Steel Brain

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.

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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:

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)

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

{
  "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.

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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 :

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: [email protected]

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:

make test

or directly:

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.

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

License

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