ignition-mcp

by jsgorana

Overview Schema Source Related Servers Discussions Admin

Python

Remote

tag_read

Read live values from 1 to 100 Ignition tag paths in a single request, providing a read-only bridge to industrial data.

Instructions

Read-only, bridge plane. Read live values for 1-100 tag paths.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "paths": "<paths>"
    },
    "name": "tag_read"
  }
}

Input Schema

Name	Required	Description	Default
`paths`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 5, 2026

TDQS

B3.4/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden. It discloses 'Read-only' but omits details like rate limits, authentication requirements, behavior on invalid paths, or any potential side effects. The term 'bridge plane' is ambiguous.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise at two sentences. Every word adds value, and the critical information is front-loaded: 'Read-only' and the action are prominent.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the presence of an output schema (not shown), the description does not need to detail return values. It covers the purpose, parameter scope, and readonly nature. Missing usage guidelines and behavioral depth, but overall adequate for a simple read tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so description must compensate. It adds that the tool reads 'live values' and accepts '1-100 tag paths', which partially clarifies the single 'paths' parameter. However, it does not describe the expected path format or any constraints beyond the count.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Read live values'), the resource ('tag paths'), and includes a specific range ('1-100'). It distinguishes this read-only tool from write-oriented siblings like tag_write and tag_create.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use this tool versus alternatives (e.g., tag_browse for browsing the tag tree). The mention of 'Read-only, bridge plane' implies it's for reading, but does not clarify when to choose this over other read-like tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.