Vote condorcet winner

vote-condorcet-winner · version 1.0.0 · Optimization & voting · free, no key needed

Compute weighted pairwise counts, a strict Condorcet winner, and the generalized Smith set.

Use when you need to: compute Condorcet winner · calculate pairwise preference matrix · find Smith set.

Decide before calling

Read the versioned contract and the supported scope below. Reuse vote-condorcet-winner@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use vote-condorcet-winner@1.0.0 for compute Condorcet winner. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• compute Condorcet winner
• calculate pairwise preference matrix
• find Smith set
• count weighted ranked ballots
• analyze tied rankings
• analyze truncated ballots

Not supported

• choose a winner by instant-runoff voting
• resolve strategic voting or clone independence

Behavior

• Candidate and all output ordering exactly preserve the caller-supplied candidate order; ballot weights are positive integers.
• ranked-over-missing treats every ranked candidate as preferred to every omitted candidate; abstain excludes such pairs.
• A strict Condorcet winner has a strictly larger pairwise count than every opponent; ties do not win.
• smith_set is the generalized weak-majority top cycle: each returned candidate can reach every candidate along edges whose pairwise count is at least the reverse count.

Input

• candidates (array of string, required): min items 2; max items 50; each min length 1; each max length 64
• ballots (array of object, required): max items 1000
• missing_candidate_policy (one of "ranked-over-missing", "abstain", required)

Output

• candidates (array of string, required): min items 2; max items 50
• pairwise (array of object, required): min items 2; max items 50
• compared_weight (array of object, required): min items 2; max items 50
• condorcet_winner (string or null, required)
• smith_set (array of string, required): min items 1; max items 50
• audit (object, required)

Limits

• max candidates: 50
• max ballots: 1000
• max weight per ballot: 1000000
• max total weight: 1000000000
• max candidate bytes: 64

Example

Request input:

{
  "candidates": [
    "A",
    "B"
  ],
  "ballots": [
    {
      "ranking": [
        [
          "A"
        ],
        [
          "B"
        ]
      ],
      "weight": 3
    },
    {
      "ranking": [
        [
          "B"
        ],
        [
          "A"
        ]
      ],
      "weight": 1
    }
  ],
  "missing_candidate_policy": "ranked-over-missing"
}

Response:

{
  "result": {
    "candidates": [
      "A",
      "B"
    ],
    "pairwise": [
      {
        "candidate": "A",
        "counts": [
          0,
          3
        ]
      },
      {
        "candidate": "B",
        "counts": [
          1,
          0
        ]
      }
    ],
    "compared_weight": [
      {
        "candidate": "A",
        "counts": [
          0,
          4
        ]
      },
      {
        "candidate": "B",
        "counts": [
          4,
          0
        ]
      }
    ],
    "condorcet_winner": "A",
    "smith_set": [
      "A"
    ],
    "audit": {
      "ballot_count": 2,
      "total_weight": 4,
      "complete_weight": 4,
      "truncated_weight": 0,
      "tied_weight": 0
    }
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "vote-condorcet-winner",
  "version": "1.0.0",
  "input": {
    "candidates": [
      "A",
      "B"
    ],
    "ballots": [
      {
        "ranking": [
          [
            "A"
          ],
          [
            "B"
          ]
        ],
        "weight": 3
      },
      {
        "ranking": [
          [
            "B"
          ],
          [
            "A"
          ]
        ],
        "weight": 1
      }
    ],
    "missing_candidate_policy": "ranked-over-missing"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/vote-condorcet-winner/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"candidates":["A","B"],"ballots":[{"ranking":[["A"],["B"]],"weight":3},{"ranking":[["B"],["A"]],"weight":1}],"missing_candidate_policy":"ranked-over-missing"}'

The machine-readable contract is at /v1/tools/vote-condorcet-winner/versions/1.0.0.

CLI

node cli.mjs run vote-condorcet-winner 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

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