Extend Engineer MCP

.github/workflows/ci.yml

@@ -39,5 +39,8 @@ jobs:
       - name: Verify the demo runs
         run: npm run demo
 
+      - name: Verify the CLI lists tools
+        run: node dist/index.js --list
+
       - name: Verify the package contents
         run: npm pack --dry-run

CHANGELOG.md

@@ -0,0 +1,33 @@
+# Changelog
+
+This project follows semantic versioning. Adding a tool or a unit is a minor release. Breaking a tool signature is a major release.
+
+## 0.3.0 - 2026-08-03
+
+Added the fatigue analysis release.
+
+- Added the `fatigue_analysis` tool.
+- The tool reports infinite-life safety factors on four criteria.
+- The criteria are modified Goodman, Soderberg, Gerber, and ASME-elliptic.
+- The tool estimates the endurance limit for steel when you do not provide one.
+- The tool reports warnings for estimated values and yield check failures.
+- Added the `@engineerkit/engineer-mcp/engine` exports for the fatigue engine.
+- The Shigley reference now covers the fatigue chapter.
+
+## 0.2.0 - 2026-08-03
+
+Added the helical spring release.
+
+- Added the `spring_design` tool.
+- The tool reports the spring rate, the shear stress, and the safety factor.
+- The tool supports four end conditions and warns on buckling and solid height.
+- Added stiffness units to the unit layer.
+
+## 0.1.0 - 2026-08-03
+
+Initial release.
+
+- Added the MCP server over standard input and output.
+- Added tools for beams, bolts, shafts, bearings, stress, sections, and materials.
+- Added the dimension-safe unit layer.
+- Added SQLite storage and provenance for every result.

README.md

@@ -23,6 +23,7 @@ The release covers these domains:
 - Shaft torsion and first critical speed.
 - Bearing rating life to ISO 281.
 - von Mises equivalent stress.
+- Fatigue safety factors for cyclic loads.
 - Cross-section properties.
 - Dimension-safe unit conversion.
 - Material property lookup.
@@ -53,6 +54,7 @@ Warnings surface when a method uses an approximation.
 | `shaft_analysis` | Torsion stress, twist, and critical speed. |
 | `bearing_life` | ISO 281 rating life in revolutions and hours. |
 | `von_mises` | Equivalent stress and yield safety factor. |
+| `fatigue_analysis` | Infinite-life fatigue factors on four criteria. |
 | `unit_convert` | Conversion between compatible units. |
 | `material_lookup` | Curated mechanical properties of materials. |
 
@@ -147,6 +149,27 @@ References:
   - Machinery's Handbook (Thirty-first edition)
 ```
 
+A call to `fatigue_analysis` for an S355 shaft under a 150 MPa mean stress and a 100 MPa amplitude:
+
+```text
+Mean stress                             150 MPa
+Stress amplitude                        100 MPa
+Stress ratio R                            0.2
+Endurance limit                         245 MPa
+Modified Goodman safety factor            1.4
+Soderberg safety factor                1.204
+Gerber safety factor                   1.748
+ASME-elliptic safety factor            1.702
+Yield safety factor                     1.42
+
+Method: Infinite-life fatigue analysis
+Formula: R = (sm - sa)/(sm + sa); Goodman: 1/n = sa/Se + sm/Sut; Soderberg: 1/n = sa/Se + sm/Sy
+References:
+  - Shigley's Mechanical Engineering Design (Tenth edition, 2015)
+```
+
+The endurance limit is an estimate unless you provide it. The tool warns when it estimates a value.
+
 A call to `unit_convert` with a torque-to-energy request fails safely:
 
 ```text
@@ -169,7 +192,7 @@ Use a unit of the same quantity.
 The test suite is deterministic and offline.
 It covers the engines, the unit layer, the database, and the tools.
 
-- 98 tests across 10 files.
+- 126 tests across 11 files.
 - All tests pass on Node 22 and Node 24.
 - The CI workflow runs typecheck, tests, build, demo, and a package check.
 
@@ -183,7 +206,9 @@ Run `npm test` to reproduce the results.
 - The bearing factors are typical values for deep-groove ball bearings.
 - The critical speed is a first-mode approximation.
 - The spring design covers static round-wire springs only.
-  It does not estimate fatigue life for cyclic loads.
+  Use `fatigue_analysis` for cyclic loads.
+- The fatigue criteria assume a constant-amplitude cycle and an infinite life.
+  The endurance limit is an estimate for steel when you do not provide one.
 - The built-in SQLite module of Node.js is still experimental.
 
 Check the cited sources for exact values.
@@ -197,10 +222,11 @@ Each release stays useful on its own.
 
 - Helical compression spring design.
   The `spring_design` tool reports the spring rate, the shear stress, and the safety factor.
+- Fatigue analysis for cyclic loads.
+  The `fatigue_analysis` tool reports infinite-life safety factors on four criteria.
 
