# Modbus TCP/RTU Device (pypi · labmcp-modbus)

MCP server for Modbus TCP/RTU devices with typed, scaled register maps and per-point limits.

- Trust score: 69/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-30

## Components

- pypi · `labmcp-modbus`: 69/100 (this document), [markdown](https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus.md), [page](https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus)

## Channel facts

- Registry: `pypi`
- Package: `labmcp-modbus`
- Version: `0.1.3`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-30.

- **Supply Chain Security**: 49/100
  - Malware scan not yet available for this package.
  - No known CVEs affecting this package version or its production dependencies.
  - Runs hatchling.build at install time, a recognised build step with no custom scripting around it.
  - 2 of 19 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 100/100
  - Source repository is publicly reachable at the declared URL.
  - Cryptographically verified build provenance (signed, bound to K-Dense-AI/lab-instrument-mcps).
  - Clear OSI-approved license (Apache-2.0).
  - Actively maintained (last published 3 days ago).
  - Publishes a security disclosure policy (SECURITY.md).
- **Schema Quality & AI Usability**: 80/100
  - AI-judged instruction clarity (excellent).
  - Tool/resource definitions use about 1277 tokens (~106/item across 12 items; 12 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 13/100
  - Stability observed for 4 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 99/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 95% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 12 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 13 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the Modbus TCP/RTU Device MCP server?

Modbus TCP/RTU Device runs locally as a PyPI package, launched with uvx labmcp-modbus. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add k-dense-ai-labmcp-modbus -- uvx labmcp-modbus
```

### Cursor

```json
{
  "mcpServers": {
    "k-dense-ai-labmcp-modbus": {
      "command": "uvx",
      "args": [
        "labmcp-modbus"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "k-dense-ai-labmcp-modbus": {
      "command": "uvx",
      "args": [
        "labmcp-modbus"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add k-dense-ai-labmcp-modbus -- uvx labmcp-modbus
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "k-dense-ai-labmcp-modbus": {
      "type": "local",
      "command": [
        "uvx",
        "labmcp-modbus"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add k-dense-ai-labmcp-modbus --command uvx --arg labmcp-modbus
```

### Hermes

```yaml
mcp_servers:
  k-dense-ai-labmcp-modbus:
    command: "uvx"
    args: ["labmcp-modbus"]
```

### Netclaw

```json
{
  "McpServers": {
    "k-dense-ai-labmcp-modbus": {
      "Transport": "stdio",
      "Command": "uvx",
      "Arguments": [
        "labmcp-modbus"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add k-dense-ai-labmcp-modbus -t stdio -c uvx -a labmcp-modbus
```

### Other

```json
{
  "mcpServers": {
    "k-dense-ai-labmcp-modbus": {
      "command": "uvx",
      "args": [
        "labmcp-modbus"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-30 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-28 (score 68, +29)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-27 (score 39, −33)

- [security regression] Tool safety: pass → unverified
- [security] Stability: Stability not yet verified: we do not have a sandbox capture of the MCP schema this version of the package serves yet.
- [functional regression] Capabilities: pass → unverified
- [functional regression] Tool coverage: 100 → unverified
- [functional] First check of Schema quality: unverified
- [functional] Package version: 0.1.2 → 0.1.3

### 2026-09-26 (score 72)

First indexed and scored.

## MCP tools (12)

### `get_connection_info` (~40 tokens)

Get Connection Info

Report which instrument is connected (identity, address, simulated or real),
whether the server is read-only, and the active safety limits. Call this first.

### `get_command_log` (~46 tokens)

Get Command Log

Return the most recent raw commands sent to / replies received from the
instrument (newest last). Useful for debugging and for recording what was done.

Input parameters:

- `limit` (integer)

Output parameters:

- `result` (array)

### `reconnect` (~35 tokens)

Reconnect

Close and re-open the connection to the instrument (e.g. after it was power
cycled or a cable was re-plugged).

### `list_points` (~52 tokens)

List Points

Describe the loaded register map: device, every named point (table, 0-based address,
type, scaling, unit, writable, min/max, enum) and the safe-state steps. Works without a
connection.

Output parameters:

- `device` (object)
- `error`
- `loaded` (boolean)
- `points` (array)
- `raw_writes` (boolean)
- `safe_state` (array)
- `source`
- `unit_id`

### `read_points` (~69 tokens)

Read Points

Read named points from the register map, decoded and scaled into engineering units
(e.g. process_temperature = 25.1 °C). A point that cannot be read gets an `error`
instead of failing the whole call.

Input parameters:

- `names`: Point names from list_points; omit for all points

Output parameters:

- `result` (array)

### `read_registers` (~140 tokens)

Read Registers

Read raw holding or input registers (unsigned 16-bit), optionally decoded as int16,
32-bit or 64-bit values. For exploring a device; prefer read_points when a register map
describes it.

