What is i3X-MCP-Server CLAUDE.md?

A set of project instructions for Claude Code and contributors working on an MCP server for i3X-compatible manufacturing data systems. i3X is a standard for accessing data from industrial equipment and plant systems.

It is for guiding development of the i3X MCP server, including its tools, inputs, outputs, and error messages for plant engineers and operators.

It gives contributors the project background, intended users, architecture, and fixed design decisions before they change the code.

How cesmii/i3X-MCP-Server configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to cesmii/i3X-MCP-Server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/cesmii/i3X-MCP-Server/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/cesmii/i3X-MCP-Server

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

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Your own site

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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

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Per session 1,668 This file is loaded in full into every session.

When invoked 1,668 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01668	$0.01668
Opus 5.5	$0.00667	$0.00667
Sonnet 5.5	$0.00334	$0.00334
Haiku 4.5	$0.00167	$0.00167

Measured 2mo ago against content hash 587da8a4bd10, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

i3X-MCP-Server CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

Context for Claude (and humans) contributing to this codebase. Read once before making changes.

What this is

An MCP server that wraps any i3X 1.0 compliant manufacturing data source for use from Claude / other MCP clients. Published as i3x-mcp on npm; end users install via npx -y i3x-mcp@latest in their Claude Desktop config.

Audience

End users of i3X-compliant systems — plant engineers, operators, maintenance — not i3X client developers. Every design decision flows from that: tool names, descriptions, input shapes, and error messages should make sense to someone who knows their plant, not someone who's read the i3X spec.

When in doubt: would a plant engineer recognize the input/output? If a tool requires the user (or model) to know about elementId, namespaceUri, or maxDepth, push that complexity inside the tool.

Locked-in design decisions

These aren't up for casual revision — they shape the whole surface. If you want to revisit one, raise it explicitly.

Opinionated tool surface, not a thin 1:1 wrapper of i3X endpoints. ~12 tools, each composed from one or more i3X calls.
Read-only by default; update_value and write_history only register when --enable-writes is passed. Setpoint writes can affect live equipment.
Connection is runtime-configurable via the connect tool. Env vars (I3X_BASE_URL, etc.) are an optional bootstrap, not a requirement. The server always starts; data tools refuse with a friendly "call connect first" message until connected.
Catalog cached locally + fuzzy-searched with fuse.js. i3X has no pagination or full-text search; this is how we make discovery work.
Subscriptions are not exposed as a lifecycle. The single watch_values tool creates a subscription, polls /sync for a bounded duration (max from runtime.watchMaxDurationSec), and tears it down in finally. Prevents orphaned subscriptions on the i3X server.
History aggregation is server-side. get_history accepts aggregation: raw|avg|min|max|count and a bucket interval. Raw mode is capped to protect the LLM's context window.
Times accept relative strings (1h, last 30m, yesterday) and RFC 3339. Centralized in src/time.ts.
Values are enriched with units inline when the ObjectType schema declares them. Centralized in src/units.ts.

Read the full file on GitHub · 91 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 91 lines · 1,668 tokens per session scan A 587da8a4bd10

Subscribe to this mod's changes

i3X-MCP-Server CLAUDE.md is an instructions file published in the GitHub repository cesmii/i3X-MCP-Server (2 stars, last pushed 4mo ago), licensed MIT. It adds 1,668 tokens to every session, about $0.0067 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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i3X-MCP-Server: Instructions file for Claude Code