# 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:

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

Response:

```json
{
  "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](/docs#connect)), then call `execute` with:

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

### HTTP (no key)

```sh
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](/v1/tools/sequence-edit-script/versions/1.0.0).

### CLI

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

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

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