Steel Brain

An MCP server providing steel domain knowledge to AI agents — grade properties, substitution verdicts, and mill-cert guidance, delivered as MCP tools your agent can call.

Also available as a REST API at https://api.steelbrain.dev.

MCP server

Steel Brain is a Model Context Protocol server. It exposes three MCP tools, over remote streamable HTTP (no install) or local stdio:

MCP Tool	What it does
`grade_lookup`	Properties, chemistry, forms, applications, weldability for a steel grade. Aliases resolved (4140 = 42CrMo4 = SCM440; S355 = ST52).
`substitution_check`	Given from_grade, to_grade, application, returns a verdict (valid / conditional / invalid) with reasoning on whether one grade can substitute another.
`cert_guide`	Which mill certificate applies for a grade + use case (EN 10204 3.1/3.2, class certs ABS/DNV/LR/BV/NK) and what to check.

Remote (no install, free)

Point any MCP client that supports streamable HTTP at:

Code

https://api.steelbrain.dev/mcp

{
  "mcpServers": {
    "steel-brain": { "type": "http", "url": "https://api.steelbrain.dev/mcp" }
  }
}

Claude Code: claude mcp add --transport http steel-brain https://api.steelbrain.dev/mcp

No API key needed. There is a shared daily cap to keep the server healthy.

Local (stdio)

Terminal

pip install -r requirements.txt
python -m steel_brain.mcp_server

Starts the MCP server on stdio transport, ready for any MCP client (Claude Desktop, Claude Code, or any MCP-compatible agent).

Example MCP client config

JSON Config

{
  "mcpServers": {
    "steel-brain": {
      "command": "python",
      "args": ["-m", "steel_brain.mcp_server"]
    }
  }
}

Built with the official MCP SDK (mcp package), registering three tools via the standard MCP tool interface.

Why Steel Brain

LLMs guess at steel. They will tell you 4140 annealed can stand in for 4140 pre-hardened, and scrap the job. Steel Brain answers from a human-verified knowledge base built by a working steel trader, and returns an honest "not in knowledge base" rather than a confident guess.

The valuable part is the substitution and cert logic:

4140RB to 4140QT (annealed vs pre-hardened): invalid, same alloy, opposite heat-treat
316L to 304L for marine: invalid, different corrosion class
EH36 to S355 structural: valid one way, conditional the other
Seamless vs ERW for pressure service: never interchangeable

Coverage

23 grades across carbon, alloy, stainless. Round bar, hollow bar, plate, pipe. 39 substitution rules, 4 cert guides.

REST API (alternative to MCP)

Same knowledge over REST at https://api.steelbrain.dev :

Terminal

curl "https://api.steelbrain.dev/v1/grade/4140QT" -H "X-API-Key: YOUR_KEY"
curl "https://api.steelbrain.dev/v1/substitution?from_grade=316L&to_grade=304L&application=machined" -H "X-API-Key: YOUR_KEY"

Free tier at launch. Contact: dryow.jt@gmail.com

Honesty by design

Grade properties: published-standard ranges (ASTM/EN/JIS/API/ABS), labelled as such.
Substitution + cert logic: trade-verified, dated rulings from a working trader.
Unknown grades: honest "not in knowledge base," never fabricated.

Development

One-command local test setup:

Code

make test

or directly:

Code

bash scripts/test.sh

This creates a .venv (via python3 -m venv .venv) if it doesn't exist yet, installs requirements.txt into it, sets SB_SERVE_UNVERIFIED=1 (needed so the test suite can exercise unverified KB entries), and runs pytest. Works on macOS and Linux. Extra arguments are passed through to pytest, e.g. bash scripts/test.sh tests/test_gate2.py -v.

Code

python -m pytest tests/    # 15 tests (10 acceptance + 5 domain-safety guards)

License

Code: MIT (see LICENSE). Knowledge base (kb/): proprietary (see NOTICE).