Ged Invest MCP

An MCP (Model Context Protocol) server hosting a growing set of construction tools for Ged Invest. The first tool domain is wall formwork quantity takeoff; more tool domains can be added later as separate submodules.

Idea / architecture

Separation of concerns:

Photo / drawing / PDF
        │
        ▼
[ LLM (ChatGPT / Claude) ]     ← reads the geometry, builds structured data
        │   { segments:[{length, height, corner}], system:"BAUTEKK" }
        ▼
[ Ged Invest MCP (Python) ]    ← deterministic calculators (tools)
        │   panel selection + corners + hardware + aggregation
        ▼
[ Result: BOM ]   → panels, corners, ties, props, m², timber

• The LLM is the "eyes": it reads an image and turns it into numbers.
• The MCP is the "calculator": repeatable, no guessing. The same geometry always yields the same result - unlike LLM arithmetic.

Tool domains

Domain	Status	Tools
formwork	ready	list_formwork_systems, formwork_catalog, count_formwork, concrete_pressure_check
(future)	planned	additional construction tools register the same way

Formwork systems

System	Max pressure	Catalog
BAUTEKK	40 kN/m²	verified against DTR BauTekk 04/2022 + project PDF (R01)
BAUFRAME	60 kN/m²	default values — to be verified
BAUSCHAL	80 kN/m²	default values — to be verified

BAUTEKK data taken from the manufacturer DTR: panel widths (10/20/25/30/45/50/60/75/90 cm, 70 cm as VT), three heights (90/120/150 cm), real article numbers for every size, outer/inner corners per height, and the connector rule (5/4/3 connectors per joint for 150/120/90 cm plates). Tie and prop counts remain design-dependent estimates.

BAUFRAME/BAUSCHAL catalogs contain sensible starting values. Confirm panel sizes and article numbers against the official BAUKRANE catalog before production use (src/ged_invest_mcp/formwork/catalog.py).

Install

Requires Python ≥ 3.10.

python3.13 -m venv .venv
source .venv/bin/activate
pip install -e .

Run

The server supports two transports from a single entry point.

stdio (local — Claude Desktop / Cursor)

python -m ged_invest_mcp.server        # stdio by default
ged-invest-mcp

In this mode you host no network server — the client (Claude/Cursor) launches the Python process itself and talks to it over stdin/stdout. When the client closes, the process ends. No ports, no hosting.

HTTP (remote — ChatGPT / connectors)

python -m ged_invest_mcp.server --http                 # http://0.0.0.0:8000/mcp
python -m ged_invest_mcp.server --http --port 9000
python -m ged_invest_mcp.server --transport sse        # legacy SSE transport

ChatGPT cannot launch a local process, so it needs an MCP exposed over HTTP at a URL. Expose a local server via a tunnel (e.g. ngrok http 8000) or deploy it, then add https://.../mcp as a custom connector.

count_formwork — two ways to pass geometry

A) Segment list (you know wall lengths and corners):

{
  "system": "BAUTEKK",
  "segments": [
    {"length": 465, "height": 150, "corner_at_end": "outer", "label": "A"},
    {"length": 465, "height": 150, "corner_at_end": "outer", "label": "B"}
  ]
}

B) Polygon (outline coordinates — corners detected automatically):

{
  "system": "BAUTEKK",
  "polygon": [[0,0],[840,0],[840,700],[0,700]],
  "height": 150
}

Client configuration

Claude Desktop / Cursor (mcp.json)

{
  "mcpServers": {
    "ged-invest": {
      "command": "/ABSOLUTE/PATH/bud-ged-mcp/.venv/bin/python",
      "args": ["-m", "ged_invest_mcp.server"]
    }
  }
}

Method (formwork, in short)

1. Wall outline → segments between corners (outer / inner / none for collinear).
2. Segment length → panel width selection (dynamic programming, min. timber).
3. Height → panels are stacked to reach the wall height; the top course may stand above the pour line (reported as top_overshoot_cm, panels are not cut).
4. Panels = columns × courses × faces (default 2 = wall centerlines; pass faces=1 if the input already lists both faces separately).
5. Corners: one corner element per course.
6. Hardware: full family from the catalog (ties, nuts, cones, plugs, spacer tubes, connectors, pins, wedges, corner tensioners, props with heads/feet). Coefficients are approximate and should be calibrated against the DTR.
7. Horizontal leftover that does not fit panels → timber infill [lm].

Auditable output

count_formwork returns, besides the BOM:

• input_echo — the geometry actually used (polygon-derived side lengths, corner types and winding), so you can verify the LLM read the drawing correctly;
• assumptions — faces, corner rule, spacings, panel heights, policies;
• per-segment panels_horizontal_per_face / courses_vertical_per_face layout;
• reconciliation — geometry area vs panel area and waste %;
• units, catalog_version, warnings, disclaimer.

This is an engineering estimator — the result supports quoting/ordering and must be approved by the site manager (per the project notes).

concrete_pressure_check — fresh concrete pressure (DIN 18218)

Computes the maximum characteristic lateral fresh concrete pressure per DIN 18218:2010-01 from the pouring (rise) rate v, consistency class (F1–F6, SCC) and setting time tE, caps it by the hydrostatic pressure γc·H, and compares it to the formwork system's limit:

• characteristic_pressure_kn_m2, hydrostatic_pressure_kn_m2, design_pressure_kn_m2, governing;
• within_limit and max_pouring_rate_for_limit_m_per_h (the fastest safe rate);
• pass system (e.g. BAUTEKK) to auto-fill the limit (40 kN/m²) and the DTR process cap (2 m/h).

Simplified 15 °C reference model (no temperature/admixture corrections). The real pressure and safe pouring rate remain the site manager's responsibility.

Adding a new tool domain

1. Create src/ged_invest_mcp/<domain>/ with a register(mcp) function.
2. Import and call it in server.py.

Tests

python -m pytest -q