Jaro similarity compute

jaro-similarity-compute · version 1.0.0 · Text · free, no key needed

Compute Jaro similarity with a deterministic match window and exact reduced rational audit fields.

Use when you need to: compute Jaro similarity · exact Jaro string score · compare names with Jaro.

Decide before calling

Read the versioned contract and the supported scope below. Reuse jaro-similarity-compute@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 jaro-similarity-compute@1.0.0 for compute Jaro similarity. 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 Jaro similarity
• exact Jaro string score
• compare names with Jaro
• Jaro distance-style match score
• audit Jaro numerator and denominator
• deterministic character matching

Not supported

• Jaro-Winkler prefix adjustment
• locale-aware collation
• automatic Unicode normalization

Behavior

• Unicode code points are compared exactly without normalization, trimming, case folding, or locale behavior.
• The window is max(floor(max length / 2) - 1, 0); each left code point takes the lowest-index unmatched equal right code point in range.
• Jaro is (m/a + m/b + (m-t)/m)/3, with t equal to half the ordered mismatches rounded down.
• Both empty strings score 1; exactly one empty string or no matches scores 0.
• The reduced fraction is authoritative; score is its deterministic 12-place half-up decimal rendering.

Input

• left (string, required): max length 256
• right (string, required): max length 256

Output

• score (string, required): pattern ^(0|1|0\.[0-9]{12})$
• numerator (string, required): pattern ^[0-9]+$
• denominator (string, required): pattern ^[1-9][0-9]*$
• matches (integer, required): min 0; max 256
• transpositions (integer, required): min 0; max 128
• match_window (integer, required): min 0; max 127

Limits

• max string bytes: 1024
• max string code points: 256
• max output bytes: 65536

Example

Request input:

{
  "left": "MARTHA",
  "right": "MARHTA"
}

Response:

{
  "result": {
    "score": "0.944444444444",
    "numerator": "17",
    "denominator": "18",
    "matches": 6,
    "transpositions": 1,
    "match_window": 2
  }
}

How to call it

MCP

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

{
  "id": "jaro-similarity-compute",
  "version": "1.0.0",
  "input": {
    "left": "MARTHA",
    "right": "MARHTA"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/jaro-similarity-compute/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"left":"MARTHA","right":"MARHTA"}'

The machine-readable contract is at /v1/tools/jaro-similarity-compute/versions/1.0.0.

CLI

node cli.mjs run jaro-similarity-compute 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Jaro winkler compute: Compute Jaro-Winkler similarity with explicit threshold, prefix cap, and exact rational audit fields.
• Chrf components: Break down chrF/chrF++ into per-order n-gram counts, precision, recall and F, with configurable orders and averaging.
• Chrf compute: Compute exact chrF (character 6-gram F-beta, Popovic 2015) for hypothesis/reference segments, corpus and per segment.
• Jaro matches explain: Explain the deterministic Jaro match window, paired code points, and transposition flags.
• Chrf plus plus compute: Compute exact chrF++ (character 6-grams plus word 1-2-grams, Popovic 2017) with the word tokens it scored.
• Text shingle similarity: Exact shingle-set resemblance (Jaccard) and containment of two texts, with counts and shared shingles.