CSV rename columns

csv-rename-columns · version 1.0.0 · CSV & tables · free, no key needed

Rename CSV headers by an exact from/to mapping, preserving row cells and column order.

Use when you need to: csv rename columns · rename csv columns · rename csv headers.

Supported

• csv rename columns
• rename csv columns
• rename csv headers

Not supported

• fuzzy header matching
• case-insensitive rename
• infer new names
• drop columns
• reorder columns
• read files
• fetch urls

Behavior

• mapping is a list of 1 to 256 { from, to } pairs; from and to are non-empty strings of at most 256 bytes.
• from values must be unique and each must equal a current header exactly; to values must be unique.
• A from equal to to is a no-op for that column. Column order and cell strings are unchanged.
• After rename, headers must remain unique; a to value must not collide with an unrenamed header.
• An empty document without a header is rejected; a header-only document is renamed and keeps zero data rows.
• The first output header name may not begin with U+FEFF because it is ambiguous with a CSV byte-order mark.

Input

• csv (string, required): max length 256000
• mapping (array of object, required): min items 1; max items 256

Output

• csv (string, required)

Limits

• max input bytes: 256000
• max data rows: 5000
• max columns: 256
• max header name bytes: 256
• max mapping entries: 256
• max output bytes: 256000

Example

Request input:

{
  "csv": "id,name,note\n1,Ada,\"hello, world\"\n",
  "mapping": [
    {
      "from": "name",
      "to": "full_name"
    },
    {
      "from": "id",
      "to": "user_id"
    }
  ]
}

Response:

{
  "result": {
    "csv": "user_id,full_name,note\n1,Ada,\"hello, world\"\n"
  }
}

How to call it

MCP

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

{
  "id": "csv-rename-columns",
  "version": "1.0.0",
  "input": {
    "csv": "id,name,note\n1,Ada,\"hello, world\"\n",
    "mapping": [
      {
        "from": "name",
        "to": "full_name"
      },
      {
        "from": "id",
        "to": "user_id"
      }
    ]
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/csv-rename-columns/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"csv":"id,name,note\n1,Ada,\"hello, world\"\n","mapping":[{"from":"name","to":"full_name"},{"from":"id","to":"user_id"}]}'

The machine-readable contract is at /v1/tools/csv-rename-columns/versions/1.0.0.

CLI

node cli.mjs run csv-rename-columns 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• CSV concat: Concatenate CSV documents that share identical headers, preserving document and row order.
• CSV dedupe: Remove duplicate CSV data rows while preserving the first occurrence.
• CSV drop columns: Drop named CSV columns and keep the remaining columns in original header order.
• CSV fill defaults: Replace empty cells in named CSV columns with exact default strings.
• CSV group count: Count CSV rows by exact named-column tuples in first-seen order.
• CSV merge columns: Join named CSV columns with an exact separator into one column.