This server does not currently have a deployable release on Glama. Follow the repository's setup instructions to install and configure it for your MCP client, including any required credentials and local dependencies.
An MCP server with six deterministic calculators for people who run desktop FDM (material-extrusion) 3D printers. Four tools come from my 24-679 Homework 4 agent; two are new in Homework 5 and were chosen from user interviews (see the HW5 report).
Tool | Origin | What it answers |
| HW4 | How much filament, time, energy and money will this print take? |
| HW4 | Will a printed bracket, hook or clip hold its load? |
| HW4 | Can a printed cup hold a liquid (pressure, seal, heat)? |
| HW4 | What do failures waste per good part, unmonitored vs detect-and-stop vs detect-and-adapt? |
| new | If I start this job before bed, how long can a failure go unseen, what will it waste, and is there a better start time? |
| new | A part came out (or was repaired) off-design: KEEP, TEST_BEFORE_USE or REPRINT? |
The server only computes. It never talks to a printer, never edits G-code and never calls an LLM.
Requires Python 3.10+ and the MCP Python SDK 2.x.
git clone <this repo> && cd fdm-mcp-server
python3 -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
pytest -q # 20 tests, all through an MCP clientMCP Inspector (Node 22+):
npx @modelcontextprotocol/inspector .venv/bin/fdm-mcpOpen the URL it prints (it includes the session token), switch the server on, then go to Tools.
Claude Desktop / Claude Code: add to the client's MCP config:
{ "mcpServers": { "fdm-print-tools": { "command": "/ABSOLUTE/PATH/fdm-mcp-server/.venv/bin/fdm-mcp" } } }or claude mcp add fdm-print-tools -- /ABSOLUTE/PATH/fdm-mcp-server/.venv/bin/fdm-mcp.
Streamable HTTP instead of stdio: fdm-mcp --http (serves http://127.0.0.1:8000/mcp).
Recorded demo: python demo/client_demo.py launches the server over stdio, makes the five calls in the report
and writes demo/transcript.json / .md. Inspector screenshots are in demo/screenshots/.
Related MCP server: fabtally-mcp
Every tool returns the same structured record (outputSchema = ToolRecord):
tool, verdict (OK | CAUTION | FAIL), decision (new tools), summary,
results {key: {label, value, unit}}, checks [{name, status, detail}], features (check_deviated_part),
inputs (everything used, after defaults), defaults_used, assumptions, warnings, human_checksErrors. Invalid input never crashes the server; the call returns isError: true with a readable message.
There are two layers. (1) The schema carries types, enums, HH:MM patterns and min/max for every number, so
the SDK rejects out-of-range or wrongly typed arguments before the tool runs (pydantic message naming the field).
(2) The tool enforces rules that a schema cannot express and answers Invalid input: …, for example a layer
height above 80 % of the line width, a missing load, away_from == back_at, or a fit feature without a tolerance.
All tools are annotated readOnlyHint: true, idempotentHint: true, openWorldHint: false.
Tool | Required inputs (unit, range) | Main optional inputs (default) | Key results |
|
| material PLA/PETG/ABS, infill 0–100 % (15), walls 1–10 (2), line width 0.2–1.2 mm (0.42), layer 0.04–0.6 mm (0.2), speed 5–600 mm/s (150), flow limit 1–60 mm³/s (21), η 0.1–1 (0.6), power 10–2000 W (110) | filament g and m, print time h, energy kWh, cost $ |
|
| orientation flat/upright, target SF 1–10 (2), interlayer factor 0.1–1 (0.5) | stress MPa, safety factor, breaking load N, deflection mm, thickness for target |
|
| liquid −20–100 °C (20), density 500–2000 kg/m³ (1000) | capacity mL, hoop stress MPa, wall lines, heat margin °C |
|
| p fail 0–0.9 (0.15), failure point 0–1 (0.3), detection delay 0–600 min (10), recoverable share 0–1 (0.4) | wasted g, h, $ per good part for A/B/C and savings |
plan_unattended_print (new)Purpose. Interviewees leave long prints running overnight or in an empty lab and find failures hours later. This tool shows how exposed a particular start time is and searches a window for a better one.
Input | Type / unit | Range | Default |
| float, h / g | 0.05–200 / 0.1–10 000 | required |
|
| 00:00–23:59; away window may cross midnight, must not be empty | required |
|
| none | |
| float | 0–0.9 | 0.15 (assumption) |
| float, – / h | 0–1 / 0.05–5 | 0.5, 0.5 h (assumption) |
| float, – / min | 0–1 / 0–600 | 0.6, 10 (auto_stop only) |
| float, min | 1–480 | 60 |
|
| both or neither | none (no search) |
Method. Failure time is drawn from a mixture: early_failure_share in the first early_window_h, the rest uniform
over the job (2 000-point quadrature). A failure is noticed at the next look while someone is present (half the
check interval on average), at back_at while nobody is, or detection_delay_min later for the detection_coverage
share caught by auto-stop. A failed job keeps extruding until stopped or the G-code ends.
Results. finish time, unattended share and hours, chance a failure happens unattended, mean and worst-case hours
until known, idle hours before restart, expected wasted g / h / $ for this attempt, and with a search window the
recommended start, its finish time and its expected waste. Checks: first layers watched, unseen failure time (> 2 h),
no automatic stop. Errors: bad clock strings (schema), away_from == back_at, only one search bound (tool).
check_deviated_part (new)Purpose. Interviewees said that whether an off-design part still works is "very part specific", that only the designer knows which features can take error, and that a repaired part that looks fine may not be strong enough.
Input | Type / unit | Range | Default |
| 1–30 × { | mm 0.1–500, tolerance 0.01–10 | tolerance required for fit and load_bearing; 1.0 mm for cosmetic |
| {material, length_mm, width_mm, nominal_thickness_mm, measured_thickness_mm, load_N or load_kg, orientation, target_safety_factor} | as | optional |
| bool | false | |
| float, h / g | 0.05–500 / 0.1–10 000 | optional, shows what scrapping costs |
Method. Each feature passes if |measured − nominal| ≤ tolerance. Out-of-tolerance cosmetic features give CAUTION;
fit or load-bearing ones give FAIL. If beam is given, check_cantilever runs at the design and as-printed
thickness (strength ∝ t²). Decision: REPRINT if any functional feature fails or the arm's safety factor drops below
1; TEST_BEFORE_USE if a load-bearing feature has no strength check, its safety factor is below target, or the repair
crossed the load path; otherwise KEEP. Errors: a fit/load-bearing feature without tolerance_mm, bad role,
out-of-range numbers.
Client (LLM host, Inspector, a person) | Server (this repo) |
Understand the request, choose the tool, ask the user for missing measurements | Validate every input against its schema and domain rules |
Never compute numbers itself; quote results with units | Compute deterministically; same input → same output |
Show | Report every default, assumption and warning it applied |
Decide what to do (print, keep, reprint), with the user | Recommend only; it has no access to printers or files |
Hold API keys and conversation state | Holds no state, secrets or network access |
MIT. Material values come from Bambu Lab PLA/PETG Basic TDS v2.0 and the Stratasys ABS-M30 data sheet.
This server cannot be deployed
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