 ### Remaining
 
-- Add fatigue analysis for cyclic loads.
 - Add press-fit and interference-fit calculators.
 - Add more unit categories, including viscosity and thermal conductivity.
 - Add HTTP transport.
@@ -218,3 +244,5 @@ Read the boundary rules in [docs/integration.md](docs/integration.md).
 ## License
 
 MIT. See [LICENSE](LICENSE).
+
+See [CHANGELOG.md](CHANGELOG.md) for the release history.

data/references.json

@@ -3,7 +3,7 @@
     "title": "Shigley's Mechanical Engineering Design",
     "source": "McGraw-Hill Education",
     "edition": "Tenth edition, 2015",
-    "section": "Chapters 3, 5, 8, 11, and 12",
+    "section": "Chapters 3, 5, 6, 8, 11, and 12",
     "note": "Standard reference for strength, fatigue, fasteners, and bearings."
   },
   "roark-2011": {

docs/integration.md

@@ -41,10 +41,10 @@ Engineer MCP grows in independent releases. Each release stays useful on its own
 ### Complete
 
 - Helical compression spring design. The `spring_design` tool computes the spring rate, the shear stress, and the safety factor.
+- Fatigue analysis for cyclic loads. The `fatigue_analysis` tool reports infinite-life safety factors on four criteria.
 
 ### Remaining
 
-- Add fatigue analysis for cyclic loads.
 - Add press-fit and interference-fit calculators.
 - Add more unit categories, including viscosity and thermal conductivity.
 - Add HTTP transport in addition to stdio.

docs/mcp-tools.md

@@ -146,6 +146,35 @@ Inputs:
 - Cartesian mode uses `sigmaX`, `sigmaY`, `sigmaZ`, `tauXY`, `tauXZ`, `tauYZ`.
 - `yieldStrength`: enables the safety factor.
 
+## fatigue_analysis
+
+Compute the infinite-life fatigue safety factors of a constant-amplitude stress cycle.
+
+The tool evaluates four failure criteria. It reports one safety factor for each criterion. They are the modified Goodman, Soderberg, Gerber, and ASME-elliptic lines.
+
+Inputs:
+
+- `meanStress`: mean stress of the cycle in pascals.
+- `amplitudeStress`: alternating stress amplitude in pascals.
+- `material`: material name from the database. It provides the ultimate and yield strengths.
+- `ultimateStrength`: tensile ultimate strength in pascals. Required when no material is set.
+- `yieldStrength`: tensile yield strength in pascals. It enables the Soderberg, ASME-elliptic, and yield factors.
+- `enduranceLimit`: fully reversed endurance limit in pascals. The default is an estimate for steel.
+- `criterion`: primary criterion for the safety factor. The options are `goodman`, `soderberg`, `gerber`, and `asme_elliptic`. The default is `goodman`.
+
+Example:
+
+```json
+{
+  "meanStress": 150000000,
+  "amplitudeStress": 100000000,
+  "material": "Structural steel S355",
+  "enduranceLimit": 245000000
+}
+```
+
+The tool warns when the endurance limit is estimated. It warns when the amplitude exceeds the endurance limit. It warns when the cycle reaches yield at its peak or trough.
+
 ## unit_convert
 
 Convert a value between two units.

examples/demo.ts

@@ -74,6 +74,7 @@ type ToolHandlers = {
   shaft_analysis: Handler;
   bearing_life: Handler;
   von_mises: Handler;
+  fatigue_analysis: Handler;
   unit_convert: Handler;
   material_lookup: Handler;
 };
@@ -88,6 +89,7 @@ const tools: NamedHandler[] = [
   ["shaft_analysis", toolHandlers.shaft_analysis],
   ["bearing_life", toolHandlers.bearing_life],
   ["von_mises", toolHandlers.von_mises],
+  ["fatigue_analysis", toolHandlers.fatigue_analysis],
   ["unit_convert", toolHandlers.unit_convert],
   ["unit_convert (torque to energy)", toolHandlers.unit_convert],
   ["material_lookup", toolHandlers.material_lookup],
@@ -145,6 +147,12 @@ const inputs: Array<Record<string, unknown>> = [
     yieldStrength: 355e6,
     outputUnits: { vonMisesStress: "MPa", maxShearStress: "MPa" },
   },
+  {
+    meanStress: 150e6,
+    amplitudeStress: 100e6,
+    material: "Structural steel S355",
+    outputUnits: { meanStress: "MPa", amplitudeStress: "MPa", minStress: "MPa", maxStress: "MPa", enduranceLimit: "MPa" },
+  },
   {
     value: 1000,
     from: "psi",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@engineerkit/engineer-mcp",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "MCP server for verified mechanical-engineering calculations, references, and material data.",
   "type": "module",
   "license": "MIT",