Input parameters:

- `address` (integer, required): 0-based start address
- `byte_order` (string): big = standard Modbus byte order
- `count` (integer): Number of registers
- `decode_as` (string): Also decode the registers as this type
- `table` (string): holding (FC03) or input (FC04)
- `word_order` (string): 32/64-bit: big = high word first

Output parameters:

- `address` (integer)
- `count` (integer)
- `decoded`: Values decoded with decode_as ("nan"/"inf"/"-inf" for non-finite floats)
- `hex` (array)
- `registers` (array): Raw unsigned 16-bit values
- `table` (string)
- `timestamp` (string)

### `read_coils` (~49 tokens)

Read Coils

Read coils (FC01): single-bit outputs such as run/stop or relay states.

Input parameters:

- `address` (integer, required): 0-based start address
- `count` (integer): Number of coils

Output parameters:

- `address` (integer)
- `count` (integer)
- `table` (string)
- `timestamp` (string)
- `values` (array)

### `read_discrete_inputs` (~52 tokens)

Read Discrete Inputs

Read discrete inputs (FC02): single-bit, read-only status such as alarms or limit switches.

Input parameters:

- `address` (integer, required): 0-based start address
- `count` (integer): Number of inputs

Output parameters:

- `address` (integer)
- `count` (integer)
- `table` (string)
- `timestamp` (string)
- `values` (array)

### `write_point` (~125 tokens)

Write Point

Write a named point from the register map (setpoint, mode, output enable...). The value
is checked against the point's writable flag, min/max or enum BEFORE sending, converted
to raw registers, written, then read back. Changing setpoints and outputs acts on real
equipment. If the write succeeds but the read-back fails, `read_back_error` says why.

Input parameters:

- `name` (string, required): A writable point from list_points
- `value` (required): Engineering value (e.g. 37.5 for °C), true/false, or an enum label

Output parameters:

- `matches` (boolean): True if the read-back equals the written value
- `name` (string)
- `read_back`
- `read_back_error`: Why the value could not be read back (it WAS written)
- `requested`
- `timestamp` (string)
- `unit` (string)
- `written`: Value after rounding to the register's resolution

### `write_register` (~88 tokens)

Write Register

Write one raw holding register (FC06). No scaling or limits are applied, so only use it
for addresses the register map does not describe (mapped addresses are refused: use
write_point). Returns a read-back if the register is readable.

Input parameters:

- `address` (integer, required): 0-based holding-register address
- `value` (integer, required): Raw value (negative = int16 two's complement)

### `write_registers` (~70 tokens)

Write Registers

Write consecutive raw holding registers (FC16), e.g. both halves of a 32-bit value.
No scaling or limits are applied; mapped addresses are refused (use write_point).

Input parameters:

- `address` (integer, required): 0-based start address
- `values` (array, required): Raw 16-bit values

### `write_coil` (~74 tokens)

Write Coil

Switch one raw coil (FC05). Coils often start or stop equipment (heaters, pumps,
motors); mapped coils are refused here (use write_point).

Input parameters:

- `address` (integer, required): 0-based coil address
- `value` (boolean, required): true = ON (0xFF00), false = OFF

## Diagnostics

Captured diagnostic sections: Provenance, Install scripts, Dependencies. The full working is on the page: https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus#diagnostics

## Score history

- 2026-09-30: 69
- 2026-09-29: 68
- 2026-09-28: 68
- 2026-09-27: 39
- 2026-09-26: 72

## Common questions

### What is the Modbus TCP/RTU Device MCP server?

Modbus TCP/RTU Device is an MCP server listed in the public MCP registry as io.github.K-Dense-AI/labmcp-modbus. MCP server for Modbus TCP/RTU devices with typed, scaled register maps and per-point limits. This page covers its PyPI package (labmcp-modbus).

### Is the Modbus TCP/RTU Device MCP server safe to use?

Modbus TCP/RTU Device scores 69 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 30 September 2026. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the Modbus TCP/RTU Device MCP server expose?

Modbus TCP/RTU Device exposes 12 tools: get_connection_info, get_command_log, reconnect, list_points, read_points, and 7 more. Their descriptions and schemas cost roughly 840 tokens of context every time the server is loaded.

### Is the Modbus TCP/RTU Device MCP server still maintained?

Modbus TCP/RTU Device is still listed as active in the MCP registry. We last reached this channel on 30 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the Modbus TCP/RTU Device MCP server under?

Modbus TCP/RTU Device declares the Apache-2.0 licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- PyPI project: https://pypi.org/project/labmcp-modbus/
- Socket report: https://socket.dev/pypi/package/labmcp-modbus
- Repository: https://github.com/K-Dense-AI/lab-instrument-mcps
- Website: https://github.com/K-Dense-AI/lab-instrument-mcps/tree/main/servers/protocols/modbus
- Changelog RSS feed: https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus.xml
- Changelog JSON feed: https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus.json
- HTML version of this page: https://verifymcp.io/servers/k-dense-ai-labmcp-modbus/labmcp-modbus