{
  "mcpServers": {
    "calculator": {
      "command": "npx",
      "args": ["-y", "calculator-mcp"]
    }
  }
}

claude mcp add calculator -- npx -y calculator-mcp

2 + 3 = 5

  0 ─▶ ● ─▶ ● ─▶ ○ ─▶ ○ ─▶ ○
       1    2    3    4    5
  ● = 2   ○ = 3   counted 5 ✓

— Methodology report —
- Represented 2 and 3 as Peano numerals.
- Constructed 5 successor nodes on top of zero.
- Counted the nodes by hand. Result verified by counting.
- Wall-clock time: 0 ms

A $1 pocket calculator would have done this in under a millisecond.

9 − 4 = 5

— Methodology report —
- Fielded Team A (9 members) against Team B (4 members).
- Round 1: Team B gains 1 metre, a hush falls over the stadium. Rope at -1 m.
- Round 2: Team A gains 1 metre, the coach is visibly emotional. Rope at 0 m.
- Round 3: Team A gains 1 metre, a hush falls over the stadium. Rope at 1 m.
- … 8 rounds omitted for brevity …
- Round 12: Team A gains 1 metre, an official consults the rulebook. Rope at 6 m.
- Round 13: Team B gains 1 metre, the crowd is on its feet. Rope at 5 m.
- Team A wins by 5 metres.
- Answer read off the rope's final position relative to the centre line.
- Wall-clock time: 0 ms

6 × 7 = 42

— Methodology report —
- Placed a 6×7 rectangle inside a 7×7 bounding box (area 49).
- Threw 100,000 darts. Hit rate: 85.5330%.
- Estimated area: 41.911, 95% confidence interval [41.804, 42.018].
- Rounded to 42.
- Audit: passed (independent auditor: the * operator).
- Wall-clock time: 13 ms

84 ÷ 7 = 12

— Methodology report —
- Outsourced the division to the language model that requested it.
- Computed by: claude-opus-5-5.
- This server performed 0 arithmetic operations.
- Wall-clock time: 0 ms

max(3, 5) = 5

— Methodology report —
- Started a 3-second timer and a 5-second timer simultaneously.
- The 3-second timer finished first. The 5-second timer finished last and is declared the maximum.
- Waited 5 seconds in total.
- Wall-clock time: 5013 ms

√10 = 3 remainder 1

— Methodology report —
- Guessed random integers between 0 and 10 until one squared correctly.
- Number of guesses: 1. Winning guess: 3 (3 × 3 = 9).
- 10 is not a perfect square. The irrational part is out of scope for this release.
- Wall-clock time: 0 ms

npm install
npm test
npm run build