars, arrays, and JSON.
5. Use nt_get_decoded for struct:… / protobuf topics (returns JSON).
6. Use nt_subscribe for a short timed sample window (summary or samples).
7. Enable writes only when needed (see below), then nt_set / nt_set_multiple.
8. nt_disconnect when finished.

Tools

Tool	Role
nt_guide	Workflow, tool choice, write-gate status
nt_connect / nt_disconnect / nt_connection_info	Session
nt_list_topics	Inventory (prefix filter)
nt_get / nt_get_multiple	Scalars / arrays / JSON
nt_get_decoded	Struct / protobuf → JSON
nt_subscribe	Timed sample window
nt_list_struct_types	Built-in + discovered struct names
nt_set_write_mode	Enable/disable writes (confirm: true to enable)
nt_set / nt_set_multiple	Gated publish

Writes (safety)

Writes are off by default.

• Enable for the session: nt_set_write_mode({ enabled: true, confirm: true })
• Or start the process with NT_ALLOW_WRITES=1
• Path allowlist (default): /SmartDashboard/**,/Tuning/**,/MyTable/** via NT_WRITE_ALLOWLIST
• Optional: NT_REQUIRE_LOCALHOST=1 refuses writes when the NT host is not local

NetworkTables cannot enable or disable the robot (FMS/Driver Station does that). Do not let an agent command a live robot — published values can still move mechanisms if robot code is listening.

Programmatic use

You can drive the same service from Node without an MCP host:

import { createNtMcpServer, NtMcpService } from '@ntcore-ts/mcp';

const service = new NtMcpService();
await service.connect({ host: 'localhost', port: 5810 });
const list = service.listTopics('/MyTable/');

const server = createNtMcpServer({ service });

Implementation notes

• Topic discovery uses short-lived prefix snapshots. A long-lived prefix=/ subscription on the same client instance can block later typed topic subscriptions; the MCP layer snapshot-then-unsubscribes and decodes struct bytes from inventory for nt_get_decoded.
• The MCP process sets the client log level to silent so library logs never hit stdout (stdout is the JSON-RPC channel). Package messages go to stderr as single lines.

See also

• Getting started — connect with @ntcore-ts/client
• Struct / Protobuf — binary topic types agents decode via nt_get_decoded
• Package README in the repo: packages/mcp/README.md