Evaluate math expressions, simplify algebra, and convert units via @mukundakatta/mathexpr-mcp (stdio)

@mukundakatta/mathexpr-mcp v0.1.0 — verified stdio recipe

Setup

npm install --prefix /tmp/mathexpr-mcp @mukundakatta/mathexpr-mcp
# Entry: node_modules/@mukundakatta/mathexpr-mcp/dist/server.js
# No API key needed — all computation is local

MCP client connection (Node SDK)

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";

const transport = new StdioClientTransport({
  command: "node",
  args: ["/tmp/mathexpr-mcp/node_modules/@mukundakatta/mathexpr-mcp/dist/server.js"],
  cwd: "/tmp/mathexpr-mcp"
});
const client = new Client({ name: "pathfinder", version: "1.0.0" });
await client.connect(transport);

2 tools

Verified traces (18 calls, 18 OK, 0 failures)

Arithmetic (5 calls):

1. eval({expression: "2 + 3 * 4"}) → 34ms — {"result": 14} (respects operator precedence)
2. eval({expression: "sqrt(144)"}) → 9ms — {"result": 12}
3. eval({expression: "sin(pi / 2)"}) → 6ms — {"result": 1} (built-in constants pi, e)
4. eval({expression: "log(e)"}) → 4ms — {"result": 1} (natural log)
5. eval({expression: "2^10"}) → 6ms — {"result": 1024}

Unit conversion (4 calls):

1. eval({expression: "3 inch to cm"}) → 10ms — {"result": "7.62 cm"}
2. eval({expression: "100 km to mile"}) → 8ms — {"result": "62.137119223733 mile"}
3. eval({expression: "212 degF to degC"}) → 10ms — {"result": "100 degC"} (Fahrenheit to Celsius)
4. eval({expression: "1 kg to lb"}) → 65ms — {"result": "2.2046226218488 lb"}

Variables via scope (1 call):

1. eval({expression: "x^2 + 2*x + 1", scope: {x: 3}}) → 56ms — {"result": 16} (substitutes x=3)

Advanced math (2 calls):

1. eval({expression: "factorial(10)"}) → 43ms — {"result": 3628800}
2. eval({expression: "det([[1,2],[3,4]])"}) → 49ms — {"result": -2} (matrix determinant!)

Simplify (4 calls):

1. simplify({expression: "x^2 + 2*x + 1"}) → 99ms — {"result": "x ^ 2 + 2 * x + 1"} (does NOT factor)
2. simplify({expression: "(a + b)^2"}) → 32ms — {"result": "(a + b) ^ 2"} (does NOT expand)
3. simplify({expression: "sin(x)^2 + cos(x)^2"}) → 45ms — {"result": "sin(x) ^ 2 + cos(x) ^ 2"} (does NOT apply trig identities)
4. simplify({expression: "2*x + 3*x - x"}) → 60ms — {"result": "4 * x"} ✓ (combines like terms)

Edge cases (2 calls):

1. eval({expression: "0/0"}) → 4ms — {"result": null} (NaN → null, not an error)
2. eval({expression: "1/0"}) → 6ms — {"result": null} (Infinity → null, not an error)

Key gotchas

1. `simplify` only combines like terms — it does NOT factor polynomials (x²+2x+1 stays as-is, not (x+1)²), does NOT expand (a+b)², and does NOT apply trig identities (sin²+cos² ≠ 1). For algebraic factoring, use eval with specific values instead.
2. Unit conversion uses `N unit to unit` syntax — natural language style inside the expression string. Temperature uses degF/degC/degK (not °F or fahrenheit).
3. Division by zero returns `null`, not an error — both 0/0 and 1/0 return {"result": null} with isError=false. Check for null results.
4. `scope` param for variable substitution — pass {x: 3, y: 4} to eval with variables. Useful for parameterized calculations.
5. Matrix operations supported — det([[1,2],[3,4]]) works. Pass matrices as nested arrays in the expression string.
6. All computation is local — no network calls, sub-100ms for all operations. Built on math.js library.
7. Output format differs by type — pure numeric results return {"result": number}, unit conversions return {"result": "value unit"} as string.