Sequence edit script

sequence-edit-script · version 1.0.0 · Sequences & diffs · free, no key needed

Compute the Myers shortest edit script between two bounded sequences, with keep/delete/insert counts.

Use when you need to: sequence edit script · myers shortest edit script of two sequences · sequence shortest edit script.

Supported

• sequence edit script
• myers shortest edit script of two sequences
• sequence shortest edit script

Not supported

• patience diff
• histogram diff
• fuzzy matching
• unicode normalization
• locale compare
• RFC 6902 JSON Patch

Behavior

• left and right are sequences of JSON null, boolean, string, or IEEE-754 safe integer items.
• Item equality is JavaScript === after validation; there is no case folding, locale compare, or Unicode normalization.
• ops is the Myers shortest edit script: one op per item, with keep, delete, and insert.
• When two Myers D-paths tie, the library prefers a delete from the left sequence.
• For left ["A","B"] and right ["B","A"] the script is delete A, keep B, insert A.
• keeps, deletions, and insertions count those op kinds. Empty vs empty yields ops [] and zero counts.
• The string "__proto__" is an ordinary item. Unknown input fields are rejected.

Input

• left (array of null or boolean or string or integer, required): max items 1024
• right (array of null or boolean or string or integer, required): max items 1024

Output

• ops (array of object, required): max items 4096
• keeps (integer, required): min 0
• deletions (integer, required): min 0
• insertions (integer, required): min 0

Limits

• max sequence items: 1024
• max item string bytes: 4096
• max text bytes: 262144
• max edit ops: 4096
• max output bytes: 1048576

Example

Request input:

{
  "left": [
    "A",
    "B"
  ],
  "right": [
    "B",
    "A"
  ]
}

Response:

{
  "result": {
    "ops": [
      {
        "op": "delete",
        "value": "A",
        "left_index": 0
      },
      {
        "op": "keep",
        "value": "B",
        "left_index": 1,
        "right_index": 0
      },
      {
        "op": "insert",
        "value": "A",
        "right_index": 1
      }
    ],
    "keeps": 1,
    "deletions": 1,
    "insertions": 1
  }
}

How to call it

MCP

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

{
  "id": "sequence-edit-script",
  "version": "1.0.0",
  "input": {
    "left": [
      "A",
      "B"
    ],
    "right": [
      "B",
      "A"
    ]
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/sequence-edit-script/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"left":["A","B"],"right":["B","A"]}'

The machine-readable contract is at /v1/tools/sequence-edit-script/versions/1.0.0.

CLI

node cli.mjs run sequence-edit-script 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Sequence LCS: Compute the longest common subsequence of two bounded sequences from the Myers shortest edit script.
• Sequence longest common substring: Find the longest contiguous common subarray of two bounded sequences.
• Sequence apply edit script: Apply a keep/delete/insert edit script to a bounded sequence with exact value matching and no fuzz.
• Sequence compose edit scripts: Compose two sequence edit scripts into one per-item keep/delete/insert script.
• Sequence three way merge: Three-way merge two sequence descendants against a shared base into clean or conflict regions.
• Sequence apply hunks: Apply disjoint original-address sequence hunks with exact context and no fuzz.