API & MCP
Everything a person can do on Section Properties Calculator: Area, Moments of Inertia, Torsion Constant, a program or AI agent can do with the same inputs and get the identical result.
HTTP API
POST https://prooflinesectionproperties.usefulweb.app/api/v1/calculate– run Section Properties Calculator: Area, Moments of Inertia, Torsion ConstantGET https://prooflinesectionproperties.usefulweb.app/api/v1/tool– inputs, output schema, examples- OpenAPI 3.1: /openapi.json · /openapi.yaml
- Errors:
application/problem+json;422includes per-fielderrors.
Section Properties Calculator: Area, Moments of Inertia, Torsion Constant
Enter the shape and dimensions of a beam cross-section — solid rectangle, solid circle, circular tube, rectangular hollow section or doubly symmetric I-section — and get the area, the second moments of area about both axes, the St. Venant torsion constant, the elastic section moduli, the torsion modulus, the radii of gyration and, with a typical steel, stainless, aluminium or timber material, the mass per metre and the bending and torsional stiffness. A drawing shows the section with its local axes, and a ready line feeds the 3-D frame model of Proofline’s truss and frame solver. Part of the Proofline math notebook.
| Field | Type | Default | Description |
|---|---|---|---|
shape | select (rect, circle, tube, rhs, i) | "rect" | Shape |
b | number | — | Width b. Rectangle, hollow section and I-section: the width along the local y axis (flange width of an I-section). |
h | number | — | Depth h. Rectangle, hollow section and I-section: the depth along the local z axis. |
d | number | — | Diameter d. Circle and tube: the outside diameter. |
t | number | — | Wall thickness t. Tube and hollow section. |
tf | number | — | Flange thickness tf. I-section. |
tw | number | — | Web thickness tw. I-section. |
material | select (steel, s355, stainless, aluminium, timber, none) | "steel" | Material. Typical values for the mass per metre and the stiffnesses EI and GJ. |
name | text | "S1" | Section name for the frame model |
Example request
I-section like an IPE 200 (100 × 200, tf 8.5, tw 5.6)
curl -X POST https://prooflinesectionproperties.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"shape":"i","b":100,"h":200,"tf":8.5,"tw":5.6,"material":"steel","name":"IPE200"}'Every result contains
inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.
MCP (Model Context Protocol)
- Streamable HTTP endpoint:
https://prooflinesectionproperties.usefulweb.app/mcp– protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake). - Tools:
proofline_section_properties - Local stdio connector:
node src/mcp-stdio.ts --tool=proofline-section-properties
{
"mcpServers": {
"proofline-section-properties": { "type": "http", "url": "https://prooflinesectionproperties.usefulweb.app/mcp" }
}
}